Resources are the additional files and static content that your code uses, such as bitmaps, layout definitions, user interface strings, animation instructions, and more.

Always externalize app resources such as images and strings from your code, so that you can maintain them independently. Also, provide alternative resources for specific device configurations by grouping them in specially named resource directories. At runtime, Android uses the appropriate resource based on the current configuration. For example, you might want to provide a different UI layout depending on the screen size or different strings depending on the language setting.

Once you externalize your app resources, you can access them using resource IDs that are generated in your project's`R`class. This document shows you how to group the resources in your Android project. It also shows you how to provide alternative resources for specific device configurations and then access them from your app code or other XML files.

## Group resource types

Place each type of resource in a specific subdirectory of your project's`res/`directory. For example, here's the file hierarchy for a simple project:  

```
MyProject/
    src/
        MyActivity.java
    res/
        drawable/
            graphic.png
        layout/
            main.xml
            info.xml
        mipmap/
            icon.png
        values/
            strings.xml
```

The`res/`directory contains all the resources in its subdirectories: an image resource, two layout resources, a`mipmap/`directory for launcher icons, and a string resource file. The resource directory names are important and are described in table 1.

**Note:** For more information about using the mipmap folders, see[Put app icons in mipmap directories](https://developer.android.com/training/multiscreen/screendensities#mipmap).

**Table 1.** Resource directories supported inside project`res/`directory.

|  Directory  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          Resource Type                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|-------------| |
| `animator/` | XML files that define[Property animations](https://developer.android.com/guide/topics/graphics/prop-animation).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| `anim/`     | XML files that define[Tween animations](https://developer.android.com/guide/topics/graphics/view-animation#tween-animation). Property animations can also be saved in this directory, but the`animator/`directory is preferred for property animations to distinguish between the two types.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| `color/`    | XML files that define a state list of colors. For more information, see[Color state list resource](https://developer.android.com/guide/topics/resources/color-list-resource).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| `drawable/` | Bitmap files (PNG,`.9.png`, JPG, or GIF) or XML files that are compiled into the following drawable resource subtypes: - Bitmap files - Nine-patches (re-sizable bitmaps) - State lists - Shapes - Animation drawables - Other drawables For more information, see[Drawable resources](https://developer.android.com/guide/topics/resources/drawable-resource).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| `mipmap/`   | Drawable files for different launcher icon densities. For more information on managing launcher icons with`mipmap/`folders, see[Put app icons in mipmap directories](https://developer.android.com/training/multiscreen/screendensities#mipmap).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| `layout/`   | XML files that define a user interface layout. For more information, see[Layout resource](https://developer.android.com/guide/topics/resources/layout-resource).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| `menu/`     | XML files that define app menus, such as an options menu, context menu, or submenu. For more information, see[Menu resource](https://developer.android.com/guide/topics/resources/menu-resource).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| `raw/`      | Arbitrary files to save in their raw form. To open these resources with a raw[InputStream](https://developer.android.com/reference/java/io/InputStream), call[Resources.openRawResource()](https://developer.android.com/reference/android/content/res/Resources#openRawResource(int))with the resource ID, which is`R.raw.`*filename*. However, if you need access to the original filenames and file hierarchy, consider saving resources in the`assets/`directory instead of`res/raw/`. Files in`assets/`aren't given a resource ID, so you can only read them using[AssetManager](https://developer.android.com/reference/android/content/res/AssetManager).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| `values/`   | XML files that contain simple values, such as strings, integers, and colors. Whereas XML resource files in other`res/`subdirectories define a single resource based on the XML filename, files in the`values/`directory describe multiple resources. For a file in this directory, each child of the`<resources>`element defines a single resource. For example, a`<string>`element creates an`R.string`resource, and a`<color>`element creates an`R.color`resource. Because each resource is defined with its own XML element, you can name the file whatever you want and place different resource types in one file. However, for clarity, you might want to place unique resource types in different files. For example, here are some filename conventions for resources you can create in this directory: - `arrays.xml`for resource arrays ([Typed arrays](https://developer.android.com/guide/topics/resources/more-resources#TypedArray)) - `colors.xml`for[Color values](https://developer.android.com/guide/topics/resources/more-resources#Color) - `dimens.xml`for[Dimension values](https://developer.android.com/guide/topics/resources/more-resources#Dimension) - `strings.xml`for[String values](https://developer.android.com/guide/topics/resources/string-resource) - `styles.xml`for[Styles](https://developer.android.com/guide/topics/resources/style-resource) For more information, see[String resources](https://developer.android.com/guide/topics/resources/string-resource),[Style resource](https://developer.android.com/guide/topics/resources/style-resource), and[More resource types](https://developer.android.com/guide/topics/resources/more-resources). |
| `xml/`      | Arbitrary XML files that can be read at runtime by calling[Resources.getXML()](https://developer.android.com/reference/android/content/res/Resources#getXml(int)). Various XML configuration files must be saved here, such as a[Search configuration](https://developer.android.com/guide/topics/search/searchable-config).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| `font/`     | Font files with extensions such as TTF, OTF, or TTC, or XML files that include a`<font-family>`element. For more information about fonts as resources, see[Add a font as an XML resource](https://developer.android.com/guide/topics/ui/look-and-feel/fonts-in-xml).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |

**Caution:** Never save resource files directly inside the`res/`directory. It causes a compiler error.

For more information about the individual types of resources, see the[Resource types overview](https://developer.android.com/guide/topics/resources/available-resources).

The resources that you save in the subdirectories defined in table 1 are your default resources. That is, these resources define the default design and content for your app. However, different types of Android-powered devices might call for different types of resources.

For example, you can provide different layout resources for devices that have larger than normal screens to take advantage of the extra screen space. You can also provide different string resources that translate the text in your user interface based on the device's language setting. To provide these different resources for different device configurations, you need to provide alternative resources in addition to your default resources.

