Fragment

<init>

Fragment()

Constructor used by the default FragmentFactory. You must set a custom FragmentFactory if you want to use a non-default constructor to ensure that your constructor is called when the fragment is re-instantiated.

It is strongly recommended to supply arguments with setArguments and later retrieved by the Fragment with getArguments. These arguments are automatically saved and restored alongside the Fragment.

Applications should generally not implement a constructor. Prefer onAttach(Context) instead. It is the first place application code can run where the fragment is ready to be used - the point where the fragment is actually associated with its context. Some applications may also want to implement onInflate to retrieve attributes from a layout resource, although note this happens when the fragment is attached.

<init>

Fragment(@LayoutRes contentLayoutId: Int)

Alternate constructor that can be called from your default, no argument constructor to provide a default layout that will be inflated by onCreateView(LayoutInflater, ViewGroup, Bundle).

class MyFragment extends Fragment {
        public MyFragment() {
          super(R.layout.fragment_main);
        }
      }
      

dump

open fun dump(
    @NonNull prefix: String, 
    @Nullable fd: FileDescriptor?, 
    @NonNull writer: PrintWriter, 
    @Nullable args: Array<String!>?
): Unit

Print the Fragments's state into the given stream.

equals

fun equals(@Nullable other: Any?): Boolean

Subclasses can not override equals().

getActivity

@Nullable fun getActivity(): FragmentActivity?

Return the FragmentActivity this fragment is currently associated with. May return null if the fragment is associated with a Context instead.

getAllowEnterTransitionOverlap

open fun getAllowEnterTransitionOverlap(): Boolean

Returns whether the the exit transition and enter transition overlap or not. When true, the enter transition will start as soon as possible. When false, the enter transition will wait until the exit transition completes before starting.

getAllowReturnTransitionOverlap

open fun getAllowReturnTransitionOverlap(): Boolean

Returns whether the the return transition and reenter transition overlap or not. When true, the reenter transition will start as soon as possible. When false, the reenter transition will wait until the return transition completes before starting.

getArguments

@Nullable fun getArguments(): Bundle?

Return the arguments supplied when the fragment was instantiated, if any.

getChildFragmentManager

@NonNull fun getChildFragmentManager(): FragmentManager

Return a private FragmentManager for placing and managing Fragments inside of this Fragment.

getContext

@Nullable open fun getContext(): Context?

Return the Context this fragment is currently associated with.

getDefaultViewModelProviderFactory

@NonNull open fun getDefaultViewModelProviderFactory(): ViewModelProvider.Factory

Returns the default ViewModelProvider.Factory that should be used when no custom Factory is provided to the ViewModelProvider constructors.

The Fragment's arguments when this is first called will be used as the defaults to any androidx.lifecycle.SavedStateHandle passed to a view model created using this factory.

getEnterTransition

@Nullable open fun getEnterTransition(): Any?

Returns the Transition that will be used to move Views into the initial scene. The entering Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as entering is governed by changing visibility from View#INVISIBLE to View#VISIBLE.

getExitTransition

@Nullable open fun getExitTransition(): Any?

Returns the Transition that will be used to move Views out of the scene when the fragment is removed, hidden, or detached when not popping the back stack. The exiting Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as exiting is governed by changing visibility from View#VISIBLE to View#INVISIBLE. If transition is null, the views will remain unaffected.

getFragmentManager

@Nullable fun getFragmentManager(): FragmentManager?

Deprecated: This has been removed in favor of getParentFragmentManager() which throws an IllegalStateException if the FragmentManager is null. Check if isAdded() returns false to determine if the FragmentManager is null.

Return the FragmentManager for interacting with fragments associated with this fragment's activity. Note that this will be non-null slightly before getActivity(), during the time from when the fragment is placed in a FragmentTransaction until it is committed and attached to its activity.

If this Fragment is a child of another Fragment, the FragmentManager returned here will be the parent's getChildFragmentManager().

getHost

@Nullable fun getHost(): Any?

Return the host object of this fragment. May return null if the fragment isn't currently being hosted.

getId

fun getId(): Int

Return the identifier this fragment is known by. This is either the android:id value supplied in a layout or the container view ID supplied when adding the fragment.

getLayoutInflater

@NonNull fun getLayoutInflater(): LayoutInflater

Returns the cached LayoutInflater used to inflate Views of this Fragment. If onGetLayoutInflater(Bundle) has not been called onGetLayoutInflater(Bundle) will be called with a null argument and that value will be cached.

The cached LayoutInflater will be replaced immediately prior to onCreateView(LayoutInflater, ViewGroup, Bundle) and cleared immediately after onDetach().

getLifecycle

@NonNull open fun getLifecycle(): Lifecycle

Returns the Lifecycle of the provider.

Overriding this method is no longer supported and this method will be made final in a future version of Fragment.

getLoaderManager

@NonNull open fun getLoaderManager(): LoaderManager

Deprecated: Use LoaderManager.getInstance(this).

Return the LoaderManager for this fragment.

getParentFragment

@Nullable fun getParentFragment(): Fragment?

Returns the parent Fragment containing this Fragment. If this Fragment is attached directly to an Activity, returns null.

getParentFragmentManager

@NonNull fun getParentFragmentManager(): FragmentManager

Return the FragmentManager for interacting with fragments associated with this fragment's activity. Note that this will available slightly before getActivity(), during the time from when the fragment is placed in a FragmentTransaction until it is committed and attached to its activity.

