FragmentController.java
/*
* Copyright 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.fragment.app;
import static androidx.core.util.Preconditions.checkNotNull;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.content.res.Configuration;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.collection.SimpleArrayMap;
import androidx.lifecycle.ViewModelStoreOwner;
import androidx.loader.app.LoaderManager;
import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
/**
* Provides integration points with a {@link FragmentManager} for a fragment host.
* <p>
* It is the responsibility of the host to take care of the Fragment's lifecycle.
* The methods provided by {@link FragmentController} are for that purpose.
*/
public class FragmentController {
private final FragmentHostCallback<?> mHost;
/**
* Returns a {@link FragmentController}.
*/
@NonNull
public static FragmentController createController(@NonNull FragmentHostCallback<?> callbacks) {
return new FragmentController(checkNotNull(callbacks, "callbacks == null"));
}
private FragmentController(FragmentHostCallback<?> callbacks) {
mHost = callbacks;
}
/**
* Returns a {@link FragmentManager} for this controller.
*/
@NonNull
public FragmentManager getSupportFragmentManager() {
return mHost.mFragmentManager;
}
/**
* Returns a {@link LoaderManager}.
*
* @deprecated Loaders are managed separately from FragmentController and this now throws an
* {@link UnsupportedOperationException}. Use {@link LoaderManager#getInstance} to obtain a
* LoaderManager.
* @see LoaderManager#getInstance
*/
@Deprecated
@SuppressLint("UnknownNullness")
public LoaderManager getSupportLoaderManager() {
throw new UnsupportedOperationException("Loaders are managed separately from "
+ "FragmentController, use LoaderManager.getInstance() to obtain a LoaderManager.");
}
/**
* Returns a fragment with the given identifier.
*/
@Nullable
public Fragment findFragmentByWho(@NonNull String who) {
return mHost.mFragmentManager.findFragmentByWho(who);
}
/**
* Returns the number of active fragments.
*/
public int getActiveFragmentsCount() {
return mHost.mFragmentManager.getActiveFragmentCount();
}
/**
* Returns the list of active fragments.
*/
@NonNull
public List<Fragment> getActiveFragments(@SuppressLint("UnknownNullness")
List<Fragment> actives) {
return mHost.mFragmentManager.getActiveFragments();
}
/**
* Attaches the host to the FragmentManager for this controller. The host must be
* attached before the FragmentManager can be used to manage Fragments.
*/
public void attachHost(@Nullable Fragment parent) {
mHost.mFragmentManager.attachController(
mHost, mHost /*container*/, parent);
}
/**
* Instantiates a Fragment's view.
*
* @param parent The parent that the created view will be placed
* in; <em>note that this may be null</em>.
* @param name Tag name to be inflated.
* @param context The context the view is being created in.
* @param attrs Inflation attributes as specified in XML file.
*
* @return view the newly created view
*/
@Nullable
public View onCreateView(@Nullable View parent, @NonNull String name, @NonNull Context context,
@NonNull AttributeSet attrs) {
return mHost.mFragmentManager.getLayoutInflaterFactory()
.onCreateView(parent, name, context, attrs);
}
/**
* Marks the fragment state as unsaved. This allows for "state loss" detection.
*/
public void noteStateNotSaved() {
mHost.mFragmentManager.noteStateNotSaved();
}
/**
* Saves the state for all Fragments.
*
* @see #restoreSaveState(Parcelable)
*/
@Nullable
public Parcelable saveAllState() {
return mHost.mFragmentManager.saveAllState();
}
/**
* Restores the saved state for all Fragments. The given Fragment list are Fragment
* instances retained across configuration changes.
*
* @deprecated Have your {@link FragmentHostCallback} implement {@link ViewModelStoreOwner}
* to automatically restore the Fragment's non configuration state and use
* {@link #restoreSaveState(Parcelable)} to restore the Fragment's save state.
*/
@SuppressWarnings("deprecation")
@Deprecated
public void restoreAllState(@Nullable Parcelable state,
@Nullable List<Fragment> nonConfigList) {
mHost.mFragmentManager.restoreAllState(state,
new FragmentManagerNonConfig(nonConfigList, null, null));
}
/**
* Restores the saved state for all Fragments. The given FragmentManagerNonConfig are Fragment
* instances retained across configuration changes, including nested fragments
*
* @deprecated Have your {@link FragmentHostCallback} implement {@link ViewModelStoreOwner}
* to automatically restore the Fragment's non configuration state and use
* {@link #restoreSaveState(Parcelable)} to restore the Fragment's save state.
*/
@SuppressWarnings("deprecation")
@Deprecated
public void restoreAllState(@Nullable Parcelable state,
@Nullable FragmentManagerNonConfig nonConfig) {
mHost.mFragmentManager.restoreAllState(state, nonConfig);
}
/**
* Restores the saved state for all Fragments.