## Provide alternative resources

Most apps provide alternative resources to support specific device configurations. For instance, include alternative drawable resources for different screen densities and alternative string resources for different languages. At runtime, Android detects the current device configuration and loads the appropriate resources for your app.
![](https://developer.android.com/static/images/resources/resource_devices_diagram2.png)

**Figure 1.**Two devices using different layout resources based on screen size.

To specify configuration-specific alternatives for a set of resources, do the following:

1. Create a new directory in`res/`named in the form*<resources_name>* `-`*<qualifier>*.
   - *`<resources_name>`*is the directory name of the corresponding default resources (defined in table 1).
   - *`<qualifier>`*is a name that specifies an individual configuration for which these resources are to be used (defined in table 2).

   You can append more than one*`<qualifier>`*. Separate each one with a dash.

   **Caution:**When appending multiple qualifiers, you must place them in the same order in which they are listed in table 2. If the qualifiers are ordered incorrectly, the resources are ignored.
2. Save the appropriate alternative resources in this new directory. The resource files must be named exactly the same as the default resource files.

For example, here are some default and alternative resources:  

```
res/
    drawable/
        icon.png
        background.png
    drawable-hdpi/
        icon.png
        background.png
```

The`hdpi`qualifier indicates that the resources in that directory are for devices with a high-density screen. The images in these drawable directories are sized for specific screen densities, but the filenames are exactly the same. This way, the resource ID that you use to reference the`icon.png`or`background.png`image is always the same. Android selects the version of each resource that best matches the current device by comparing the device configuration information with the qualifiers in the resource directory name.

**Caution:** When defining an alternative resource, make sure you also define the resource in a default configuration. Otherwise, your app might encounter runtime exceptions when the device changes a configuration. For example, if you add a string to only`values-en`and not`values`, your app might encounter a`Resource Not Found`exception when the user changes the default system language.

Table 2 lists the valid configuration qualifiers in order of precedence. You can add multiple qualifiers to one directory name by separating each qualifier with a dash. If you use multiple qualifiers for a resource directory, you must add them to the directory name in the order they are listed in the table.