If this Fragment is a child of another Fragment, the FragmentManager returned here will be the parent's getChildFragmentManager().

getReenterTransition

@Nullable open fun getReenterTransition(): Any?

Returns the Transition that will be used to move Views in to the scene when returning due to popping a back stack. The entering Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as exiting is governed by changing visibility from View#VISIBLE to View#INVISIBLE. If nothing is set, the default will be to use the same transition as getExitTransition().

getResources

@NonNull fun getResources(): Resources

Return requireActivity().getResources().

getRetainInstance

fun getRetainInstance(): Boolean

Deprecated: Instead of retaining the Fragment itself, use a non-retained Fragment and keep retained state in a ViewModel attached to that Fragment. The ViewModel's constructor and its onCleared() callback provide the signal for initial creation and final destruction of the retained state.

Returns true if this fragment instance's state will be retained across configuration changes, and false if it will not.

getReturnTransition

@Nullable open fun getReturnTransition(): Any?

Returns the Transition that will be used to move Views out of the scene when the Fragment is preparing to be removed, hidden, or detached because of popping the back stack. The exiting Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as entering is governed by changing visibility from View#VISIBLE to View#INVISIBLE. If nothing is set, the default will be to use the same transition as getEnterTransition().

getSavedStateRegistry

@NonNull fun getSavedStateRegistry(): SavedStateRegistry

getSharedElementEnterTransition

@Nullable open fun getSharedElementEnterTransition(): Any?

Returns the Transition that will be used for shared elements transferred into the content Scene. Typical Transitions will affect size and location, such as android.transition.ChangeBounds. A null value will cause transferred shared elements to blink to the final position.

getSharedElementReturnTransition

@Nullable open fun getSharedElementReturnTransition(): Any?

Return the Transition that will be used for shared elements transferred back during a pop of the back stack. This Transition acts in the leaving Fragment. Typical Transitions will affect size and location, such as android.transition.ChangeBounds. A null value will cause transferred shared elements to blink to the final position. If no value is set, the default will be to use the same value as setSharedElementEnterTransition(Object).

getString

@NonNull fun getString(@StringRes resId: Int): String

Return a localized string from the application's package's default string table.

getString

@NonNull fun getString(
    @StringRes resId: Int, 
    @Nullable vararg formatArgs: Any!
): String

Return a localized formatted string from the application's package's default string table, substituting the format arguments as defined in java.util.Formatter and java.lang.String#format.

getTag

@Nullable fun getTag(): String?

Get the tag name of the fragment, if specified.

getTargetFragment

@Nullable fun getTargetFragment(): Fragment?

Deprecated: Instead of using a target fragment to pass results, use FragmentManager#setFragmentResult(String, Bundle) to deliver results to FragmentResultListener instances registered by other fragments via FragmentManager#setFragmentResultListener(String, LifecycleOwner, * FragmentResultListener).

Return the target fragment set by setTargetFragment.

getTargetRequestCode

fun getTargetRequestCode(): Int

Deprecated: When using the target fragment replacement of FragmentManager#setFragmentResultListener(String, LifecycleOwner, * FragmentResultListener) and FragmentManager#setFragmentResult(String, Bundle), consider using setArguments to pass a requestKey if you need to support dynamic request keys.

Return the target request code set by setTargetFragment.

getText

@NonNull fun getText(@StringRes resId: Int): CharSequence

Return a localized, styled CharSequence from the application's package's default string table.

getUserVisibleHint

open fun getUserVisibleHint(): Boolean

Deprecated: Use FragmentTransaction#setMaxLifecycle(Fragment, Lifecycle.State) instead.

getView

@Nullable open fun getView(): View?

Get the root view for the fragment's layout (the one returned by onCreateView), if provided.

getViewLifecycleOwner

@MainThread @NonNull open fun getViewLifecycleOwner(): LifecycleOwner

Get a LifecycleOwner that represents the Fragment's View lifecycle. In most cases, this mirrors the lifecycle of the Fragment itself, but in cases of detached Fragments, the lifecycle of the Fragment can be considerably longer than the lifecycle of the View itself.

Namely, the lifecycle of the Fragment's View is:

1. created after onViewStateRestored(Bundle)
2. started after onStart()
3. resumed after onResume()
4. paused before onPause()
5. stopped before onStop()
6. destroyed before onDestroyView()

The view lifecycle remains valid through the call to onDestroyView(), after which getView() will return null, the view lifecycle will be destroyed, and this method will throw an IllegalStateException. Consider using getViewLifecycleOwnerLiveData() or FragmentTransaction#runOnCommit(Runnable) to receive a callback for when the Fragment's view lifecycle is available.

This should only be called on the main thread.

Overriding this method is no longer supported and this method will be made final in a future version of Fragment.

getViewLifecycleOwnerLiveData

@NonNull open fun getViewLifecycleOwnerLiveData(): LiveData<LifecycleOwner!>

Retrieve a LiveData which allows you to observe the lifecycle of the Fragment's View.

This will be set to the new LifecycleOwner after onCreateView returns a non-null View and will set to null after onDestroyView().