*
* @param state the saved state containing the Parcelable returned by {@link #saveAllState()}
* @see #saveAllState()
*/
public void restoreSaveState(@Nullable Parcelable state) {
if (!(mHost instanceof ViewModelStoreOwner)) {
throw new IllegalStateException("Your FragmentHostCallback must implement "
+ "ViewModelStoreOwner to call restoreSaveState(). Call restoreAllState() "
+ " if you're still using retainNestedNonConfig().");
}
mHost.mFragmentManager.restoreSaveState(state);
}
/**
* Returns a list of Fragments that have opted to retain their instance across
* configuration changes.
*
* @deprecated Have your {@link FragmentHostCallback} implement {@link ViewModelStoreOwner}
* to automatically retain the Fragment's non configuration state.
*/
@SuppressWarnings("deprecation")
@Deprecated
@Nullable
public List<Fragment> retainNonConfig() {
FragmentManagerNonConfig nonconf = mHost.mFragmentManager.retainNonConfig();
return nonconf != null && nonconf.getFragments() != null
? new ArrayList<>(nonconf.getFragments())
: null;
}
/**
* Returns a nested tree of Fragments that have opted to retain their instance across
* configuration changes.
*
* @deprecated Have your {@link FragmentHostCallback} implement {@link ViewModelStoreOwner}
* to automatically retain the Fragment's non configuration state.
*/
@SuppressWarnings("deprecation")
@Deprecated
@Nullable
public FragmentManagerNonConfig retainNestedNonConfig() {
return mHost.mFragmentManager.retainNonConfig();
}
/**
* Moves all Fragments managed by the controller's FragmentManager
* into the create state.
* <p>Call when Fragments should be created.
*
* @see Fragment#onCreate(Bundle)
*/
public void dispatchCreate() {
mHost.mFragmentManager.dispatchCreate();
}
/**
* Moves all Fragments managed by the controller's FragmentManager
* into the activity created state.
* <p>Call when Fragments should be informed their host has been created.
*
* @see Fragment#onActivityCreated(Bundle)
*/
public void dispatchActivityCreated() {
mHost.mFragmentManager.dispatchActivityCreated();
}
/**
* Moves all Fragments managed by the controller's FragmentManager
* into the start state.
* <p>Call when Fragments should be started.
*
* @see Fragment#onStart()
*/
public void dispatchStart() {
mHost.mFragmentManager.dispatchStart();
}
/**
* Moves all Fragments managed by the controller's FragmentManager
* into the resume state.
* <p>Call when Fragments should be resumed.
*
* @see Fragment#onResume()
*/
public void dispatchResume() {
mHost.mFragmentManager.dispatchResume();
}
/**
* Moves all Fragments managed by the controller's FragmentManager
* into the pause state.
* <p>Call when Fragments should be paused.
*
* @see Fragment#onPause()
*/
public void dispatchPause() {
mHost.mFragmentManager.dispatchPause();
}
/**
* Moves all Fragments managed by the controller's FragmentManager
* into the stop state.
* <p>Call when Fragments should be stopped.
*
* @see Fragment#onStop()
*/
public void dispatchStop() {
mHost.mFragmentManager.dispatchStop();
}
/**
* @deprecated This functionality has been rolled into {@link #dispatchStop()}.
*/
@Deprecated
public void dispatchReallyStop() {
}
/**
* Moves all Fragments managed by the controller's FragmentManager
* into the destroy view state.
* <p>Call when the Fragment's views should be destroyed.
*
* @see Fragment#onDestroyView()
*/
public void dispatchDestroyView() {
mHost.mFragmentManager.dispatchDestroyView();
}
/**
* Moves Fragments managed by the controller's FragmentManager
* into the destroy state.
* <p>
* If the {@link androidx.fragment.app.FragmentHostCallback} is an instance of {@link ViewModelStoreOwner},
* then retained Fragments and any other non configuration state such as any
* {@link androidx.lifecycle.ViewModel} attached to Fragments will only be destroyed if
* {@link androidx.lifecycle.ViewModelStore#clear()} is called prior to this method.
* <p>
* Otherwise, the FragmentManager will look to see if the
* {@link FragmentHostCallback host's} Context is an {@link Activity}
* and if {@link Activity#isChangingConfigurations()} returns true. In only that case
* will non configuration state be retained.
* <p>Call when Fragments should be destroyed.
*
* @see Fragment#onDestroy()
*/
public void dispatchDestroy() {
mHost.mFragmentManager.dispatchDestroy();
}
/**
* Lets all Fragments managed by the controller's FragmentManager know the multi-window mode of
* the activity changed.
* <p>Call when the multi-window mode of the activity changed.
*
* @see Fragment#onMultiWindowModeChanged
*/
public void dispatchMultiWindowModeChanged(boolean isInMultiWindowMode) {
mHost.mFragmentManager.dispatchMultiWindowModeChanged(isInMultiWindowMode);
}
/**
* Lets all Fragments managed by the controller's FragmentManager know the picture-in-picture
* mode of the activity changed.
* <p>Call when the picture-in-picture mode of the activity changed.