**Table 2.**Configuration qualifier names.

|                   Configuration                    |                                           Qualifier values                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------|-------------------------------------------------------------------------------------------------------| |
| MCC and MNC                                        | Examples: `mcc310` mcc310-mnc004 `mcc208-mnc00`                                                       | The mobile country code (MCC), optionally followed by the mobile network code (MNC) from the SIM card in the device. For example,`mcc310`is U.S. on any carrier,`mcc310-mnc004`is U.S. on Verizon, and`mcc208-mnc00`is France on Orange. If the device uses a radio connection (that is, it's a GSM phone), the MCC and MNC values come from the SIM card. You can also use the MCC alone, for example, to include country-specific legal resources in your app. If you need to specify based on the language only, then use the*language, script (optional), and region (optional)*qualifier instead. If you use the MCC and MNC qualifier, do so with care and test that it works as expected. Also see the configuration fields[mcc](https://developer.android.com/reference/android/content/res/Configuration#mcc), and[mnc](https://developer.android.com/reference/android/content/res/Configuration#mnc), which indicate the current mobile country code and mobile network code, respectively.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| Language, script (optional), and region (optional) | Examples: `en` `fr` `en-rUS` `fr-rFR` `fr-rCA` `b+en` `b+en+US` `b+es+419` `b+zh+Hant` `b+sr+Latn+RS` | The language is defined by a two-letter[ISO 639-1](http://www.loc.gov/standards/iso639-2/php/code_list.php)language code, optionally followed by a two-letter[ISO 3166-1-alpha-2](https://www.iso.org/obp/ui/#iso:pub:PUB500001:en)region code (preceded by lowercase`r`). The codes are*not* case-sensitive. The`r`prefix is used to distinguish the region portion. You can't specify a region alone. Android 7.0 (API level 24) introduced support for[BCP 47 language tags](https://tools.ietf.org/html/bcp47), which you can use to qualify language- and region-specific resources. A language tag is composed from a sequence of one or more subtags, each of which refines or narrows the range of language identified by the overall tag. For more information about language tags, see[Tags for Identifying Languages](https://tools.ietf.org/html/rfc5646). To use a BCP 47 language tag, concatenate`b+`and a two-letter[ISO 639-1](http://www.loc.gov/standards/iso639-2/php/code_list.php)language code, optionally followed by additional subtags separated by`+`. <br /> The language tag can change during the life of your app if users change their language in the system settings. For information about how this can affect your app during runtime, see[Handle configuration changes](https://developer.android.com/guide/topics/resources/runtime-changes). For a complete guide to localizing your app for other languages, See[Localize your app](https://developer.android.com/guide/topics/resources/localization). Also see the[getLocales()](https://developer.android.com/reference/android/content/res/Configuration#getLocales())method, which provides the defined list of locales. This list includes the primary locale.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Layout direction                                   | `ldrtl` `ldltr`                                                                                       | The layout direction of your app.`ldrtl`means "layout-direction-right-to-left."`ldltr`means "layout-direction-left-to-right" and is the default implicit value. This can apply to any resource, such as layouts, drawables, or values. For example, if you want to provide a specific layout for the Arabic language and a generic layout for any other "right-to-left" language, like Persian or Hebrew, then you use directories like the following: `res/` ` layout/` ` main.xml`(default layout) ` layout-ar/` ` main.xml`(specific layout for Arabic) ` layout-ldrtl/` ` main.xml`(any right-to-left language except for Arabic, because the "ar" language qualifier has a higher precedence) **Note:** To enable right-to-left layout features for your app, you must set[`SupportsRtl`](https://developer.android.com/guide/topics/manifest/application-element#supportsrtl)to`"true"`and set[`TargetSdkVersion`](https://developer.android.com/guide/topics/manifest/uses-sdk-element#target)to 17 or higher. *Added in API level 17.*                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| Smallest width                                     | `sw<N>dp` Examples: `sw320dp` `sw600dp` `sw720dp` etc.                                                | The shortest dimension of the screen area available to an app. Specifically, the app window's`smallestWidth`is the shortest of the window's available height and width. You can also think of it as the "smallest possible width" for the window. You can use this qualifier so that your app has at least`<N>`dps of width available for its UI. For example, if your layout requires that its smallest dimension of screen area be at least 600 dp at all times, then you can use this qualifier to create the layout resources in a`res/layout-sw600dp/`directory. The system uses these resources only when the smallest dimension of available screen is at least 600 dp, regardless of whether the 600 dp side is the user-perceived height or width. The smallest width can change if the window is resized, changing the available width/height, or repositioned, potentially changing the system insets. Using smallest width to determine the general screen size is useful because width is often the driving factor in designing a layout. A UI often scrolls vertically, but has fairly hard constraints on the minimum space it needs horizontally. The available width is also the key factor in determining whether to use a one-pane layout for handsets or a multipane layout for tablets. Thus, you likely care most about what the smallest possible width is on each device. The smallest width of a device takes into account screen decorations and system UI. For example, if the device has persistent UI elements on the screen that account for space along the axis of the smallest width, the system declares the smallest width to be smaller than the actual screen size, because those are screen pixels not available for your UI. Some values you might use here for common screen sizes: - 320, for devices with screen configurations such as: - 240x320 ldpi (QVGA handset) - 320x480 mdpi (handset) - 480x800 hdpi (high-density handset) - 480, for screens such as 480x800 mdpi (tablet/handset) - 600, for screens such as 600x1024 mdpi (7" tablet) - 720, for screens such as 720x1280 mdpi (10" tablet) When your app provides multiple resource directories with different values for the`smallestWidth`qualifier, the system uses the one closest to (without exceeding) the device's`smallestWidth`. *Added in API level 13.* Also see the[`android:requiresSmallestWidthDp`](https://developer.android.com/guide/topics/manifest/supports-screens-element#requiresSmallest)attribute, which declares the minimum`smallestWidth`with which your app is compatible, and the[smallestScreenWidthDp](https://developer.android.com/reference/android/content/res/Configuration#smallestScreenWidthDp)configuration field, which holds the device's`smallestWidth`value. For more information about designing for different screens using this qualifier, see[Responsive/adaptive design with views](https://developer.android.com/develop/ui/views/layout/responsive-adaptive-design-with-views).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| Available width and height                         | `w<N>dp` `h<N>dp` Examples: `w720dp` `w1024dp` `h720dp` `h1024dp` etc.                                | Specifies the minimum available screen width or height (in`dp`units defined by the`<N>`value) at which the resource is used. These configuration values are compared to the current display width and height as the device orientation changes between portrait and landscape, the device folds or unfolds, or the system enters or exits multi-window mode. In multi-window mode, the values reflect the width and height of the window that contains the app, not the width and height of the device screen. Similarly, for embedded activities, the values pertain to the width and height of the individual activities, not the width and height of the screen. For more information, see[Activity embedding](https://developer.android.com/guide/topics/large-screens/activity-embedding). Available width and height are often useful for determining whether to use a multipane layout, because even on a tablet device you often don't want the same multipane layout for portrait orientation as you do for landscape. Thus, you can use these to specify the minimum width and/or height required for the layout, instead of using both the screen size and orientation qualifiers together. When your app provides multiple resource directories with different values for these configurations, the system uses the one closest to (without exceeding) the device's current screen width.*Closest to*is determined by adding the differences between the actual screen width and the specified width to the difference between the actual screen height and the specified height, with unspecified heights and widths having a value of 0. The values exclude the area occupied by[Window insets](https://developer.android.com/reference/android/view/WindowInsets), so if the device has persistent UI elements on the edges of the display, the values for width and height are smaller than the real screen dimensions, even when the app is displayed edge to edge using[`Window.setDecorFitsSystemWindows`](https://developer.android.com/reference/android/view/Window#setDecorFitsSystemWindows(boolean))or[`WindowCompat.setDecorFitsSystemWindows`](https://developer.android.com/reference/androidx/core/view/WindowCompat#setDecorFitsSystemWindows(android.view.Window,boolean)). Some vertical screen decorations that aren't fixed (such as a phone status bar that can be hidden when full screen) are*not*accounted for here, nor are window decorations like the title bar or action bar, so apps must be prepared to deal with a somewhat smaller space than they specify. **Note:**The system chooses the resource that matches both in width and height. Therefore a resource that specifies both is strongly preferred over one that specifies only one or the other. For example, if the actual screen is 720 dp wide by 1280 dp high and one resource is qualified with w720dp and another is qualified as w700dp-h1200dp, the latter is chosen even though the former is an exact match for what it specifies. *Added in API level 13.* Also see the[screenWidthDp](https://developer.android.com/reference/android/content/res/Configuration#screenWidthDp)and[screenHeightDp](https://developer.android.com/reference/android/content/res/Configuration#screenHeightDp)configuration fields, which hold the current screen width and height. For more information about designing for different screens using this qualifier, see[Responsive/adaptive design with views](https://developer.android.com/develop/ui/views/layout/responsive-adaptive-design-with-views). |
