**Note:** With the release of Android 9.0 (API level 28) there is a new version of the support library called[AndroidX](https://developer.android.com/jetpack/androidx)which is part of[Jetpack](https://developer.android.com/jetpack). The AndroidX library contains the existing support library and also includes the latest Jetpack components.  

You can continue to use the support library. Historical artifacts (those versioned 27 and earlier, and packaged as`android.support.*`) will remain available on Google Maven. However, all new library development will occur in the[AndroidX](https://developer.android.com/jetpack/androidx)library.  

We recommend using the AndroidX libraries in all new projects. You should also consider[migrating](https://developer.android.com/jetpack/androidx/migrate)existing projects to AndroidX as well.

The Support Libraries provide a wide range of classes for building apps, from fundamental app components, to user interface widgets, to media handling, to TV app components. Many of the classes are backward compatible implementations, but some of them are new features in their own right.

This document provides an overview of the important categories of features available in the support library, and specific classes you should know about when building your app.

For information about how to add support library code to your app development project, see[Support Library Setup](https://developer.android.com/topic/libraries/support-library/setup.html). For information on how to include specific support library packages in your project, see[Support Library Packages](https://developer.android.com/topic/libraries/support-library/packages.html).

## App Components

These Support Library classes provide backward-compatible implementations of important, core platform features. These implementation typically extend earlier versions of the class to handle new methods and features added in more recent releases of the platform. Some of these classes are complete, static implementations of the framework APIs.

- Activities
  - [ActivityCompat](https://developer.android.com/reference/androidx/core/app/ActivityCompat)- Includes backward-compatible implementation for recent, key features of activities, such as a[Runtime Permissions](https://developer.android.com/about/versions/marshmallow/android-6.0-changes#behavior-runtime-permissions)and animation transitions.
  - [FragmentActivity](https://developer.android.com/reference/androidx/fragment/app/FragmentActivity)- Provides backward-compatible implementation for activities to use the support library versions of[Fragment](https://developer.android.com/reference/androidx/fragment/app/Fragment.html)and[Loader](https://developer.android.com/reference/androidx/loader/content/Loader.html)APIs.
  - [AppCompatActivity](https://developer.android.com/reference/androidx/appcompat/app/AppCompatActivity)- Provides Material color themes, widget tinting, and[app bar](https://developer.android.com/training/appbar/index.html)support to earlier devices. Use of this class requires that you use`Theme.AppCompat`themes for consistent visual presentation.
- [Fragment](https://developer.android.com/reference/androidx/fragment/app/Fragment)- Provides a stand-alone implementation of the framework[Fragment](https://developer.android.com/reference/android/app/Fragment)class. This class must be used with[FragmentActivity](https://developer.android.com/reference/androidx/fragment/app/FragmentActivity).
- [ContextCompat](https://developer.android.com/reference/androidx/core/content/ContextCompat)- Provides support for features introduced in more recent releases of the[Context](https://developer.android.com/reference/android/content/Context)class, including permissions support, file access, and color information.
- [IntentCompat](https://developer.android.com/reference/androidx/core/content/IntentCompat)- Provides support for features introduced in more recent releases of the[Intent](https://developer.android.com/reference/android/content/Intent)class, including methods for selecting and starting specific activities.
- [Loader](https://developer.android.com/reference/androidx/loader/content/Loader)- Provides a static implementation of the framework[Loader](https://developer.android.com/reference/android/content/Loader)class, and is the base class for the[AsyncTaskLoader](https://developer.android.com/reference/androidx/loader/content/AsyncTaskLoader)and[CursorLoader](https://developer.android.com/reference/androidx/loader/content/CursorLoader)support classes.
- [Preference](https://developer.android.com/reference/androidx/preference/Preference)- This class and its sub-classes provide implementations of app settings user interface in a backward-compatible way.
- [ContentResolverCompat](https://developer.android.com/reference/androidx/core/content/ContentResolverCompat)- Provides support for features introduced in more recent releases of the[ContentResolver](https://developer.android.com/reference/android/content/ContentResolver)class, specifically the[query()](https://developer.android.com/reference/androidx/core/content/ContentResolverCompat#query(android.content.ContentResolver, android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, android.support.v4.os.CancellationSignal))method with support for cancelling a query in progress.

## User Interface

These support library classes provide implementations of key user interface widgets and behaviors, and help you create more modern app interfaces on earlier devices. A few of these widgets are only available through the support library.

