Package io.flutter.embedding.android

## Class FlutterFragment

- java.lang.Object
- - androidx.fragment.app.Fragment
  - - io.flutter.embedding.android.FlutterFragment

- All Implemented Interfaces:
    `ComponentCallbacks`, `ComponentCallbacks2`, `View.OnCreateContextMenuListener`, `androidx.lifecycle.LifecycleOwner`, `androidx.lifecycle.ViewModelStoreOwner`, `androidx.savedstate.SavedStateRegistryOwner`, `FlutterEngineConfigurator`, `FlutterEngineProvider`, `SplashScreenProvider`, `PlatformPlugin.PlatformPluginDelegate`

      public class FlutterFragment
      extends androidx.fragment.app.Fragment
      implements ComponentCallbacks2

  `Fragment` which displays a Flutter UI that takes up all available `Fragment` space.

  Using a `FlutterFragment` requires forwarding a number of calls from an `Activity` to ensure that the internal Flutter app behaves as expected:

  1. `onPostResume()`
  2. `onBackPressed()`
  3. `onRequestPermissionsResult(int, String[], int[])`
  4. `onNewIntent(Intent)`
  5. `onUserLeaveHint()`
  `onBackPressed()` does not need to be called through if the fragment is constructed by one of the builders with `shouldAutomaticallyHandleOnBackPressed(true)`.

  Additionally, when starting an `Activity` for a result from this `Fragment`, be sure to invoke `Fragment.startActivityForResult(Intent, int)` rather than `Activity.startActivityForResult(Intent, int)`. If the `Activity` version of the method is invoked then this `Fragment` will never receive its `Fragment.onActivityResult(int, int, Intent)` callback.

  If convenient, consider using a `FlutterActivity` instead of a `FlutterFragment` to avoid the work of forwarding calls.

  `FlutterFragment` supports the use of an existing, cached `FlutterEngine`. To use a cached `FlutterEngine`, ensure that the `FlutterEngine` is stored in `FlutterEngineCache` and then use `withCachedEngine(String)` to build a `FlutterFragment` with the cached `FlutterEngine`'s ID.

  It is generally recommended to use a cached `FlutterEngine` to avoid a momentary delay when initializing a new `FlutterEngine`. The two exceptions to using a cached `FlutterEngine` are:

  - When `FlutterFragment` is in the first `Activity` displayed by the app, because pre-warming a `FlutterEngine` would have no impact in this situation.
  - When you are unsure when/if you will need to display a Flutter experience.

  The following illustrates how to pre-warm and cache a `FlutterEngine`:

       // Create and pre-warm a FlutterEngine.
       FlutterEngine flutterEngine = new FlutterEngine(context);
       flutterEngine
         .getDartExecutor()
         .executeDartEntrypoint(DartEntrypoint.createDefault());

       // Cache the pre-warmed FlutterEngine in the FlutterEngineCache.
       FlutterEngineCache.getInstance().put("my_engine", flutterEngine);

  If Flutter is needed in a location that can only use a `View`, consider using a `FlutterView`. Using a `FlutterView` requires forwarding some calls from an `Activity`, as well as forwarding lifecycle calls from an `Activity` or a `Fragment`.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class | Description
    --- | --- | ---
    `static class` | `FlutterFragment.CachedEngineFragmentBuilder` | Builder that creates a new `FlutterFragment` that uses a cached `FlutterEngine` with `arguments` that correspond to the values set on this `Builder`.
    `static class` | `FlutterFragment.NewEngineFragmentBuilder` | Builder that creates a new `FlutterFragment` with `arguments` that correspond to the values set on this `NewEngineFragmentBuilder`.

    - ### Nested classes/interfaces inherited from class androidx.fragment.app.Fragment

      `androidx.fragment.app.Fragment.InstantiationException, androidx.fragment.app.Fragment.SavedState`