Overriding this method is no longer supported and this method will be made final in a future version of Fragment.

getViewModelStore

@NonNull open fun getViewModelStore(): ViewModelStore

Returns the ViewModelStore associated with this Fragment

Overriding this method is no longer supported and this method will be made final in a future version of Fragment.

hashCode

fun hashCode(): Int

Subclasses can not override hashCode().

instantiate

@NonNull open static fun instantiate(
    @NonNull context: Context, 
    @NonNull fname: String
): Fragment

Deprecated: Use FragmentManager#getFragmentFactory() and FragmentFactory#instantiate(ClassLoader, String)

Like instantiate(Context, String, Bundle) but with a null argument Bundle.

instantiate

@NonNull open static fun instantiate(
    @NonNull context: Context, 
    @NonNull fname: String, 
    @Nullable args: Bundle?
): Fragment

Deprecated: Use FragmentManager#getFragmentFactory() and FragmentFactory#instantiate(ClassLoader, String), manually calling setArguments(Bundle) on the returned Fragment.

Create a new instance of a Fragment with the given class name. This is the same as calling its empty constructor, setting the ClassLoader on the supplied arguments, then calling setArguments(Bundle).

isAdded

fun isAdded(): Boolean

Return true if the fragment is currently added to its activity.

isDetached

fun isDetached(): Boolean

Return true if the fragment has been explicitly detached from the UI. That is, FragmentTransaction.detach(Fragment) has been used on it.

isHidden

fun isHidden(): Boolean

Return true if the fragment has been hidden. By default fragments are shown. You can find out about changes to this state with onHiddenChanged. Note that the hidden state is orthogonal to other states -- that is, to be visible to the user, a fragment must be both started and not hidden.

isInLayout

fun isInLayout(): Boolean

Return true if the layout is included as part of an activity view hierarchy via the <fragment> tag. This will always be true when fragments are created through the <fragment> tag, except in the case where an old fragment is restored from a previous state and it does not appear in the layout of the current state.

isRemoving

fun isRemoving(): Boolean

Return true if this fragment is currently being removed from its activity. This is not whether its activity is finishing, but rather whether it is in the process of being removed from its activity.

isResumed

fun isResumed(): Boolean

Return true if the fragment is in the resumed state. This is true for the duration of onResume() and onPause() as well.

isStateSaved

fun isStateSaved(): Boolean

Returns true if this fragment is added and its state has already been saved by its host. Any operations that would change saved state should not be performed if this method returns true, and some operations such as setArguments(Bundle) will fail.

isVisible

fun isVisible(): Boolean

Return true if the fragment is currently visible to the user. This means it: (1) has been added, (2) has its view attached to the window, and (3) is not hidden.

onActivityCreated

@MainThread @CallSuper open fun onActivityCreated(@Nullable savedInstanceState: Bundle?): Unit

Deprecated: use onViewCreated(View, Bundle) for code touching the Fragment's view and onCreate(Bundle) for other initialization. To get a callback specifically when a Fragment activity's Activity#onCreate(Bundle) is called, register a androidx.lifecycle.LifecycleObserver on the Activity's Lifecycle in onAttach(Context), removing it when it receives the Lifecycle.State#CREATED callback.

Called when the fragment's activity has been created and this fragment's view hierarchy instantiated. It can be used to do final initialization once these pieces are in place, such as retrieving views or restoring state. It is also useful for fragments that use setRetainInstance(boolean) to retain their instance, as this callback tells the fragment when it is fully associated with the new activity instance. This is called after onCreateView and before onViewStateRestored(Bundle).

onActivityResult

open fun onActivityResult(
    requestCode: Int, 
    resultCode: Int, 
    @Nullable data: Intent?
): Unit

Deprecated: use registerForActivityResult(ActivityResultContract, ActivityResultCallback) with the appropriate ActivityResultContract and handling the result in the callback.

Receive the result from a previous call to startActivityForResult(Intent, int). This follows the related Activity API as described there in Activity#onActivityResult(int, int, Intent).

onAttach

@MainThread @CallSuper open fun onAttach(@NonNull context: Context): Unit

Called when a fragment is first attached to its context. onCreate(Bundle) will be called after this.

onAttach

@MainThread @CallSuper open fun onAttach(@NonNull activity: Activity): Unit

Deprecated: See onAttach(Context).

Called when a fragment is first attached to its activity. onCreate(Bundle) will be called after this.

onAttachFragment

@MainThread open fun onAttachFragment(@NonNull childFragment: Fragment): Unit

Called when a fragment is attached as a child of this fragment.

This is called after the attached fragment's onAttach and before the attached fragment's onCreate if the fragment has not yet had a previous call to onCreate.

onConfigurationChanged

@CallSuper open fun onConfigurationChanged(@NonNull newConfig: Configuration): Unit

onContextItemSelected

@MainThread open fun onContextItemSelected(@NonNull item: MenuItem): Boolean

This hook is called whenever an item in a context menu is selected. The default implementation simply returns false to have the normal processing happen (calling the item's Runnable or sending a message to its Handler as appropriate). You can use this method for any items for which you would like to do processing without those other facilities.

Use MenuItem#getMenuInfo() to get extra information set by the View that added this menu item.

Derived classes should call through to the base class for it to perform the default menu handling.

onCreate

@MainThread @CallSuper open fun onCreate(@Nullable savedInstanceState: Bundle?): Unit

Called to do initial creation of a fragment. This is called after onAttach(Activity) and before onCreateView(LayoutInflater, ViewGroup, Bundle).