### General-purpose layout containers

These support classes provide user interface containers that can be adapted for different design use cases.

- [RecyclerView](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView)- Creates a layout for displaying long lists, using a strategy to avoid high memory consumption. This class allows you to create a limited window view into a larger data set, thus avoiding consuming large amounts of memory when displaying the list. For more information about using[RecyclerView](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView), see the[Recycler View](https://developer.android.com/guide/topics/ui/layout/recyclerview)guide.
- [ViewPager](https://developer.android.com/reference/androidx/viewpager/widget/ViewPager)- Provides a layout that allows the user to flip left and right through pages of data.
- [GridLayout](https://developer.android.com/reference/androidx/gridlayout/widget/GridLayout)- Provides a layout with its children in a rectangular grid, supporting arbitrary spans of contiguous cells and flexible space distribution. This class provides a backward compatible version of the[GridLayout](https://developer.android.com/reference/android/widget/GridLayout)class, introduced in Android 4.0 (API level 14).
- [PercentFrameLayout](https://developer.android.com/reference/androidx/percentlayout/widget/PercentFrameLayout)and[PercentRelativeLayout](https://developer.android.com/reference/androidx/percentlayout/widget/PercentRelativeLayout)- Provide layouts that support percentage based dimensions and margins for its child views and content.

**Note:** The[ViewPager](https://developer.android.com/reference/androidx/viewpager/widget/ViewPager),[RecyclerView](https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView),[PercentFrameLayout](https://developer.android.com/reference/androidx/percentlayout/widget/PercentFrameLayout)and[PercentRelativeLayout](https://developer.android.com/reference/androidx/percentlayout/widget/PercentRelativeLayout)classes are only available from the Support Libraries.

### Special-purpose layout containers

These support classes provide compatible implementations of specific layout patterns, such as drawer views that can be pulled from the edge of the screen, sliding panels, and nesting lists within lists.

- [DrawerLayout](https://developer.android.com/reference/androidx/drawerlayout/widget/DrawerLayout)- Creates a layout that allows for interactive[drawer views](https://developer.android.com/training/implementing-navigation/nav-drawer)to be pulled out from the edge of the view window.
- [SlidingPaneLayout](https://developer.android.com/reference/androidx/slidingpanelayout/widget/SlidingPaneLayout)- Provides a horizontal, multi-pane layout for use at the top level of an app user interface for creating layouts that can smoothly adapt across many different screen sizes, expanding on larger screens and collapsing to fit on smaller screens.
- [NestedScrollView](https://developer.android.com/reference/androidx/core/widget/NestedScrollView)- A scrolling layout that supports nesting of other scrolling views, allowing you to create lists, with items containing an additional, child lists. These nested lists can contain items that scroll horizontally or vertically, separately from the parent list.
- [SwipeRefreshLayout](https://developer.android.com/reference/androidx/swiperefreshlayout/widget/SwipeRefreshLayout)- Provides a layout to support refreshing data for lists or other layout with a finger swipe gesture.

### Views, dialogs, and widgets

The support libraries provide a number of classes for displaying content and providing user interaction elements in a layout.

- [CardView](https://developer.android.com/reference/androidx/cardview/widget/CardView)- A support library custom class for creating Material Design style display cards. This class is based on FrameLayout with rounded corners and a drop shadow.
- [AppCompatDialogFragment](https://developer.android.com/reference/androidx/appcompat/app/AppCompatDialogFragment)- Provides a consistently styled dialogs by extending[DialogFragment](https://developer.android.com/reference/androidx/fragment/app/DialogFragment)and using[AppCompatDialog](https://developer.android.com/reference/androidx/appcompat/app/AppCompatDialog).
- [NotificationCompat](https://developer.android.com/reference/androidx/core/app/NotificationCompat)- Provides support for newer notification styles in a backward compatible way.
- [SearchView](https://developer.android.com/reference/androidx/appcompat/widget/SearchView)- Provides a class for the user to enter a search query and submit a request to a search provider, which is primarily intended for use in an app bar.

## Material Design

The support libraries provide a number of classes for implementing Material Design user interface recommendations.