  - ### Field Summary

    Fields
    Modifier and Type | Field | Description
    --- | --- | ---
    `protected static String` | `ARG_APP_BUNDLE_PATH` | Path to Flutter's Dart code.
    `protected static String` | `ARG_CACHED_ENGINE_ID` | The ID of a `FlutterEngine` cached in `FlutterEngineCache` that will be used within the created `FlutterFragment`.
    `protected static String` | `ARG_DART_ENTRYPOINT` | The Dart entrypoint method name that is executed upon initialization.
    `protected static String` | `ARG_DART_ENTRYPOINT_ARGS` | The Dart entrypoint arguments that is executed upon initialization.
    `protected static String` | `ARG_DART_ENTRYPOINT_URI` | The Dart entrypoint method's URI that is executed upon initialization.
    `protected static String` | `ARG_DESTROY_ENGINE_WITH_FRAGMENT` | True if the `FlutterEngine` in the created `FlutterFragment` should be destroyed when the `FlutterFragment` is destroyed, false if the `FlutterEngine` should outlive the `FlutterFragment`.
    `protected static String` | `ARG_ENABLE_STATE_RESTORATION` | True if the framework state in the engine attached to this engine should be stored and restored when this fragment is created and destroyed.
    `protected static String` | `ARG_FLUTTER_INITIALIZATION_ARGS` | Flutter shell arguments.
    `protected static String` | `ARG_FLUTTERVIEW_RENDER_MODE` | `RenderMode` to be used for the `FlutterView` in this `FlutterFragment`
    `protected static String` | `ARG_FLUTTERVIEW_TRANSPARENCY_MODE` | `TransparencyMode` to be used for the `FlutterView` in this `FlutterFragment`
    `protected static String` | `ARG_HANDLE_DEEPLINKING` | Whether the activity delegate should handle the deeplinking request.
    `protected static String` | `ARG_INITIAL_ROUTE` | Initial Flutter route that is rendered in a Navigator widget.
    `protected static String` | `ARG_SHOULD_ATTACH_ENGINE_TO_ACTIVITY` | See `shouldAttachEngineToActivity()`.
    `protected static String` | `ARG_SHOULD_AUTOMATICALLY_HANDLE_ON_BACK_PRESSED` | True if the fragment should receive `onBackPressed()` events automatically, without requiring an explicit activity call through.
    `protected static String` | `ARG_SHOULD_DELAY_FIRST_ANDROID_VIEW_DRAW` | Whether to delay the Android drawing pass till after the Flutter UI has been displayed.
    `static int` | `FLUTTER_VIEW_ID` | The ID of the `FlutterView` created by this activity.

    - ### Fields inherited from interface android.content.ComponentCallbacks2

      `TRIM_MEMORY_BACKGROUND, TRIM_MEMORY_COMPLETE, TRIM_MEMORY_MODERATE, TRIM_MEMORY_RUNNING_CRITICAL, TRIM_MEMORY_RUNNING_LOW, TRIM_MEMORY_RUNNING_MODERATE, TRIM_MEMORY_UI_HIDDEN`

  - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `FlutterFragment()` |

  - ### Method Summary

    All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `cleanUpFlutterEngine​(FlutterEngine flutterEngine)` | Hook for the host to cleanup references that were established in `configureFlutterEngine(FlutterEngine)` before the host is destroyed or detached.
    `void` | `configureFlutterEngine​(FlutterEngine flutterEngine)` | Configures a `FlutterEngine` after its creation.
    `static FlutterFragment` | `createDefault()` | Creates a `FlutterFragment` with a default configuration.
    `void` | `detachFromFlutterEngine()` |
    `Activity` | `getActivity()` | Returns the host `Activity` or the `Activity` that is currently attached to the host `Fragment`.
    `String` | `getAppBundlePath()` | A custom path to the bundle that contains this Flutter app's resources, e.g., Dart code snapshots.
    `String` | `getCachedEngineId()` | Returns the ID of a statically cached `FlutterEngine` to use within this `FlutterFragment`, or `null` if this `FlutterFragment` does not want to use a cached `FlutterEngine`.
    `Context` | `getContext()` | Returns the `Context` that backs the host `Activity` or `Fragment`.
    `List<String>` | `getDartEntrypointArgs()` | The Dart entrypoint arguments will be passed as a list of string to Dart's entrypoint function.
    `String` | `getDartEntrypointFunctionName()` | Returns the name of the Dart method that this `FlutterFragment` should execute to start a Flutter app.
    `String` | `getDartEntrypointLibraryUri()` | Returns the library URI of the Dart method that this `FlutterFragment` should execute to start a Flutter app.
    `ExclusiveAppComponent<Activity>` | `getExclusiveAppComponent()` | Returns the Android App Component exclusively attached to `FlutterEngine`.
    `FlutterEngine` | `getFlutterEngine()` | Hook for subclasses to obtain a reference to the `FlutterEngine` that is owned by this `FlutterActivity`.
    `FlutterShellArgs` | `getFlutterShellArgs()` | `FlutterActivityAndFragmentDelegate.Host` method that is used by `FlutterActivityAndFragmentDelegate` to obtain Flutter shell arguments when initializing Flutter.
    `String` | `getInitialRoute()` | Returns the initial route that should be rendered within Flutter, once the Flutter app starts.
    `androidx.lifecycle.Lifecycle` | `getLifecycle()` | Returns the `Lifecycle` that backs the host `Activity` or `Fragment`.
    `RenderMode` | `getRenderMode()` | Returns the desired `RenderMode` for the `FlutterView` displayed in this `FlutterFragment`.
    `TransparencyMode` | `getTransparencyMode()` | Returns the desired `TransparencyMode` for the `FlutterView` displayed in this `FlutterFragment`.
    `void` | `onActivityResult​(int requestCode, int resultCode, Intent data)` | A result has been returned after an invocation of `Fragment.startActivityForResult(Intent, int)`.
    `void` | `onAttach​(Context context)` |
    `void` | `onBackPressed()` | The hardware back button was pressed.
    `void` | `onCreate​(Bundle savedInstanceState)` |
    `View` | `onCreateView​(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)` |
    `void` | `onDestroyView()` |
    `void` | `onDetach()` |
    `void` | `onFlutterSurfaceViewCreated​(FlutterSurfaceView flutterSurfaceView)` |
    `void` | `onFlutterTextureViewCreated​(FlutterTextureView flutterTextureView)` |
    `void` | `onFlutterUiDisplayed()` | Invoked after the `FlutterView` within this `FlutterFragment` starts rendering pixels to the screen.
    `void` | `onFlutterUiNoLongerDisplayed()` | Invoked after the `FlutterView` within this `FlutterFragment` stops rendering pixels to the screen.
    `void` | `onLowMemory()` | Callback invoked when memory is low.
    `void` | `onNewIntent​(Intent intent)` | A new Intent was received by the `Activity` that currently owns this `Fragment`.
    `void` | `onPause()` |
    `void` | `onPostResume()` |
    `void` | `onRequestPermissionsResult​(int requestCode, String[] permissions, int[] grantResults)` | The result of a permission request has been received.
    `void` | `onResume()` |
    `void` | `onSaveInstanceState​(Bundle outState)` |
    `void` | `onStart()` |
    `void` | `onStop()` |
    `void` | `onTrimMemory​(int level)` | Callback invoked when memory is low.
    `void` | `onUserLeaveHint()` | The `Activity` that owns this `Fragment` is about to go to the background as the result of a user's choice/action, i.e., not as the result of an OS decision.
    `boolean` | `popSystemNavigator()` | Allow implementer to customize the behavior needed when the Flutter framework calls to pop the Android-side navigation stack.
    `FlutterEngine` | `provideFlutterEngine​(Context context)` | Hook for subclasses to return a `FlutterEngine` with whatever configuration is desired.
    `PlatformPlugin` | `providePlatformPlugin​(Activity activity, FlutterEngine flutterEngine)` |
    `SplashScreen` | `provideSplashScreen()` | Provides a `SplashScreen` to display while Flutter initializes and renders its first frame.
    `boolean` | `shouldAttachEngineToActivity()` | See `shouldAttachEngineToActivity()` and `shouldAttachEngineToActivity()`.
    `boolean` | `shouldDestroyEngineWithHost()` | Returns false if the `FlutterEngine` within this `FlutterFragment` should outlive the `FlutterFragment`, itself.
    `boolean` | `shouldDispatchAppLifecycleState()` | Give the host application a chance to take control of the app lifecycle events.
    `boolean` | `shouldHandleDeeplinking()` | Whether to handle the deeplinking from the `Intent` automatically if the `getInitialRoute` returns null.
    `boolean` | `shouldRestoreAndSaveState()` |
    `void` | `updateSystemUiOverlays()` |
    `static FlutterFragment.CachedEngineFragmentBuilder` | `withCachedEngine​(String engineId)` | Returns a `FlutterFragment.CachedEngineFragmentBuilder` to create a `FlutterFragment` with a cached `FlutterEngine` in `FlutterEngineCache`.
    `static FlutterFragment.NewEngineFragmentBuilder` | `withNewEngine()` | Returns a `FlutterFragment.NewEngineFragmentBuilder` to create a `FlutterFragment` with a new `FlutterEngine` and a desired engine configuration.

