1 /* 2 * Copyright (C) 2022 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.window; 18 19 import android.app.Activity; 20 import android.app.Dialog; 21 import android.view.View; 22 import android.view.Window; 23 24 /** 25 * Callback allowing applications to handle back events in place of the system. 26 * <p> 27 * Callback instances can be added to and removed from {@link OnBackInvokedDispatcher}, which 28 * is held at window level and accessible through {@link Activity#getOnBackInvokedDispatcher()}, 29 * {@link Dialog#getOnBackInvokedDispatcher()}, {@link Window#getOnBackInvokedDispatcher()} 30 * and {@link View#findOnBackInvokedDispatcher()}. 31 * <p> 32 * When back is triggered, callbacks on the in-focus window are invoked in reverse order in which 33 * they are added within the same priority. Between different priorities, callbacks with higher 34 * priority are invoked first. 35 * <p> 36 * This replaces {@link Activity#onBackPressed()}, {@link Dialog#onBackPressed()} and 37 * {@link android.view.KeyEvent#KEYCODE_BACK} 38 * <p> 39 * If you want to customize back animation behaviors, in addition to handling back invocations, 40 * register its subclass instances {@link OnBackAnimationCallback} instead. 41 * <p> 42 * @see OnBackInvokedDispatcher#registerOnBackInvokedCallback(int, OnBackInvokedCallback) 43 * registerOnBackInvokedCallback(priority, OnBackInvokedCallback) 44 * to specify callback priority. 45 */ 46 @SuppressWarnings("deprecation") 47 public interface OnBackInvokedCallback { 48 /** 49 * Called when a back gesture has been completed and committed, or back button pressed 50 * has been released and committed. 51 */ onBackInvoked()52 void onBackInvoked(); 53 } 54