- [CoordinatorLayout](https://developer.android.com/reference/androidx/coordinatorlayout/widget/CoordinatorLayout)- Provides a top-level container for layouts incorporating Material Design components and behavior. This class can also be used as a container for specific interaction with one or more child views.
- [AppBarLayout](https://developer.android.com/reference/com/google/android/material/appbar/AppBarLayout)- Provides an implementation of many of the scrolling features of Material Design's[app bar concept](http://www.google.com/design/spec/layout/structure.html#structure-app-bar).
- [FloatingActionButton](https://developer.android.com/reference/com/google/android/material/floatingactionbutton/FloatingActionButton)- Creates floating button for displaying a special type of promoted action. This Material Design user interface element is shown as a circled icon floating above the app user interface. For more information, see[Add a Floating Action Button](https://developer.android.com/guide/topics/ui/floating-action-button).
- [DrawerLayout](https://developer.android.com/reference/androidx/drawerlayout/widget/DrawerLayout)- Creates a navigation drawer---a UI panel that shows your app's main navigation menu. It appears when the user swipes a finger from the left edge of the screen or taps the drawer icon in the app bar. For more information, see[Create a Navigation Drawer](https://developer.android.com/training/implementing-navigation/nav-drawer).
- [TabLayout](https://developer.android.com/reference/com/google/android/material/tabs/TabLayout)- Provides a layout for displaying tabbed pages. This widget is designed for use with the[ViewPager](https://developer.android.com/reference/androidx/viewpager/widget/ViewPager)class.
- [Snackbar](https://developer.android.com/reference/com/google/android/material/snackbar/Snackbar)- Provides a widget for displaying lightweight feedback about an operation using the[snackbar pop-up](https://developer.android.com/training/snackbar).

## Graphics

The[android.support.graphics.drawable](https://developer.android.com/reference/android/support/graphics/drawable/package-summary)package provides support for[vector drawables](https://www.youtube.com/watch?v=wlFVIIstKmA). By using vector drawables, you can replace multiple PNG assets with a single vector graphic, defined in XML.

[VectorDrawableCompat](https://developer.android.com/reference/androidx/vectordrawable/graphics/drawable/VectorDrawableCompat)provides support for vector drawables on API level 9 and above.[AnimatedVectorDrawableCompat](https://developer.android.com/reference/androidx/vectordrawable/graphics/drawable/AnimatedVectorDrawableCompat)provides support for animated vector drawables on API level 11 and above.

## Accessibility

The[android.support.v4.view.accessibility](https://developer.android.com/reference/android/support/v4/view/accessibility/package-summary)package provides compatibility classes for implementing accessibility features introduced in API level 14 and later, which allow accessibility services to observe and identify user interaction with items displayed on screen.

- [ExploreByTouchHelper](https://developer.android.com/reference/androidx/customview/widget/ExploreByTouchHelper)- Provides accessibility support in a custom[View](https://developer.android.com/reference/android/view/View.html)that represent a collection of view-like logical items.

## Media Playback

The Android Support Library provides a backport of the[media router](https://developer.android.com/guide/topics/media/mediarouter.html)functionality to devices running versions of the platform earlier than Android 4.1 (API level 16). These classes allow control of media playback across connected Android devices:

- [MediaRouter](https://developer.android.com/reference/androidx/mediarouter/media/MediaRouter)- Enables applications to control the routing of media channels and streams from the current device to external speakers and destination devices.
- [MediaControllerCompat](https://developer.android.com/reference/android/support/v4/media/session/MediaControllerCompat)- Allows an app to interact with an ongoing media session. Apps can provide media control buttons through this mechanism and send other playback commands to the session.
- [MediaSessionCompat](https://developer.android.com/reference/android/support/v4/media/session/MediaSessionCompat)- Provides a remote control interface for media playback, enabling interaction with media controllers, volume keys, media buttons, and transport controls in other apps or on separate devices.

## TV Apps

The Android SDK provides libraries to support form factors such as large screens and their associated controllers. An app can depend on the appropriate support library to provide functionality across a wide range of platform versions, and can provide content on external screens, speakers, and other destination devices.

- [android.support.v17.leanback](https://developer.android.com/reference/android/support/v17/leanback/package-summary.html).\* packages

## Wear Apps

The Android SDK provides libraries to support watches. These libraries provide functionality to apps that is available to users whenever they are wearing a watch.

- [android.support.wear](https://developer.android.com/reference/android/support/wear/package-summary.html).\* packages

## Utilities

The Android Support Library offers a number of features that are not built into the framework. These libraries offer a range of utilities that apps can use.

- [android.support.v4.util](https://developer.android.com/reference/android/support/v4/util/package-summary)package