| Screen size                                        | `small` `normal` `large` `xlarge`                                                                     | - `small`: screens that are of similar size to a low-density QVGA screen. The minimum layout size for a small screen is approximately 320x426 dp units. Examples are QVGA low density and VGA high density. - `normal`: screens that are of similar size to a medium-density HVGA screen. The minimum layout size for a normal screen is approximately 320x470 dp units. Examples of such screens are a WQVGA low density, HVGA medium density, and WVGA high density. - `large`: screens that are of similar size to a medium-density VGA screen. The minimum layout size for a large screen is approximately 480x640 dp units. Examples are VGA and WVGA medium-density screens. - `xlarge`: screens that are considerably larger than the traditional medium-density HVGA screen. The minimum layout size for an xlarge screen is approximately 720x960 dp units. In most cases, devices with extra-large screens are too large to carry in a pocket and most likely are tablet-style devices.*Added in API level 9.* **Note:** Using a size qualifier does not imply that the resources are*only* for screens of that size. If you do not provide alternative resources with qualifiers that better match the current device configuration, the system can use whichever resources are the[best match](https://developer.android.com/guide/topics/resources/providing-resources#BestMatch). **Caution:** If all your resources use a size qualifier that is*larger* than the current screen, the system**doesn't** use them and your app crashes at runtime. This happens, for example, if all layout resources are tagged with the`xlarge`qualifier but the device has a normal-size screen. *Added in API level 4.* Also see the[screenLayout](https://developer.android.com/reference/android/content/res/Configuration#screenLayout)configuration field, which indicates whether the screen is small, normal, or large. For more information, see[Screen compatibility overview](https://developer.android.com/guide/practices/screens_support).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Screen aspect                                      | `long` `notlong`                                                                                      | - `long`: long screens, such as WQVGA, WVGA, FWVGA - `notlong`: not long screens, such as QVGA, HVGA, and VGA *Added in API level 4.* This is based purely on the aspect ratio of the screen (a`long`screen is wider). This isn't related to the screen orientation. Also see the[screenLayout](https://developer.android.com/reference/android/content/res/Configuration#screenLayout)configuration field, which indicates whether the screen is long.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Round screen                                       | `round` `notround`                                                                                    | - `round`: round screens, such as a round wearable device - `notround`: rectangular screens, such as phones or tablets *Added in API level 23.* Also see the[isScreenRound()](https://developer.android.com/reference/android/content/res/Configuration#isScreenRound())configuration method, which indicates whether the screen is round.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Wide Color Gamut                                   | `widecg` `nowidecg`                                                                                   | - `widecg`: displays with a wide color gamut such as Display P3 or AdobeRGB - `nowidecg`: displays with a narrow color gamut such as sRGB *Added in API level 26.* Also see the[isScreenWideColorGamut()](https://developer.android.com/reference/android/content/res/Configuration#isScreenWideColorGamut())configuration method, which indicates whether the screen has a wide color gamut.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| High Dynamic Range (HDR)                           | `highdr` `lowdr`                                                                                      | - `highdr`: displays with a high dynamic range - `lowdr`: displays with a low/standard dynamic range *Added in API level 26.* Also see the[isScreenHdr()](https://developer.android.com/reference/android/content/res/Configuration#isScreenHdr())configuration method, which indicates whether the screen has HDR capabilities.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| Screen orientation                                 | `port` `land`                                                                                         | - `port`: device is in portrait orientation (vertical) - `land`: device is in landscape orientation (horizontal) This can change during the life of your app if the user rotates the screen. For information about how this affects your app during runtime, see[Handle configuration changes](https://developer.android.com/guide/topics/resources/runtime-changes). Also see the[orientation](https://developer.android.com/reference/android/content/res/Configuration#orientation)configuration field, which indicates the current device orientation.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| UI mode                                            | `car` `desk` `television` `appliance` `watch` `vrheadset`                                             | - `car`: device is displaying in a car dock - `desk`: device is displaying in a desk dock - `television`: device is displaying on a television, providing a "ten-foot" experience where its UI is on a large screen that the user is far away from, and the experience is primarily oriented around D-pad or other non-pointer interaction - `appliance`: device is serving as an appliance, with no display - `watch`: device has a display and is worn on the wrist - `vrheadset`: device is displaying in a virtual reality headset *Added in API level 8; television added in API 13; watch added in API 20.* For information about how your app can respond when the device is inserted into or removed from a dock, read[Determine and monitor the docking state and type](https://developer.android.com/training/monitoring-device-state/docking-monitoring). This can change during the life of your app if the user places the device in a dock. You can enable or disable some of these modes using[UiModeManager](https://developer.android.com/reference/android/app/UiModeManager). For information about how this affects your app during runtime, see[Handle configuration changes](https://developer.android.com/guide/topics/resources/runtime-changes).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| Night mode                                         | `night` `notnight`                                                                                    | - `night`: night time - `notnight`: day time *Added in API level 8.* This can change during the life of your app if night mode is left in auto mode (default), in which case the mode changes based on the time of day. You can enable or disable this mode using[UiModeManager](https://developer.android.com/reference/android/app/UiModeManager). For information about how this affects your app during runtime, see[Handle configuration changes](https://developer.android.com/guide/topics/resources/runtime-changes).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| Screen pixel density (dpi)                         | `ldpi` `mdpi` `hdpi` `xhdpi` `xxhdpi` `xxxhdpi` `nodpi` `tvdpi` `anydpi` *nnn*`dpi`                   | - `ldpi`: low-density screens; approximately 120 dpi. - `mdpi`: medium-density (on traditional HVGA) screens; approximately 160 dpi. - `hdpi`: high-density screens; approximately 240 dpi. - `xhdpi`: extra-high-density screens; approximately 320 dpi.*Added in API level 8.* - `xxhdpi`: extra-extra-high-density screens; approximately 480 dpi.*Added in API level 16.* - `xxxhdpi`: extra-extra-extra-high-density uses (launcher icon only---see[Support different pixel densities](https://developer.android.com/training/multiscreen/screendensities)); approximately 640 dpi.*Added in API level 18.* - `nodpi`: used for bitmap resources that you don't want to be scaled to match the device density. - `tvdpi`: screens somewhere between mdpi and hdpi; approximately 213 dpi. This isn't considered a "primary" density group. It is mostly intended for 720p televisions, and most apps don't need it. For 1080p TV panels, use`xhdpi`, and for 4K TV panels, use`xxxhdpi`.*Added in API level 13.* - `anydpi`: matches all screen densities and takes precedence over other qualifiers. This is useful for[vector drawables](https://developer.android.com/training/material/drawables#VectorDrawables).*Added in API level 21.* - *nnn*`dpi`: used to represent non-standard densities, where*nnn*is a positive integer screen density. This isn't used in most cases. Using standard density buckets greatly reduces the overhead of supporting the various device screen densities on the market. There is a 3:4:6:8:12:16 scaling ratio between the six primary densities (ignoring the tvdpi density). So, a 9x9 bitmap in ldpi is 12x12 in mdpi, 18x18 in hdpi, 24x24 in xhdpi, and so on. **Note:** Using a density qualifier doesn't imply that the resources are*only* for screens of that density. If you don't provide alternative resources with qualifiers that better match the current device configuration, the system uses whichever resources are the[best match](https://developer.android.com/guide/topics/resources/providing-resources#BestMatch). For more information about how to handle different screen densities and how Android might scale your bitmaps to fit the current density, see[Screen compatibility overview](https://developer.android.com/guide/practices/screens_support).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Touchscreen type                                   | `notouch` `finger`                                                                                    | - `notouch`: device doesn't have a touchscreen. - `finger`: device has a touchscreen that is intended to be used through direction interaction of the user's finger. Also see the[touchscreen](https://developer.android.com/reference/android/content/res/Configuration#touchscreen)configuration field, which indicates the type of touchscreen on the device.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| Keyboard availability                              | `keysexposed` `keyshidden` `keyssoft`                                                                 | - `keysexposed`: device has a keyboard available. If the device has a software keyboard enabled (which is likely), this is used even when the hardware keyboard*isn't*exposed to the user or when the device has no hardware keyboard. If no software keyboard is provided or it's disabled, then this is only used when a hardware keyboard is exposed. - `keyshidden`: device has a hardware keyboard available but it is hidden*and* the device does*not*have a software keyboard enabled. - `keyssoft`: device has a software keyboard enabled, whether it's visible or not. If you provide`keysexposed`resources, but not`keyssoft`resources, the system uses the`keysexposed`resources regardless of whether a keyboard is visible, as long as the system has a software keyboard enabled. This can change during the life of your app if the user opens a hardware keyboard. For information about how this affects your app during runtime, see[Handle configuration changes](https://developer.android.com/guide/topics/resources/runtime-changes). Also see the configuration fields[hardKeyboardHidden](https://developer.android.com/reference/android/content/res/Configuration#hardKeyboardHidden)and[keyboardHidden](https://developer.android.com/reference/android/content/res/Configuration#keyboardHidden), which indicate the visibility of a hardware keyboard and the visibility of any kind of keyboard (including software), respectively.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| Primary text input method                          | `nokeys` `qwerty` `12key`                                                                             | - `nokeys`: device has no hardware keys for text input. - `qwerty`: device has a hardware QWERTY keyboard, whether it's visible to the user or not. - `12key`: device has a hardware 12-key keyboard, whether it's visible to the user or not. Also see the[keyboard](https://developer.android.com/reference/android/content/res/Configuration#keyboard)configuration field, which indicates the primary text input method available.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| Navigation key availability                        | `navexposed` `navhidden`                                                                              | - `navexposed`: navigation keys are available to the user. - `navhidden`: navigation keys aren't available (such as behind a closed lid). This can change during the life of your app if the user reveals the navigation keys. For information about how this affects your app during runtime, see[Handle configuration changes](https://developer.android.com/guide/topics/resources/runtime-changes). Also see the[navigationHidden](https://developer.android.com/reference/android/content/res/Configuration#navigationHidden)configuration field, which indicates whether the navigation keys are hidden.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| Primary non-touch navigation method                | `nonav` `dpad` `trackball` `wheel`                                                                    | - `nonav`: device has no navigation facility other than using the touchscreen. - `dpad`: device has a directional-pad (D-pad) for navigation. - `trackball`: device has a trackball for navigation. - `wheel`: device has a directional wheel(s) for navigation (uncommon). Also see the[navigation](https://developer.android.com/reference/android/content/res/Configuration#navigation)configuration field, which indicates the type of navigation method available.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Platform version (API level)                       | Examples: `v3` `v4` `v7` etc.                                                                         | The API level supported by the device. For example,`v1`for API level 1 (devices with Android 1.0 or higher) and`v4`for API level 4 (devices with Android 1.6 or higher). For more information about these values, see the[Android API levels](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)document.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |

**Note:** Not all versions of Android support all the qualifiers. Using a new qualifier implicitly adds the platform version qualifier so that older devices can ignore it. For example, using a`w600dp`qualifier automatically includes the`v13`qualifier, because the available-width qualifier was new in API level 13. To avoid any issues, always include a set of default resources (a set of resources with*no qualifiers* ). For more information, see the section about[Providing the best device compatibility with resources](https://developer.android.com/guide/topics/resources/providing-resources#Compatibility).

### Qualifier name rules

Here are some rules about using configuration qualifier names:

- You can specify multiple qualifiers for a single set of resources, separated by dashes. For example,`drawable-en-rUS-land`applies to US-English devices in landscape orientation.
- The qualifiers must be in the order listed in[table 2](https://developer.android.com/guide/topics/resources/providing-resources#table2).
  - Wrong:`drawable-hdpi-port/`
  - Correct:`drawable-port-hdpi/`
- Alternative resource directories can't be nested. For example, you can't have`res/drawable/drawable-en/`.
- Values are case-insensitive. The resource compiler converts directory names to lowercase before processing to avoid problems on case-insensitive file systems. Any capitalization in the names is only to benefit readability.
- Only one value for each qualifier type is supported. For example, if you want to use the same drawable files for Spain and France, you*can't* have a directory named`drawable-es-fr/`. Instead, you need two resource directories, such as`drawable-es/`and`drawable-fr/`, which contain the appropriate files. However, you aren't required to actually duplicate the files in both locations. Instead, you can create an*alias* to a resource, as described in the[Create alias resources](https://developer.android.com/guide/topics/resources/providing-resources#AliasResources)section.

After you save alternative resources into directories named with these qualifiers, Android automatically applies the resources in your app based on the current device configuration. Each time a resource is requested, Android checks for alternative resource directories that contain the requested resource file, then[finds the best-matching resource](https://developer.android.com/guide/topics/resources/providing-resources#BestMatch).

If there are no alternative resources that match a particular device configuration, then Android uses the corresponding default resources---the set of resources for a particular resource type that doesn't include a configuration qualifier.

### Create alias resources

When you have a resource that you'd like to use for more than one device configuration but you don't want to provide it as a default resource, you don't need to put the same resource in more than one alternative resource directory. Instead, you can create an alternative resource that acts as an alias for a resource saved in your default resource directory.

**Note:** Not all resources offer a mechanism by which you can create an alias to another resource. In particular, animation, menu, raw, and other unspecified resources in the`xml/`directory don't offer this feature.