    - ### Methods inherited from class androidx.fragment.app.Fragment

      `dump, equals, getActivity, getAllowEnterTransitionOverlap, getAllowReturnTransitionOverlap, getArguments, getChildFragmentManager, getContext, getEnterTransition, getExitTransition, getFragmentManager, getHost, getId, getLayoutInflater, getLayoutInflater, getLifecycle, getLoaderManager, getParentFragment, getReenterTransition, getResources, getRetainInstance, getReturnTransition, getSavedStateRegistry, getSharedElementEnterTransition, getSharedElementReturnTransition, getString, getString, getTag, getTargetFragment, getTargetRequestCode, getText, getUserVisibleHint, getView, getViewLifecycleOwner, getViewLifecycleOwnerLiveData, getViewModelStore, hashCode, hasOptionsMenu, instantiate, instantiate, isAdded, isDetached, isHidden, isInLayout, isMenuVisible, isRemoving, isResumed, isStateSaved, isVisible, onActivityCreated, onAttach, onAttachFragment, onConfigurationChanged, onContextItemSelected, onCreateAnimation, onCreateAnimator, onCreateContextMenu, onCreateOptionsMenu, onDestroy, onDestroyOptionsMenu, onGetLayoutInflater, onHiddenChanged, onInflate, onInflate, onMultiWindowModeChanged, onOptionsItemSelected, onOptionsMenuClosed, onPictureInPictureModeChanged, onPrepareOptionsMenu, onPrimaryNavigationFragmentChanged, onViewCreated, onViewStateRestored, postponeEnterTransition, postponeEnterTransition, registerForContextMenu, requestPermissions, requireActivity, requireArguments, requireContext, requireFragmentManager, requireHost, requireParentFragment, requireView, setAllowEnterTransitionOverlap, setAllowReturnTransitionOverlap, setArguments, setEnterSharedElementCallback, setEnterTransition, setExitSharedElementCallback, setExitTransition, setHasOptionsMenu, setInitialSavedState, setMenuVisibility, setReenterTransition, setRetainInstance, setReturnTransition, setSharedElementEnterTransition, setSharedElementReturnTransition, setTargetFragment, setUserVisibleHint, shouldShowRequestPermissionRationale, startActivity, startActivity, startActivityForResult, startActivityForResult, startIntentSenderForResult, startPostponedEnterTransition, toString, unregisterForContextMenu`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface android.content.ComponentCallbacks

      `onConfigurationChanged`

- - ### Field Detail

    - #### FLUTTER_VIEW_ID

          public static final int FLUTTER_VIEW_ID

      The ID of the `FlutterView` created by this activity.

      This ID can be used to lookup `FlutterView` in the Android view hierarchy. For more, see `View.findViewById(int)`.

    - #### ARG_DART_ENTRYPOINT

          protected static final String ARG_DART_ENTRYPOINT

      The Dart entrypoint method name that is executed upon initialization.
      See Also:
        Constant Field Values

    - #### ARG_DART_ENTRYPOINT_URI

          protected static final String ARG_DART_ENTRYPOINT_URI

      The Dart entrypoint method's URI that is executed upon initialization.
      See Also:
        Constant Field Values

    - #### ARG_DART_ENTRYPOINT_ARGS

          protected static final String ARG_DART_ENTRYPOINT_ARGS

      The Dart entrypoint arguments that is executed upon initialization.
      See Also:
        Constant Field Values

    - #### ARG_INITIAL_ROUTE

          protected static final String ARG_INITIAL_ROUTE

      Initial Flutter route that is rendered in a Navigator widget.
      See Also:
        Constant Field Values

    - #### ARG_HANDLE_DEEPLINKING

          protected static final String ARG_HANDLE_DEEPLINKING

      Whether the activity delegate should handle the deeplinking request.
      See Also:
        Constant Field Values

    - #### ARG_APP_BUNDLE_PATH

          protected static final String ARG_APP_BUNDLE_PATH

      Path to Flutter's Dart code.
      See Also:
        Constant Field Values

    - #### ARG_SHOULD_DELAY_FIRST_ANDROID_VIEW_DRAW

          protected static final String ARG_SHOULD_DELAY_FIRST_ANDROID_VIEW_DRAW

      Whether to delay the Android drawing pass till after the Flutter UI has been displayed.
      See Also:
        Constant Field Values

