1/* 2 * Copyright (C) 2011 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 17package android.support.v4.view; 18 19import android.os.Build; 20import android.view.View; 21import android.view.ViewGroup; 22import android.view.accessibility.AccessibilityEvent; 23 24/** 25 * Helper for accessing features in {@link ViewGroup} 26 * introduced after API level 4 in a backwards compatible fashion. 27 */ 28public class ViewGroupCompat { 29 30 interface ViewGroupCompatImpl { 31 public boolean onRequestSendAccessibilityEvent(ViewGroup group, View child, 32 AccessibilityEvent event); 33 } 34 35 static class ViewGroupCompatStubImpl implements ViewGroupCompatImpl { 36 public boolean onRequestSendAccessibilityEvent( 37 ViewGroup group, View child, AccessibilityEvent event) { 38 return true; 39 } 40 } 41 42 static class ViewGroupCompatIcsImpl extends ViewGroupCompatStubImpl { 43 @Override 44 public boolean onRequestSendAccessibilityEvent( 45 ViewGroup group, View child, AccessibilityEvent event) { 46 return ViewGroupCompatIcs.onRequestSendAccessibilityEvent(group, child, event); 47 } 48 } 49 50 static final ViewGroupCompatImpl IMPL; 51 static { 52 if (Build.VERSION.SDK_INT >= 14) { 53 IMPL = new ViewGroupCompatIcsImpl(); 54 } else { 55 IMPL = new ViewGroupCompatStubImpl(); 56 } 57 } 58 59 /* 60 * Hide the constructor. 61 */ 62 private ViewGroupCompat() { 63 64 } 65 66 /** 67 * Called when a child has requested sending an {@link AccessibilityEvent} and 68 * gives an opportunity to its parent to augment the event. 69 * <p> 70 * If an {@link AccessibilityDelegateCompat} has been specified via calling 71 * {@link ViewCompat#setAccessibilityDelegate(View, AccessibilityDelegateCompat)} its 72 * {@link AccessibilityDelegateCompat#onRequestSendAccessibilityEvent(ViewGroup, View, 73 * AccessibilityEvent)} is responsible for handling this call. 74 * </p> 75 * 76 * @param group The group whose method to invoke. 77 * @param child The child which requests sending the event. 78 * @param event The event to be sent. 79 * @return True if the event should be sent. 80 */ 81 public static boolean onRequestSendAccessibilityEvent(ViewGroup group, View child, 82 AccessibilityEvent event) { 83 return IMPL.onRequestSendAccessibilityEvent(group, child, event); 84 } 85} 86