For example, imagine you have an app icon,`icon.png`, and need a unique version of it for different locales. However, two locales, English-Canadian and French-Canadian, need to use the same version. You don't need to copy the same image into the resource directory for both English-Canadian and French-Canadian. Instead, you can save the image that's used for both using any name*other than* `icon.png`, such as`icon_ca.png`, and put it in the default`res/drawable/`directory. Then create an`icon.xml`file in`res/drawable-en-rCA/`and`res/drawable-fr-rCA/`that refers to the`icon_ca.png`resource using the`<bitmap>`element. This lets you store just one version of the PNG file and two small XML files that point to it. See the examples in the following sections for details.

#### Drawable

To create an alias to an existing drawable, use the`<drawable>`element:  

```xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <drawable name="icon">@drawable/icon_ca</drawable>
</resources>
```

If you save this file as`icon.xml`in an alternative resource directory, such as`res/values-en-rCA/`, it is compiled into a resource that you can reference as`R.drawable.icon`, but is actually an alias for the`R.drawable.icon_ca`resource, which is saved in`res/drawable/`.

#### Layout

To create an alias to an existing layout, use the`<include>`element, wrapped in a`<merge>`:  

```xml
<?xml version="1.0" encoding="utf-8"?>
<merge>
    <include layout="@layout/main_ltr"/>
</merge>
```

If you save this file as`main.xml`, it is compiled into a resource you can reference as`R.layout.main`, but is actually an alias for the`R.layout.main_ltr`resource.

#### Strings and other simple values

To create an alias to an existing string, use the resource ID of the desired string as the value for the new string:  

```xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello</string>
    <string name="hi">@string/hello</string>
</resources>
```

The`R.string.hi`resource is now an alias for the`R.string.hello`.

[Other simple values](https://developer.android.com/guide/topics/resources/more-resources)work the same way, such as colors:  

```xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="red">#f00</color>
    <color name="highlight">@color/red</color>
</resources>
```

## Access your app resources

Once you provide a resource in your application, you can apply it by referencing its resource ID. All resource IDs are defined in your project's`R`class, which the`aapt`tool automatically generates.

When your application is compiled,`aapt`generates the`R`class, which contains resource IDs for all the resources in your`res/`directory. For each type of resource, there is an`R`subclass, such as`R.drawable`for all drawable resources. And for each resource of that type, there is a static integer, for example,`R.drawable.icon`. This integer is the resource ID that you can use to retrieve your resource.

Although the`R`class is where resource IDs are specified, you don't need to look there to discover a resource ID. A resource ID is always composed of the following:

- The*resource type* : each resource is grouped into a "type," such as`string`,`drawable`, and`layout`. For more information about the different types, see[Resource types overview](https://developer.android.com/guide/topics/resources/available-resources).
- The*resource name* , which is either the filename excluding the extension or the value in the XML`android:name`attribute, if the resource is a simple value, such as a string.

There are two ways you can access a resource:

- **In code:** using a static integer from a subclass of your`R`class, such as:  

  ```
  R.string.hello
  ```

  `string`is the resource type and`hello`is the resource name. There are many Android APIs that can access your resources when you provide a resource ID in this format. For more information, see the[Access resources in code](https://developer.android.com/guide/topics/resources/providing-resources#ResourcesFromCode)section.
- **In XML:** using a special XML syntax that corresponds to the resource ID defined in your`R`class, such as:  

  ```
  @string/hello
  ```

  `string`is the resource type and`hello`is the resource name. You can use this syntax in an XML resource any place where a value is expected that you provide in a resource. For more information, see the[Access resources from XML](https://developer.android.com/guide/topics/resources/providing-resources#ResourcesFromXml)section.

### Access resources in code

You can use a resource in code by passing the resource ID as a method parameter. For example, you can set an[ImageView](https://developer.android.com/reference/android/widget/ImageView)to use the`res/drawable/myimage.png`resource using[setImageResource()](https://developer.android.com/reference/android/widget/ImageView#setImageResource(int)):  

### Kotlin

```kotlin
val imageView = findViewById(R.id.myimageview) as ImageView
imageView.setImageResource(R.drawable.myimage)
```

### Java

```java
ImageView imageView = (ImageView) findViewById(R.id.myimageview);
imageView.setImageResource(R.drawable.myimage);
```

You can also retrieve individual resources using methods in[Resources](https://developer.android.com/reference/android/content/res/Resources), which you can get an instance of with[getResources()](https://developer.android.com/reference/android/content/Context#getResources()).

#### Syntax

Here's the syntax to reference a resource in code:  

```
[<package_name>.]R.<resource_type>.<resource_name>
```

- *`<package_name>`*is the name of the package in which the resource is located (not required when referencing resources from your own package).
- *`<resource_type>`* is the`R`subclass for the resource type.
- *`<resource_name>`* is either the resource filename without the extension or the`android:name`attribute value in the XML element, for simple values.

For more information about each resource type and how to reference them, see[Resource types overview](https://developer.android.com/guide/topics/resources/available-resources).

#### Use cases

There are many methods that accept a resource ID parameter, and you can retrieve resources using methods in[Resources](https://developer.android.com/reference/android/content/res/Resources). You can get an instance of`Resources`using[Context.getResources()](https://developer.android.com/reference/android/content/Context#getResources()).

Here are some examples of accessing resources in code:  

### Kotlin

```kotlin
// Load a background for the current screen from a drawable resource.
window.setBackgroundDrawableResource(R.drawable.my_background_image)

// Set the Activity title by getting a string from the Resources object, because
//  this method requires a CharSequence rather than a resource ID.
window.setTitle(resources.getText(R.string.main_title))

// Load a custom layout for the current screen.
setContentView(R.layout.main_screen)

// Set a slide in animation by getting an Animation from the Resources object.
flipper.setInAnimation(AnimationUtils.loadAnimation(this,
        R.anim.hyperspace_in))

// Set the text on a TextView object using a resource ID.
val msgTextView = findViewById(R.id.msg) as TextView
msgTextView.setText(R.string.hello_message)
```

### Java

```java
// Load a background for the current screen from a drawable resource.
getWindow().setBackgroundDrawableResource(R.drawable.my_background_image) ;

// Set the Activity title by getting a string from the Resources object, because
//  this method requires a CharSequence rather than a resource ID.
getWindow().setTitle(getResources().getText(R.string.main_title));

// Load a custom layout for the current screen.
setContentView(R.layout.main_screen);

// Set a slide in animation by getting an Animation from the Resources object.
flipper.setInAnimation(AnimationUtils.loadAnimation(this,
        R.anim.hyperspace_in));

// Set the text on a TextView object using a resource ID.
TextView msgTextView = (TextView) findViewById(R.id.msg);
msgTextView.setText(R.string.hello_message);
```

**Caution:** Don't modify the`R.java`file by hand. It is generated by the`aapt`tool when your project is compiled. Any changes are overridden next time you compile.