*
* @see Fragment#onPictureInPictureModeChanged
*/
public void dispatchPictureInPictureModeChanged(boolean isInPictureInPictureMode) {
mHost.mFragmentManager.dispatchPictureInPictureModeChanged(isInPictureInPictureMode);
}
/**
* Lets all Fragments managed by the controller's FragmentManager
* know a configuration change occurred.
* <p>Call when there is a configuration change.
*
* @see Fragment#onConfigurationChanged(Configuration)
*/
public void dispatchConfigurationChanged(@NonNull Configuration newConfig) {
mHost.mFragmentManager.dispatchConfigurationChanged(newConfig);
}
/**
* Lets all Fragments managed by the controller's FragmentManager
* know the device is in a low memory condition.
* <p>Call when the device is low on memory and Fragment's should trim
* their memory usage.
*
* @see Fragment#onLowMemory()
*/
public void dispatchLowMemory() {
mHost.mFragmentManager.dispatchLowMemory();
}
/**
* Lets all Fragments managed by the controller's FragmentManager
* know they should create an options menu.
* <p>Call when the Fragment should create an options menu.
*
* @return {@code true} if the options menu contains items to display
* @see Fragment#onCreateOptionsMenu(Menu, MenuInflater)
*/
public boolean dispatchCreateOptionsMenu(@NonNull Menu menu, @NonNull MenuInflater inflater) {
return mHost.mFragmentManager.dispatchCreateOptionsMenu(menu, inflater);
}
/**
* Lets all Fragments managed by the controller's FragmentManager
* know they should prepare their options menu for display.
* <p>Call immediately before displaying the Fragment's options menu.
*
* @return {@code true} if the options menu contains items to display
* @see Fragment#onPrepareOptionsMenu(Menu)
*/
public boolean dispatchPrepareOptionsMenu(@NonNull Menu menu) {
return mHost.mFragmentManager.dispatchPrepareOptionsMenu(menu);
}
/**
* Sends an option item selection event to the Fragments managed by the
* controller's FragmentManager. Once the event has been consumed,
* no additional handling will be performed.
* <p>Call immediately after an options menu item has been selected
*
* @return {@code true} if the options menu selection event was consumed
* @see Fragment#onOptionsItemSelected(MenuItem)
*/
public boolean dispatchOptionsItemSelected(@NonNull MenuItem item) {
return mHost.mFragmentManager.dispatchOptionsItemSelected(item);
}
/**
* Sends a context item selection event to the Fragments managed by the
* controller's FragmentManager. Once the event has been consumed,
* no additional handling will be performed.
* <p>Call immediately after an options menu item has been selected
*
* @return {@code true} if the context menu selection event was consumed
* @see Fragment#onContextItemSelected(MenuItem)
*/
public boolean dispatchContextItemSelected(@NonNull MenuItem item) {
return mHost.mFragmentManager.dispatchContextItemSelected(item);
}
/**
* Lets all Fragments managed by the controller's FragmentManager
* know their options menu has closed.
* <p>Call immediately after closing the Fragment's options menu.
*
* @see Fragment#onOptionsMenuClosed(Menu)
*/
public void dispatchOptionsMenuClosed(@NonNull Menu menu) {
mHost.mFragmentManager.dispatchOptionsMenuClosed(menu);
}
/**
* Execute any pending actions for the Fragments managed by the
* controller's FragmentManager.
* <p>Call when queued actions can be performed [eg when the
* Fragment moves into a start or resume state].
* @return {@code true} if queued actions were performed
*/
public boolean execPendingActions() {
return mHost.mFragmentManager.execPendingActions(true);
}
/**
* Starts the loaders.
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
public void doLoaderStart() {
}
/**
* Stops the loaders, optionally retaining their state. This is useful for keeping the
* loader state across configuration changes.
*
* @param retain When {@code true}, the loaders aren't stopped, but, their instances
* are retained in a started state
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
public void doLoaderStop(boolean retain) {
}
/**
* Retains the state of each of the loaders.
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
public void doLoaderRetain() {
}
/**
* Destroys the loaders and, if their state is not being retained, removes them.
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
public void doLoaderDestroy() {
}
/**
* Lets the loaders know the host is ready to receive notifications.
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
public void reportLoaderStart() {
}
/**
* Returns a list of LoaderManagers that have opted to retain their instance across
* configuration changes.
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
@Nullable
public SimpleArrayMap<String, LoaderManager> retainLoaderNonConfig() {
return null;
}
/**
* Restores the saved state for all LoaderManagers. The given LoaderManager list are
* LoaderManager instances retained across configuration changes.
*
* @see #retainLoaderNonConfig()
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
public void restoreLoaderNonConfig(@SuppressLint("UnknownNullness")
SimpleArrayMap<String, LoaderManager> loaderManagers) {
}
/**
* Dumps the current state of the loaders.
*
* @deprecated Loaders are managed separately from FragmentController
*/
@Deprecated
public void dumpLoaders(@NonNull String prefix, @Nullable FileDescriptor fd,
@NonNull PrintWriter writer, @Nullable String[] args) {
}
}