Note that this can be called while the fragment's activity is still in the process of being created. As such, you can not rely on things like the activity's content view hierarchy being initialized at this point. If you want to do work once the activity itself is created, add a androidx.lifecycle.LifecycleObserver on the activity's Lifecycle, removing it when it receives the Lifecycle.State#CREATED callback.

Any restored child fragments will be created before the base Fragment.onCreate method returns.

onCreateAnimation

@MainThread @Nullable open fun onCreateAnimation(
    transit: Int, 
    enter: Boolean, 
    nextAnim: Int
): Animation?

Called when a fragment loads an animation. Note that if FragmentTransaction#setCustomAnimations(int, int) was called with Animator resources instead of Animation resources, nextAnim will be an animator resource.

onCreateAnimator

@MainThread @Nullable open fun onCreateAnimator(
    transit: Int, 
    enter: Boolean, 
    nextAnim: Int
): Animator?

Called when a fragment loads an animator. This will be called when onCreateAnimation(int, boolean, int) returns null. Note that if FragmentTransaction#setCustomAnimations(int, int) was called with Animation resources instead of Animator resources, nextAnim will be an animation resource.

onCreateContextMenu

@MainThread open fun onCreateContextMenu(
    @NonNull menu: ContextMenu, 
    @NonNull v: View, 
    @Nullable menuInfo: ContextMenuInfo?
): Unit

Called when a context menu for the view is about to be shown. Unlike onCreateOptionsMenu, this will be called every time the context menu is about to be shown and should be populated for the view (or item inside the view for AdapterView subclasses, this can be found in the menuInfo)).

Use onContextItemSelected(android.view.MenuItem) to know when an item has been selected.

The default implementation calls up to Activity.onCreateContextMenu, though you can not call this implementation if you don't want that behavior.

It is not safe to hold onto the context menu after this method returns.

onCreateOptionsMenu

@MainThread open fun onCreateOptionsMenu(
    @NonNull menu: Menu, 
    @NonNull inflater: MenuInflater
): Unit

Initialize the contents of the Fragment host's standard options menu. You should place your menu items in to menu. For this method to be called, you must have first called setHasOptionsMenu. See Activity.onCreateOptionsMenu for more information.

onCreateView

@MainThread @Nullable open fun onCreateView(
    @NonNull inflater: LayoutInflater, 
    @Nullable container: ViewGroup?, 
    @Nullable savedInstanceState: Bundle?
): View?

Called to have the fragment instantiate its user interface view. This is optional, and non-graphical fragments can return null. This will be called between onCreate(Bundle) and onViewCreated(View, Bundle).

A default View can be returned by calling Fragment(int) in your constructor. Otherwise, this method returns null.

It is recommended to only inflate the layout in this method and move logic that operates on the returned View to onViewCreated(View, Bundle).

If you return a View from here, you will later be called in onDestroyView when the view is being released.

onDestroy

@MainThread @CallSuper open fun onDestroy(): Unit

Called when the fragment is no longer in use. This is called after onStop() and before onDetach().

onDestroyOptionsMenu

@MainThread open fun onDestroyOptionsMenu(): Unit

Called when this fragment's option menu items are no longer being included in the overall options menu. Receiving this call means that the menu needed to be rebuilt, but this fragment's items were not included in the newly built menu (its onCreateOptionsMenu(Menu, MenuInflater) was not called).

onDestroyView

@MainThread @CallSuper open fun onDestroyView(): Unit

Called when the view previously created by onCreateView has been detached from the fragment. The next time the fragment needs to be displayed, a new view will be created. This is called after onStop() and before onDestroy(). It is called regardless of whether onCreateView returned a non-null view. Internally it is called after the view's state has been saved but before it has been removed from its parent.

onDetach

@MainThread @CallSuper open fun onDetach(): Unit

Called when the fragment is no longer attached to its activity. This is called after onDestroy().

onGetLayoutInflater

@NonNull open fun onGetLayoutInflater(@Nullable savedInstanceState: Bundle?): LayoutInflater

Returns the LayoutInflater used to inflate Views of this Fragment. The default implementation will throw an exception if the Fragment is not attached.

onHiddenChanged

@MainThread open fun onHiddenChanged(hidden: Boolean): Unit

Called when the hidden state (as returned by isHidden() of the fragment has changed. Fragments start out not hidden; this will be called whenever the fragment changes state from that.

onInflate

@UiThread @CallSuper open fun onInflate(
    @NonNull context: Context, 
    @NonNull attrs: AttributeSet, 
    @Nullable savedInstanceState: Bundle?
): Unit

Called when a fragment is being created as part of a view layout inflation, typically from setting the content view of an activity. This may be called immediately after the fragment is created from a FragmentContainerView in a layout file. Note this is before the fragment's onAttach(Context) has been called; all you should do here is parse the attributes and save them away.

This is called the first time the fragment is inflated. If it is being inflated into a new instance with saved state, this method will not be called a second time for the restored state fragment.

Here is a typical implementation of a fragment that can take parameters both through attributes supplied here as well from getArguments():

Note that parsing the XML attributes uses a "styleable" resource. The declaration for the styleable used here is:

The fragment can then be declared within its activity's content layout through a tag like this:

This fragment can also be created dynamically from arguments given at runtime in the arguments Bundle; here is an example of doing so at creation of the containing activity:

onInflate

@UiThread @CallSuper open fun onInflate(
    @NonNull activity: Activity, 
    @NonNull attrs: AttributeSet, 
    @Nullable savedInstanceState: Bundle?
): Unit

Deprecated: See onInflate(Context, AttributeSet, Bundle).