    - #### ARG_FLUTTER_INITIALIZATION_ARGS

          protected static final String ARG_FLUTTER_INITIALIZATION_ARGS

      Flutter shell arguments.
      See Also:
        Constant Field Values

    - #### ARG_FLUTTERVIEW_RENDER_MODE

          protected static final String ARG_FLUTTERVIEW_RENDER_MODE

      `RenderMode` to be used for the `FlutterView` in this `FlutterFragment`
      See Also:
        Constant Field Values

    - #### ARG_FLUTTERVIEW_TRANSPARENCY_MODE

          protected static final String ARG_FLUTTERVIEW_TRANSPARENCY_MODE

      `TransparencyMode` to be used for the `FlutterView` in this `FlutterFragment`
      See Also:
        Constant Field Values

    - #### ARG_SHOULD_ATTACH_ENGINE_TO_ACTIVITY

          protected static final String ARG_SHOULD_ATTACH_ENGINE_TO_ACTIVITY

      See `shouldAttachEngineToActivity()`.
      See Also:
        Constant Field Values

    - #### ARG_CACHED_ENGINE_ID

          protected static final String ARG_CACHED_ENGINE_ID

      The ID of a `FlutterEngine` cached in `FlutterEngineCache` that will be used within the created `FlutterFragment`.
      See Also:
        Constant Field Values

    - #### ARG_DESTROY_ENGINE_WITH_FRAGMENT

          protected static final String ARG_DESTROY_ENGINE_WITH_FRAGMENT

      True if the `FlutterEngine` in the created `FlutterFragment` should be destroyed when the `FlutterFragment` is destroyed, false if the `FlutterEngine` should outlive the `FlutterFragment`.
      See Also:
        Constant Field Values

    - #### ARG_ENABLE_STATE_RESTORATION

          protected static final String ARG_ENABLE_STATE_RESTORATION

      True if the framework state in the engine attached to this engine should be stored and restored when this fragment is created and destroyed.
      See Also:
        Constant Field Values

    - #### ARG_SHOULD_AUTOMATICALLY_HANDLE_ON_BACK_PRESSED

          protected static final String ARG_SHOULD_AUTOMATICALLY_HANDLE_ON_BACK_PRESSED

      True if the fragment should receive `onBackPressed()` events automatically, without requiring an explicit activity call through.
      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### FlutterFragment

          public FlutterFragment()

  - ### Method Detail

    - #### createDefault

          @NonNull
          public static FlutterFragment createDefault()

      Creates a `FlutterFragment` with a default configuration.

      `FlutterFragment`'s default configuration creates a new `FlutterEngine` within the `FlutterFragment` and uses the following settings:

      - Dart entrypoint: "main"
      - Initial route: "/"
      - Render mode: surface
      - Transparency mode: transparent

      To use a new `FlutterEngine` with different settings, use `withNewEngine()`.

      To use a cached `FlutterEngine` instead of creating a new one, use `withCachedEngine(String)`.

    - #### withNewEngine

          @NonNull
          public static FlutterFragment.NewEngineFragmentBuilder withNewEngine()

      Returns a `FlutterFragment.NewEngineFragmentBuilder` to create a `FlutterFragment` with a new `FlutterEngine` and a desired engine configuration.

    - #### withCachedEngine

          @NonNull
          public static FlutterFragment.CachedEngineFragmentBuilder withCachedEngine​(@NonNull
                                                                                     String engineId)

      Returns a `FlutterFragment.CachedEngineFragmentBuilder` to create a `FlutterFragment` with a cached `FlutterEngine` in `FlutterEngineCache`.

      An `IllegalStateException` will be thrown during the lifecycle of the `FlutterFragment` if a cached `FlutterEngine` is requested but does not exist in the cache.

      To create a `FlutterFragment` that uses a new `FlutterEngine`, use `createDefault()` or `withNewEngine()`.

    - #### getExclusiveAppComponent

          public ExclusiveAppComponent<Activity> getExclusiveAppComponent()

      Returns the Android App Component exclusively attached to `FlutterEngine`.