### Access resources from XML

You can define values for some XML attributes and elements using a reference to an existing resource. You often do this when creating layout files, to supply strings and images for your widgets.

For example, if you add a[Button](https://developer.android.com/reference/android/widget/Button)to your layout, use a[string resource](https://developer.android.com/guide/topics/resources/string-resource)for the button text:  

```xml
<Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/submit" />
```

#### Syntax

Here is the syntax to reference a resource in an XML resource:  

```xml
@[<package_name>:]<resource_type>/<resource_name>
```

- `<package_name>`is the name of the package in which the resource is located (not required when referencing resources from the same package).
- `<resource_type>`is the`R`subclass for the resource type.
- `<resource_name>`is either the resource filename without the extension or the`android:name`attribute value in the XML element, for simple values.

For more information about each resource type and how to reference them, see[Resource types overview](https://developer.android.com/guide/topics/resources/available-resources).

#### Use cases

In some cases, you must use a resource for a value in XML, such as to apply a drawable image to a widget, but you can also use a resource in XML any place that accepts a simple value. For example, if you have the following resource file that includes a[color resource](https://developer.android.com/guide/topics/resources/more-resources#Color)and a[string resource](https://developer.android.com/guide/topics/resources/string-resource):  

```xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
   <color name="opaque_red">#f00</color>
   <string name="hello">Hello!</string>
</resources>
```

You can use these resources in the following layout file to set the text color and text string:  

```xml
<?xml version="1.0" encoding="utf-8"?>
<EditText xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:textColor="@color/opaque_red"
    android:text="@string/hello" />
```

In this case, you don't need to specify the package name in the resource reference, because the resources are from your own package. To reference a system resource, you need to include the package name, as shown in the following example:  

```xml
<?xml version="1.0" encoding="utf-8"?>
<EditText xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:textColor="@android:color/secondary_text_dark"
    android:text="@string/hello" />
```

**Note:** Always use string resources, so that your application can be localized for other languages. For information about creating alternative resources (such as localized strings), see[Provide alternative resources](https://developer.android.com/guide/topics/resources/providing-resources#AlternativeResources). For a complete guide to localizing your application for other languages, see[Localize your app](https://developer.android.com/guide/topics/resources/localization).

You can even use resources in XML to create aliases. For example, you can create a drawable resource that is an alias for another drawable resource:  

```xml
<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
    android:src="@drawable/other_drawable" />
```

This sounds redundant, but can be very useful when using alternative resource. For more information, see the section about[creating alias resources](https://developer.android.com/guide/topics/resources/providing-resources#AliasResources).

#### Reference style attributes

A style attribute resource lets you reference the value of an attribute in the currently applied theme. Referencing a style attribute lets you customize the look of UI elements by styling them to match standard variations supplied by the current theme, instead of supplying a hardcoded value. Referencing a style attribute essentially says, "Use the style that is defined by this attribute in the current theme."

To reference a style attribute, the name syntax is almost identical to the normal resource format, but instead of the "at" symbol (`@`), use a question mark (`?`). The resource type portion is optional. So the reference syntax is as follows:  

```
?[<package_name>:][<resource_type>/]<resource_name>
```

For example, here's how you can reference an attribute to set the text color to match the secondary text color of the system theme:  

```xml
<EditText id="text"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:textColor="?android:textColorSecondary"
    android:text="@string/hello_world" />
```

Here, the`android:textColor`attribute specifies the name of a style attribute in the current theme. Android now uses the value applied to the`android:textColorSecondary`style attribute as the value for`android:textColor`in this widget. Because the system resource tool knows that an attribute resource is expected in this context, you do not need to explicitly state the type, which is`?android:attr/textColorSecondary`. You can exclude the`attr`type.

### Access original files

While uncommon, you might need access your original files and directories. If you do, then saving your files in`res/`won't work for you, because the only way to read a resource from`res/`is with the resource ID. Instead, you can save your resources in the`assets/`directory.

Files saved in the`assets/`directory are*not* given a resource ID, so you can't reference them through the`R`class or from XML resources. Instead, you can query files in the`assets/`directory like a normal file system and read raw data using[AssetManager](https://developer.android.com/reference/android/content/res/AssetManager).

However, if all you require is the ability to read raw data (such as a video or audio file), then save the file in the`res/raw/`directory and read a stream of bytes using[openRawResource()](https://developer.android.com/reference/android/content/res/Resources#openRawResource(int)).

### Access platform resources

Android contains a number of standard resources, such as styles, themes, and layouts. To access these resources, qualify your resource reference with the`android`package name. For example, Android provides a layout resource you can use for list items in a[ListAdapter](https://developer.android.com/reference/android/widget/ListAdapter):  

### Kotlin

```kotlin
listAdapter = ArrayAdapter(this, android.R.layout.simple_list_item_1, myarray)
```

### Java

```java
setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, myarray));
```

In this example,[simple_list_item_1](https://developer.android.com/reference/android/R.layout#simple_list_item_1)is a layout resource defined by the platform for items in a[ListView](https://developer.android.com/reference/android/widget/ListView). You can use this instead of creating your own layout for list items.

## Provide the best device compatibility with resources

For your app to support multiple device configurations, it's very important that you always provide default resources for each type of resource that your app uses.