Called when a fragment is being created as part of a view layout inflation, typically from setting the content view of an activity.

onLowMemory

@MainThread @CallSuper open fun onLowMemory(): Unit

onMultiWindowModeChanged

open fun onMultiWindowModeChanged(isInMultiWindowMode: Boolean): Unit

Called when the Fragment's activity changes from fullscreen mode to multi-window mode and visa-versa. This is generally tied to Activity#onMultiWindowModeChanged of the containing Activity.

onOptionsItemSelected

@MainThread open fun onOptionsItemSelected(@NonNull item: MenuItem): Boolean

This hook is called whenever an item in your options menu is selected. The default implementation simply returns false to have the normal processing happen (calling the item's Runnable or sending a message to its Handler as appropriate). You can use this method for any items for which you would like to do processing without those other facilities.

Derived classes should call through to the base class for it to perform the default menu handling.

onOptionsMenuClosed

@MainThread open fun onOptionsMenuClosed(@NonNull menu: Menu): Unit

This hook is called whenever the options menu is being closed (either by the user canceling the menu with the back/menu button, or when an item is selected).

onPause

@MainThread @CallSuper open fun onPause(): Unit

Called when the Fragment is no longer resumed. This is generally tied to Activity.onPause of the containing Activity's lifecycle.

onPictureInPictureModeChanged

open fun onPictureInPictureModeChanged(isInPictureInPictureMode: Boolean): Unit

Called by the system when the activity changes to and from picture-in-picture mode. This is generally tied to Activity#onPictureInPictureModeChanged of the containing Activity.

onPrepareOptionsMenu

@MainThread open fun onPrepareOptionsMenu(@NonNull menu: Menu): Unit

Prepare the Fragment host's standard options menu to be displayed. This is called right before the menu is shown, every time it is shown. You can use this method to efficiently enable/disable items or otherwise dynamically modify the contents. See Activity.onPrepareOptionsMenu for more information.

onPrimaryNavigationFragmentChanged

@MainThread open fun onPrimaryNavigationFragmentChanged(isPrimaryNavigationFragment: Boolean): Unit

Callback for when the primary navigation state of this Fragment has changed. This can be the result of the getParentFragmentManager() containing FragmentManager} having its primary navigation fragment changed via androidx.fragment.app.FragmentTransaction#setPrimaryNavigationFragment or due to the primary navigation fragment changing in a parent FragmentManager.

onRequestPermissionsResult

open fun onRequestPermissionsResult(
    requestCode: Int, 
    @NonNull permissions: Array<String!>, 
    @NonNull grantResults: IntArray
): Unit

Deprecated: use registerForActivityResult(ActivityResultContract, ActivityResultCallback) passing in a RequestMultiplePermissions object for the ActivityResultContract and handling the result in the callback.

Callback for the result from requesting permissions. This method is invoked for every call on requestPermissions(String[], int).

Note: It is possible that the permissions request interaction with the user is interrupted. In this case you will receive empty permissions and results arrays which should be treated as a cancellation.

onResume

@MainThread @CallSuper open fun onResume(): Unit

Called when the fragment is visible to the user and actively running. This is generally tied to Activity.onResume of the containing Activity's lifecycle.

onSaveInstanceState

@MainThread open fun onSaveInstanceState(@NonNull outState: Bundle): Unit

Called to ask the fragment to save its current dynamic state, so it can later be reconstructed in a new instance if its process is restarted. If a new instance of the fragment later needs to be created, the data you place in the Bundle here will be available in the Bundle given to onCreate(Bundle), onCreateView(LayoutInflater, ViewGroup, Bundle), and onViewCreated(View, Bundle).

This corresponds to Activity.onSaveInstanceState(Bundle) and most of the discussion there applies here as well. Note however: this method may be called at any time before onDestroy(). There are many situations where a fragment may be mostly torn down (such as when placed on the back stack with no UI showing), but its state will not be saved until its owning activity actually needs to save its state.

onStart

@MainThread @CallSuper open fun onStart(): Unit

Called when the Fragment is visible to the user. This is generally tied to Activity.onStart of the containing Activity's lifecycle.

onStop

@MainThread @CallSuper open fun onStop(): Unit

Called when the Fragment is no longer started. This is generally tied to Activity.onStop of the containing Activity's lifecycle.

onViewCreated

@MainThread open fun onViewCreated(
    @NonNull view: View, 
    @Nullable savedInstanceState: Bundle?
): Unit

Called immediately after onCreateView(LayoutInflater, ViewGroup, Bundle) has returned, but before any saved state has been restored in to the view. This gives subclasses a chance to initialize themselves once they know their view hierarchy has been completely created. The fragment's view hierarchy is not however attached to its parent at this point.

onViewStateRestored

@MainThread @CallSuper open fun onViewStateRestored(@Nullable savedInstanceState: Bundle?): Unit

Called when all saved state has been restored into the view hierarchy of the fragment. This can be used to do initialization based on saved state that you are letting the view hierarchy track itself, such as whether check box widgets are currently checked. This is called after onViewCreated(View, Bundle) and before onStart().

postponeEnterTransition

open fun postponeEnterTransition(): Unit

Postpone the entering Fragment transition until startPostponedEnterTransition() or FragmentManager#executePendingTransactions() has been called.