    - #### onAttach

          public void onAttach​(@NonNull
                               Context context)

      Overrides:
        `onAttach` in class `androidx.fragment.app.Fragment`

    - #### onCreate

          public void onCreate​(@Nullable
                               Bundle savedInstanceState)

      Overrides:
        `onCreate` in class `androidx.fragment.app.Fragment`

    - #### onCreateView

          @Nullable
          public View onCreateView​(LayoutInflater inflater,
                                   @Nullable
                                   ViewGroup container,
                                   @Nullable
                                   Bundle savedInstanceState)

      Overrides:
        `onCreateView` in class `androidx.fragment.app.Fragment`

    - #### onStart

          public void onStart()

      Overrides:
        `onStart` in class `androidx.fragment.app.Fragment`

    - #### onResume

          public void onResume()

      Overrides:
        `onResume` in class `androidx.fragment.app.Fragment`

    - #### onPostResume

          public void onPostResume()

    - #### onPause

          public void onPause()

      Overrides:
        `onPause` in class `androidx.fragment.app.Fragment`

    - #### onStop

          public void onStop()

      Overrides:
        `onStop` in class `androidx.fragment.app.Fragment`

    - #### onDestroyView

          public void onDestroyView()

      Overrides:
        `onDestroyView` in class `androidx.fragment.app.Fragment`

    - #### onSaveInstanceState

          public void onSaveInstanceState​(Bundle outState)

      Overrides:
        `onSaveInstanceState` in class `androidx.fragment.app.Fragment`

    - #### detachFromFlutterEngine

          public void detachFromFlutterEngine()

    - #### onDetach

          public void onDetach()

      Overrides:
        `onDetach` in class `androidx.fragment.app.Fragment`

    - #### onRequestPermissionsResult

          public void onRequestPermissionsResult​(int requestCode,
                                                 @NonNull
                                                 String[] permissions,
                                                 @NonNull
                                                 int[] grantResults)

      The result of a permission request has been received.

      See `Activity.onRequestPermissionsResult(int, String[], int[])`

      Overrides:
        `onRequestPermissionsResult` in class `androidx.fragment.app.Fragment`
      Parameters:
        `requestCode` - identifier passed with the initial permission request
        `permissions` - permissions that were requested
        `grantResults` - permission grants or denials

    - #### onNewIntent

          public void onNewIntent​(@NonNull
                                  Intent intent)

      A new Intent was received by the `Activity` that currently owns this `Fragment`.

      See `Activity.onNewIntent(Intent)`

      Parameters:
        `intent` - new Intent

    - #### onBackPressed

          public void onBackPressed()

      The hardware back button was pressed.

      If the fragment uses `shouldAutomaticallyHandleOnBackPressed(true)`, this method should not be called through. It will be called automatically instead.

      See `Activity.onBackPressed()`

    - #### onActivityResult

          public void onActivityResult​(int requestCode,
                                       int resultCode,
                                       Intent data)

      A result has been returned after an invocation of `Fragment.startActivityForResult(Intent, int)`.

      Overrides:
        `onActivityResult` in class `androidx.fragment.app.Fragment`
      Parameters:
        `requestCode` - request code sent with `Fragment.startActivityForResult(Intent, int)`
        `resultCode` - code representing the result of the `Activity` that was launched
        `data` - any corresponding return data, held within an `Intent`

    - #### onUserLeaveHint

          public void onUserLeaveHint()

      The `Activity` that owns this `Fragment` is about to go to the background as the result of a user's choice/action, i.e., not as the result of an OS decision.

      See `Activity.onUserLeaveHint()`

    - #### onTrimMemory

          public void onTrimMemory​(int level)

      Callback invoked when memory is low.

      This implementation forwards a memory pressure warning to the running Flutter app.

      Specified by:
        `onTrimMemory` in interface `ComponentCallbacks2`
      Parameters:
        `level` - level

    - #### onLowMemory

          public void onLowMemory()

      Callback invoked when memory is low.

      This implementation forwards a memory pressure warning to the running Flutter app.

      Specified by:
        `onLowMemory` in interface `ComponentCallbacks`
      Overrides:
        `onLowMemory` in class `androidx.fragment.app.Fragment`

    - #### getFlutterShellArgs

          @NonNull
          public FlutterShellArgs getFlutterShellArgs()

      `FlutterActivityAndFragmentDelegate.Host` method that is used by `FlutterActivityAndFragmentDelegate` to obtain Flutter shell arguments when initializing Flutter.