For example, if your app supports several languages, always include a`values/`directory (in which your strings are saved)*without* a[language and region qualifier](https://developer.android.com/guide/topics/resources/providing-resources#LocaleQualifier). If you instead put all your string files in directories that have a language and region qualifier, then your app crashes when run on a device set to a language that your strings don't support.

As long as you provide default`values/`resources, then your app runs properly, even if the user doesn't understand the language it presents. It's better than crashing.

Likewise, if you provide different layout resources based on the screen orientation, pick one orientation as your default. For example, instead of providing layout resources in`layout-land/`for landscape and`layout-port/`for portrait, leave one as the default, such as`layout/`for landscape and`layout-port/`for portrait.

Providing default resources is important not only because your app might run on a configuration you hadn't anticipated, but also because new versions of Android sometimes add configuration qualifiers that older versions don't support. If you use a new resource qualifier, but maintain code compatibility with older versions of Android, then when an older version of Android runs your app, it crashes if you don't provide default resources, because it can't use the resources named with the new qualifier.

For example, if your[`minSdkVersion`](https://developer.android.com/guide/topics/manifest/uses-sdk-element#min)is set to 4, and you qualify all of your drawable resources using[night mode](https://developer.android.com/guide/topics/resources/providing-resources#NightQualifier)(`night`or`notnight`, which were added in API level 8), then an API level 4 device can't access your drawable resources and crashes. In this case, you probably want`notnight`to be your default resources, so exclude that qualifier and put your drawable resources in either`drawable/`or`drawable-night/`.

In short, to provide the best device compatibility, always provide default resources for the resources your app needs to perform properly. Then create alternative resources for specific device configurations using configuration qualifiers.

There is one exception to this rule: If your app's[`minSdkVersion`](https://developer.android.com/guide/topics/manifest/uses-sdk-element#min)is 4 or greater, you*don't* need default drawable resources when you provide alternative drawable resources with the[screen density](https://developer.android.com/guide/topics/resources/providing-resources#DensityQualifier)qualifier. Even without default drawable resources, Android can find the best match among the alternative screen densities and scale the bitmaps as necessary. However, for the best experience on all types of devices, provide alternative drawables for all three types of density.

## How Android finds the best-matching resource

When you request a resource for which you provide alternatives, Android selects which alternative resource to use at runtime, depending on the current device configuration. To demonstrate how Android selects an alternative resource, assume the following drawable directories each contain different versions of the same images:  

```
drawable/
drawable-en/
drawable-fr-rCA/
drawable-en-port/
drawable-en-notouch-12key/
drawable-port-ldpi/
drawable-port-notouch-12key/
```

And assume the following is the device configuration:

Locale =`en-GB`  
Screen orientation =`port`  
Screen pixel density =`hdpi`  
Touchscreen type =`notouch`  
Primary text input method =`12key`

By comparing the device configuration to the available alternative resources, Android selects drawables from`drawable-en-port`.

The system arrives at its decision for which resources to use with the following logic:  
![](https://developer.android.com/static/images/resources/res-selection-flowchart.png)

**Figure 2.**Flowchart of how Android finds the best-matching resource.

1. Eliminate resource files that contradict the device configuration.The`drawable-fr-rCA/`directory is eliminated, because it contradicts the`en-GB`locale.

   ```
   drawable/
   drawable-en/
   drawable-fr-rCA/
   drawable-en-port/
   drawable-en-notouch-12key/
   drawable-port-ldpi/
   drawable-port-notouch-12key/
   ```

   **Exception:** Screen pixel density is the one qualifier that is not eliminated due to a contradiction. Even though the screen density of the device is hdpi,`drawable-port-ldpi/`isn't eliminated because every screen density is considered to be a match at this point. For information, see[Screen compatibility overview](https://developer.android.com/guide/practices/screens_support).
2. Find the next-highest-precedence qualifier in the list ([table 2](https://developer.android.com/guide/topics/resources/providing-resources#table2)). (Start with MCC.)
3. Do any of the resource directories include this qualifier?
   - If no, return to step two and look at the next qualifier. In this example, the answer is "no" until the language qualifier is reached.
   - If yes, continue to step four.
4. Eliminate resource directories that don't include this qualifier. In this example, the system next eliminates all the directories that don't include a language qualifier:  

   ```
   drawable/
   drawable-en/
   drawable-en-port/
   drawable-en-notouch-12key/
   drawable-port-ldpi/
   drawable-port-notouch-12key/
   ```

   **Exception:** If the qualifier in question is screen pixel density, Android selects the option that most closely matches the device screen density. In general, Android prefers scaling down a larger original image to scaling up a smaller original image. For more information, see[Screen compatibility overview](https://developer.android.com/guide/practices/screens_support).
5. Repeat steps two, three, and four until only one directory remains. In this example, screen orientation is the next qualifier for which there are any matches. So, resources that don't specify a screen orientation are eliminated:  

   ```
   drawable-en/
   drawable-en-port/
   drawable-en-notouch-12key/
   ```

   The remaining directory is`drawable-en-port`.

Though this procedure is executed for each resource requested, the system optimizes some aspects of it. One such optimization is that once the device configuration is known, it might eliminate alternative resources that can never match. For example, if the configuration language is English, then any resource directory that has a language qualifier set to something other than English is never included in the pool of resources checked (though a resource directory*without*the language qualifier is still included).

When selecting resources based on the screen size qualifiers, the system uses resources designed for a screen smaller than the current screen if there are no resources that better match. For example, a large-size screen uses normal-size screen resources if necessary.

However, if the only available resources are*larger* than the current screen, the system**doesn't** use them and your app crashes if no other resources match the device configuration. This happens, for example, if all layout resources are tagged with the`xlarge`qualifier, but the device is a normal-size screen.

**Note:** The*precedence* of the qualifier (in[table 2](https://developer.android.com/guide/topics/resources/providing-resources#table2)) is more important than the number of qualifiers that exactly match the device. In the preceding example, at step four the last choice on the list includes three qualifiers that exactly match the device (orientation, touchscreen type, and input method), while`drawable-en`has only one parameter that matches (language). However, language has a higher precedence than these other qualifiers, so`drawable-port-notouch-12key`is eliminated.