This method gives the Fragment the ability to delay Fragment animations until all data is loaded. Until then, the added, shown, and attached Fragments will be INVISIBLE and removed, hidden, and detached Fragments won't be have their Views removed. The transaction runs when all postponed added Fragments in the transaction have called startPostponedEnterTransition().

This method should be called before being added to the FragmentTransaction or in onCreate(Bundle), onAttach(Context), or onCreateView(LayoutInflater, ViewGroup, Bundle)}. startPostponedEnterTransition() must be called to allow the Fragment to start the transitions.

When a FragmentTransaction is started that may affect a postponed FragmentTransaction, based on which containers are in their operations, the postponed FragmentTransaction will have its start triggered. The early triggering may result in faulty or nonexistent animations in the postponed transaction. FragmentTransactions that operate only on independent containers will not interfere with each other's postponement.

Calling postponeEnterTransition on Fragments with a null View will not postpone the transition. Likewise, postponement only works if FragmentTransaction reordering is enabled.

postponeEnterTransition

fun postponeEnterTransition(
    duration: Long, 
    @NonNull timeUnit: TimeUnit
): Unit

Postpone the entering Fragment transition for a given amount of time and then call startPostponedEnterTransition().

This method gives the Fragment the ability to delay Fragment animations for a given amount of time. Until then, the added, shown, and attached Fragments will be INVISIBLE and removed, hidden, and detached Fragments won't be have their Views removed. The transaction runs when all postponed added Fragments in the transaction have called startPostponedEnterTransition().

This method should be called before being added to the FragmentTransaction or in onCreate(Bundle), onAttach(Context), or onCreateView(LayoutInflater, ViewGroup, Bundle)}.

When a FragmentTransaction is started that may affect a postponed FragmentTransaction, based on which containers are in their operations, the postponed FragmentTransaction will have its start triggered. The early triggering may result in faulty or nonexistent animations in the postponed transaction. FragmentTransactions that operate only on independent containers will not interfere with each other's postponement.

Calling postponeEnterTransition on Fragments with a null View will not postpone the transition. Likewise, postponement only works if FragmentTransaction reordering is enabled.

registerForActivityResult

@NonNull fun <I : Any!, O : Any!> registerForActivityResult(
    @NonNull contract: ActivityResultContract<I, O>, 
    @NonNull callback: ActivityResultCallback<O>
): ActivityResultLauncher<I>

Register a request to start an activity for result, designated by the given contract. This creates a record in the registry associated wit this caller, managing request code, as well as conversions to/from Intent under the hood. This *must* be called unconditionally, as part of initialization path, typically as a field initializer of an Activity or Fragment.

If the host of this fragment is an ActivityResultRegistryOwner the ActivityResultRegistry of the host will be used. Otherwise, this will use the registry of the Fragment's Activity.

registerForActivityResult

@NonNull fun <I : Any!, O : Any!> registerForActivityResult(
    @NonNull contract: ActivityResultContract<I, O>, 
    @NonNull registry: ActivityResultRegistry, 
    @NonNull callback: ActivityResultCallback<O>
): ActivityResultLauncher<I>

registerForContextMenu

open fun registerForContextMenu(@NonNull view: View): Unit

Registers a context menu to be shown for the given view (multiple views can show the context menu). This method will set the OnCreateContextMenuListener on the view to this fragment, so onCreateContextMenu(ContextMenu, View, ContextMenuInfo) will be called when it is time to show the context menu.

requestPermissions

fun requestPermissions(
    @NonNull permissions: Array<String!>, 
    requestCode: Int
): Unit

Deprecated: use registerForActivityResult(ActivityResultContract, ActivityResultCallback) passing in a RequestMultiplePermissions object for the ActivityResultContract and handling the result in the callback.

Requests permissions to be granted to this application. These permissions must be requested in your manifest, they should not be granted to your app, and they should have protection level #PROTECTION_DANGEROUS dangerous, regardless whether they are declared by the platform or a third-party app.

Normal permissions android.content.pm.PermissionInfo#PROTECTION_NORMAL are granted at install time if requested in the manifest. Signature permissions android.content.pm.PermissionInfo#PROTECTION_SIGNATURE are granted at install time if requested in the manifest and the signature of your app matches the signature of the app declaring the permissions.

If your app does not have the requested permissions the user will be presented with UI for accepting them. After the user has accepted or rejected the requested permissions you will receive a callback on reporting whether the permissions were granted or not.

Note that requesting a permission does not guarantee it will be granted and your app should be able to run without having this permission.

This method may start an activity allowing the user to choose which permissions to grant and which to reject. Hence, you should be prepared that your activity may be paused and resumed. Further, granting some permissions may require a restart of you application. In such a case, the system will recreate the activity stack before delivering the result to .

When checking whether you have a permission you should use .

Calling this API for permissions already granted to your app would show UI to the user to decided whether the app can still hold these permissions. This can be useful if the way your app uses the data guarded by the permissions changes significantly.