    - #### getCachedEngineId

          @Nullable
          public String getCachedEngineId()

      Returns the ID of a statically cached `FlutterEngine` to use within this `FlutterFragment`, or `null` if this `FlutterFragment` does not want to use a cached `FlutterEngine`.

    - #### shouldDestroyEngineWithHost

          public boolean shouldDestroyEngineWithHost()

      Returns false if the `FlutterEngine` within this `FlutterFragment` should outlive the `FlutterFragment`, itself.

      Defaults to true if no custom `is provided`, false if a custom `FlutterEngine` is provided.

    - #### getDartEntrypointFunctionName

          @NonNull
          public String getDartEntrypointFunctionName()

      Returns the name of the Dart method that this `FlutterFragment` should execute to start a Flutter app.

      Defaults to "main".

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### getDartEntrypointArgs

          @Nullable
          public List<String> getDartEntrypointArgs()

      The Dart entrypoint arguments will be passed as a list of string to Dart's entrypoint function.

      A value of null means do not pass any arguments to Dart's entrypoint function.

      Subclasses may override this method to directly control the Dart entrypoint arguments.

    - #### getDartEntrypointLibraryUri

          @Nullable
          public String getDartEntrypointLibraryUri()

      Returns the library URI of the Dart method that this `FlutterFragment` should execute to start a Flutter app.

      Defaults to null (example value: "package:foo/bar.dart").

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### getAppBundlePath

          @NonNull
          public String getAppBundlePath()

      A custom path to the bundle that contains this Flutter app's resources, e.g., Dart code snapshots.

      When unspecified, the value is null, which defaults to the app bundle path defined in `FlutterLoader.findAppBundlePath()`.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### getInitialRoute

          @Nullable
          public String getInitialRoute()

      Returns the initial route that should be rendered within Flutter, once the Flutter app starts.

      Defaults to `null`, which signifies a route of "/" in Flutter.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### getRenderMode

          @NonNull
          public RenderMode getRenderMode()

      Returns the desired `RenderMode` for the `FlutterView` displayed in this `FlutterFragment`.

      Defaults to `RenderMode.surface`.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### getTransparencyMode

          @NonNull
          public TransparencyMode getTransparencyMode()

      Returns the desired `TransparencyMode` for the `FlutterView` displayed in this `FlutterFragment`.

      Defaults to `TransparencyMode.transparent`.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### provideSplashScreen

          @Nullable
          public SplashScreen provideSplashScreen()

      Description copied from interface: `SplashScreenProvider`
      Provides a `SplashScreen` to display while Flutter initializes and renders its first frame.
      Specified by:
        `provideSplashScreen` in interface `SplashScreenProvider`
      Returns:
        The splash screen.

    - #### provideFlutterEngine

          @Nullable
          public FlutterEngine provideFlutterEngine​(@NonNull
                                                    Context context)

      Hook for subclasses to return a `FlutterEngine` with whatever configuration is desired.

      By default this method defers to this `FlutterFragment`'s surrounding `Activity`, if that `Activity` implements `FlutterEngineProvider`. If this method is overridden, the surrounding `Activity` will no longer be given an opportunity to provide a `FlutterEngine`, unless the subclass explicitly implements that behavior.

      Consider returning a cached `FlutterEngine` instance from this method to avoid the typical warm-up time that a new `FlutterEngine` instance requires.

      If null is returned then a new default `FlutterEngine` will be created to back this `FlutterFragment`.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

      Specified by:
        `provideFlutterEngine` in interface `FlutterEngineProvider`
      Parameters:
        `context` - The current context. e.g. An activity.
      Returns:
        The Flutter engine.

    - #### getFlutterEngine

          @Nullable
          public FlutterEngine getFlutterEngine()

      Hook for subclasses to obtain a reference to the `FlutterEngine` that is owned by this `FlutterActivity`.

    - #### providePlatformPlugin

          @Nullable
          public PlatformPlugin providePlatformPlugin​(@Nullable
                                                      Activity activity,
                                                      @NonNull
                                                      FlutterEngine flutterEngine)

    - #### configureFlutterEngine

          public void configureFlutterEngine​(@NonNull
                                             FlutterEngine flutterEngine)

      Configures a `FlutterEngine` after its creation.

      This method is called after `provideFlutterEngine(Context)`, and after the given `FlutterEngine` has been attached to the owning `FragmentActivity`. See `ActivityControlSurface.attachToActivity( ExclusiveAppComponent, Lifecycle)`.

