android-35/android/window/OnBackInvokedCallback.java

/*
 * Copyright (C) 2022 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 android.window;

import android.app.Activity;
import android.app.Dialog;
import android.view.View;
import android.view.Window;

/**
 * Callback allowing applications to handle back events in place of the system.
 * <p>
 * Callback instances can be added to and removed from {@link OnBackInvokedDispatcher}, which
 * is held at window level and accessible through {@link Activity#getOnBackInvokedDispatcher()},
 * {@link Dialog#getOnBackInvokedDispatcher()}, {@link Window#getOnBackInvokedDispatcher()}
 * and {@link View#findOnBackInvokedDispatcher()}.
 * <p>
 * When back is triggered, callbacks on the in-focus window are invoked in reverse order in which
 * they are added within the same priority. Between different priorities, callbacks with higher
 * priority are invoked first.
 * <p>
 * This replaces {@link Activity#onBackPressed()}, {@link Dialog#onBackPressed()} and
 * {@link android.view.KeyEvent#KEYCODE_BACK}
 * <p>
 * If you want to customize back animation behaviors, in addition to handling back invocations,
 * register its subclass instances {@link OnBackAnimationCallback} instead.
 * <p>
 * @see OnBackInvokedDispatcher#registerOnBackInvokedCallback(int, OnBackInvokedCallback)
 * registerOnBackInvokedCallback(priority, OnBackInvokedCallback)
 * to specify callback priority.
 */
@SuppressWarnings("deprecation")
public interface OnBackInvokedCallback {
    /**
     * Called when a back gesture has been completed and committed, or back button pressed
     * has been released and committed.
     */
    void onBackInvoked();
}