A sample permissions request looks like this:

<code><p> private void showContacts() { if (getActivity().checkSelfPermission(Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) { requestPermissions(new String[]{Manifest.permission.READ_CONTACTS}, PERMISSIONS_REQUEST_READ_CONTACTS); } else { doShowContacts(); } } @Override public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { if (requestCode == PERMISSIONS_REQUEST_READ_CONTACTS &amp;&amp; grantResults[0] == PackageManager.PERMISSION_GRANTED) { doShowContacts(); } } </p></code>

requireActivity

@NonNull fun requireActivity(): FragmentActivity

Return the FragmentActivity this fragment is currently associated with.

requireArguments

@NonNull fun requireArguments(): Bundle

Return the arguments supplied when the fragment was instantiated.

requireContext

@NonNull fun requireContext(): Context

Return the Context this fragment is currently associated with.

requireFragmentManager

@NonNull fun requireFragmentManager(): FragmentManager

Deprecated: This has been renamed to getParentFragmentManager() to make it clear that you are accessing the FragmentManager that contains this Fragment and not the FragmentManager associated with child Fragments.

Return the FragmentManager for interacting with fragments associated with this fragment's activity. Note that this will available slightly before getActivity(), during the time from when the fragment is placed in a FragmentTransaction until it is committed and attached to its activity.

If this Fragment is a child of another Fragment, the FragmentManager returned here will be the parent's getChildFragmentManager().

requireHost

@NonNull fun requireHost(): Any

Return the host object of this fragment.

requireParentFragment

@NonNull fun requireParentFragment(): Fragment

Returns the parent Fragment containing this Fragment.

requireView

@NonNull fun requireView(): View

Get the root view for the fragment's layout (the one returned by onCreateView).

setAllowEnterTransitionOverlap

open fun setAllowEnterTransitionOverlap(allow: Boolean): Unit

Sets whether the the exit transition and enter transition overlap or not. When true, the enter transition will start as soon as possible. When false, the enter transition will wait until the exit transition completes before starting.

setAllowReturnTransitionOverlap

open fun setAllowReturnTransitionOverlap(allow: Boolean): Unit

Sets whether the the return transition and reenter transition overlap or not. When true, the reenter transition will start as soon as possible. When false, the reenter transition will wait until the return transition completes before starting.

setArguments

open fun setArguments(@Nullable args: Bundle?): Unit

Supply the construction arguments for this fragment. The arguments supplied here will be retained across fragment destroy and creation.

This method cannot be called if the fragment is added to a FragmentManager and if isStateSaved() would return true.

setEnterSharedElementCallback

open fun setEnterSharedElementCallback(@Nullable callback: SharedElementCallback?): Unit

When custom transitions are used with Fragments, the enter transition callback is called when this Fragment is attached or detached when not popping the back stack.

setEnterTransition

open fun setEnterTransition(@Nullable transition: Any?): Unit

Sets the Transition that will be used to move Views into the initial scene. The entering Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as entering is governed by changing visibility from View#INVISIBLE to View#VISIBLE. If transition is null, entering Views will remain unaffected.

setExitSharedElementCallback

open fun setExitSharedElementCallback(@Nullable callback: SharedElementCallback?): Unit

When custom transitions are used with Fragments, the exit transition callback is called when this Fragment is attached or detached when popping the back stack.

setExitTransition

open fun setExitTransition(@Nullable transition: Any?): Unit

Sets the Transition that will be used to move Views out of the scene when the fragment is removed, hidden, or detached when not popping the back stack. The exiting Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as exiting is governed by changing visibility from View#VISIBLE to View#INVISIBLE. If transition is null, the views will remain unaffected.

setHasOptionsMenu

open fun setHasOptionsMenu(hasMenu: Boolean): Unit

Report that this fragment would like to participate in populating the options menu by receiving a call to onCreateOptionsMenu and related methods.

setInitialSavedState

open fun setInitialSavedState(@Nullable state: Fragment.SavedState?): Unit

Set the initial saved state that this Fragment should restore itself from when first being constructed, as returned by FragmentManager.saveFragmentInstanceState.

setMenuVisibility

open fun setMenuVisibility(menuVisible: Boolean): Unit

Set a hint for whether this fragment's menu should be visible. This is useful if you know that a fragment has been placed in your view hierarchy so that the user can not currently seen it, so any menu items it has should also not be shown.

setReenterTransition

open fun setReenterTransition(@Nullable transition: Any?): Unit

Sets the Transition that will be used to move Views in to the scene when returning due to popping a back stack. The entering Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as exiting is governed by changing visibility from View#VISIBLE to View#INVISIBLE. If transition is null, the views will remain unaffected. If nothing is set, the default will be to use the same transition as getExitTransition().

setRetainInstance

open fun setRetainInstance(retain: Boolean): Unit

Deprecated: Instead of retaining the Fragment itself, use a non-retained Fragment and keep retained state in a ViewModel attached to that Fragment. The ViewModel's constructor and its onCleared() callback provide the signal for initial creation and final destruction of the retained state.