      It is possible that the owning `FragmentActivity` opted not to connect itself as an `ActivityControlSurface`. In that case, any configuration, e.g., plugins, must not expect or depend upon an available `Activity` at the time that this method is invoked.

      The default behavior of this method is to defer to the owning `FragmentActivity` as a `FlutterEngineConfigurator`. Subclasses can override this method if the subclass needs to override the `FragmentActivity`'s behavior, or add to it.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

      Specified by:
        `configureFlutterEngine` in interface `FlutterEngineConfigurator`
      Parameters:
        `flutterEngine` - The Flutter engine.

    - #### cleanUpFlutterEngine

          public void cleanUpFlutterEngine​(@NonNull
                                           FlutterEngine flutterEngine)

      Hook for the host to cleanup references that were established in `configureFlutterEngine(FlutterEngine)` before the host is destroyed or detached.

      This method is called in `onDetach()`.

      Specified by:
        `cleanUpFlutterEngine` in interface `FlutterEngineConfigurator`
      Parameters:
        `flutterEngine` - The Flutter engine.

    - #### shouldAttachEngineToActivity

          public boolean shouldAttachEngineToActivity()

      See `shouldAttachEngineToActivity()` and `shouldAttachEngineToActivity()`.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate`

    - #### shouldHandleDeeplinking

          public boolean shouldHandleDeeplinking()

      Whether to handle the deeplinking from the `Intent` automatically if the `getInitialRoute` returns null.

    - #### onFlutterSurfaceViewCreated

          public void onFlutterSurfaceViewCreated​(@NonNull
                                                  FlutterSurfaceView flutterSurfaceView)

    - #### onFlutterTextureViewCreated

          public void onFlutterTextureViewCreated​(@NonNull
                                                  FlutterTextureView flutterTextureView)

    - #### onFlutterUiDisplayed

          public void onFlutterUiDisplayed()

      Invoked after the `FlutterView` within this `FlutterFragment` starts rendering pixels to the screen.

      This method forwards `onFlutterUiDisplayed()` to its attached `Activity`, if the attached `Activity` implements `FlutterUiDisplayListener`.

      Subclasses that override this method must call through to the `super` method.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### onFlutterUiNoLongerDisplayed

          public void onFlutterUiNoLongerDisplayed()

      Invoked after the `FlutterView` within this `FlutterFragment` stops rendering pixels to the screen.

      This method forwards `onFlutterUiNoLongerDisplayed()` to its attached `Activity`, if the attached `Activity` implements `FlutterUiDisplayListener`.

      Subclasses that override this method must call through to the `super` method.

      Used by this `FlutterFragment`'s `FlutterActivityAndFragmentDelegate.Host`

    - #### shouldRestoreAndSaveState

          public boolean shouldRestoreAndSaveState()

    - #### updateSystemUiOverlays

          public void updateSystemUiOverlays()

    - #### shouldDispatchAppLifecycleState

          public boolean shouldDispatchAppLifecycleState()

      Give the host application a chance to take control of the app lifecycle events.

      Return `false` means the host application dispatches these app lifecycle events, while return `true` means the engine dispatches these events.

      Defaults to `true`.

    - #### popSystemNavigator

          public boolean popSystemNavigator()

      Allow implementer to customize the behavior needed when the Flutter framework calls to pop the Android-side navigation stack.

      Avoid overriding this method when using `shouldAutomaticallyHandleOnBackPressed(true)`. If you do, you must always `return super.popSystemNavigator()` rather than `return false`. Otherwise the navigation behavior will recurse infinitely between this method and `onBackPressed()`, breaking navigation.

      Specified by:
        `popSystemNavigator` in interface `PlatformPlugin.PlatformPluginDelegate`
      Returns:
        true if the implementation consumed the pop signal. If false, a default behavior of finishing the activity or sending the signal to `OnBackPressedDispatcher` will be executed.

    - #### getContext

          @NonNull
          public abstract Context getContext()

      Returns the `Context` that backs the host `Activity` or `Fragment`.

    - #### getActivity

          @Nullable
          public abstract Activity getActivity()

      Returns the host `Activity` or the `Activity` that is currently attached to the host `Fragment`.

    - #### getLifecycle

          @NonNull
          public abstract androidx.lifecycle.Lifecycle getLifecycle()

      Returns the `Lifecycle` that backs the host `Activity` or `Fragment`.