Control whether a fragment instance is retained across Activity re-creation (such as from a configuration change). If set, the fragment lifecycle will be slightly different when an activity is recreated:

• onDestroy() will not be called (but onDetach() still will be, because the fragment is being detached from its current activity).
• onCreate(Bundle) will not be called since the fragment is not being re-created.
• onAttach(Activity) and onActivityCreated(Bundle) will still be called.

setReturnTransition

open fun setReturnTransition(@Nullable transition: Any?): Unit

Sets the Transition that will be used to move Views out of the scene when the Fragment is preparing to be removed, hidden, or detached because of popping the back stack. The exiting Views will be those that are regular Views or ViewGroups that have ViewGroup#isTransitionGroup return true. Typical Transitions will extend android.transition.Visibility as entering is governed by changing visibility from View#VISIBLE to View#INVISIBLE. If transition is null, entering Views will remain unaffected. If nothing is set, the default will be to use the same value as set in setEnterTransition(Object).

setSharedElementEnterTransition

open fun setSharedElementEnterTransition(@Nullable transition: Any?): Unit

Sets the Transition that will be used for shared elements transferred into the content Scene. Typical Transitions will affect size and location, such as android.transition.ChangeBounds. A null value will cause transferred shared elements to blink to the final position.

setSharedElementReturnTransition

open fun setSharedElementReturnTransition(@Nullable transition: Any?): Unit

Sets the Transition that will be used for shared elements transferred back during a pop of the back stack. This Transition acts in the leaving Fragment. Typical Transitions will affect size and location, such as android.transition.ChangeBounds. A null value will cause transferred shared elements to blink to the final position. If no value is set, the default will be to use the same value as setSharedElementEnterTransition(Object).

setTargetFragment

open fun setTargetFragment(
    @Nullable fragment: Fragment?, 
    requestCode: Int
): Unit

Deprecated: Instead of using a target fragment to pass results, the fragment requesting a result should use FragmentManager#setFragmentResultListener(String, LifecycleOwner, * FragmentResultListener) to register a FragmentResultListener with a requestKey using its parent fragment manager. The fragment delivering a result should then call FragmentManager#setFragmentResult(String, Bundle) using the same requestKey. Consider using setArguments to pass the requestKey if you need to support dynamic request keys.

Optional target for this fragment. This may be used, for example, if this fragment is being started by another, and when done wants to give a result back to the first. The target set here is retained across instances via FragmentManager.putFragment().

setUserVisibleHint

open fun setUserVisibleHint(isVisibleToUser: Boolean): Unit

Deprecated: If you are manually calling this method, use FragmentTransaction#setMaxLifecycle(Fragment, Lifecycle.State) instead. If overriding this method, behavior implemented when passing in true should be moved to Fragment#onResume(), and behavior implemented when passing in false should be moved to Fragment#onPause().

Set a hint to the system about whether this fragment's UI is currently visible to the user. This hint defaults to true and is persistent across fragment instance state save and restore.

An app may set this to false to indicate that the fragment's UI is scrolled out of visibility or is otherwise not directly visible to the user. This may be used by the system to prioritize operations such as fragment lifecycle updates or loader ordering behavior.

Note: This method may be called outside of the fragment lifecycle. and thus has no ordering guarantees with regard to fragment lifecycle method calls.

shouldShowRequestPermissionRationale

open fun shouldShowRequestPermissionRationale(@NonNull permission: String): Boolean

Gets whether you should show UI with rationale for requesting a permission. You should do this only if you do not have the permission and the context in which the permission is requested does not clearly communicate to the user what would be the benefit from granting this permission.

For example, if you write a camera app, requesting the camera permission would be expected by the user and no rationale for why it is requested is needed. If however, the app needs location for tagging photos then a non-tech savvy user may wonder how location is related to taking photos. In this case you may choose to show UI with rationale of requesting this permission.

startActivity

open fun startActivity(intent: Intent!): Unit

Call Activity#startActivity(Intent) from the fragment's containing Activity.

startActivity

open fun startActivity(
    intent: Intent!, 
    @Nullable options: Bundle?
): Unit

Call Activity#startActivity(Intent, Bundle) from the fragment's containing Activity.

startActivityForResult

open fun startActivityForResult(
    intent: Intent!, 
    requestCode: Int
): Unit

Deprecated: use registerForActivityResult(ActivityResultContract, ActivityResultCallback) passing in a StartActivityForResult object for the ActivityResultContract.

Call Activity#startActivityForResult(Intent, int) from the fragment's containing Activity.

startActivityForResult

open fun startActivityForResult(
    intent: Intent!, 
    requestCode: Int, 
    @Nullable options: Bundle?
): Unit

Deprecated: use registerForActivityResult(ActivityResultContract, ActivityResultCallback) passing in a StartActivityForResult object for the ActivityResultContract.

Call Activity#startActivityForResult(Intent, int, Bundle) from the fragment's containing Activity.

startIntentSenderForResult

open fun startIntentSenderForResult(
    intent: IntentSender!, 
    requestCode: Int, 
    @Nullable fillInIntent: Intent?, 
    flagsMask: Int, 
    flagsValues: Int, 
    extraFlags: Int, 
    @Nullable options: Bundle?
): Unit

Deprecated: use registerForActivityResult(ActivityResultContract, ActivityResultCallback) passing in a StartIntentSenderForResult object for the ActivityResultContract.

Call Activity#startIntentSenderForResult(IntentSender, int, Intent, int, int, int, * Bundle) from the fragment's containing Activity.

startPostponedEnterTransition

open fun startPostponedEnterTransition(): Unit

Begin postponed transitions after postponeEnterTransition() was called. If postponeEnterTransition() was called, you must call startPostponedEnterTransition() or FragmentManager#executePendingTransactions() to complete the FragmentTransaction. If postponement was interrupted with FragmentManager#executePendingTransactions(), before startPostponedEnterTransition(), animations may not run or may execute improperly.

toString