1 /* 2 * Copyright (C) 2017 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 com.android.documentsui.dirlist; 18 19 import android.os.Bundle; 20 import android.support.v4.view.AccessibilityDelegateCompat; 21 import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat; 22 import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat.AccessibilityActionCompat; 23 import android.support.v7.widget.RecyclerView; 24 import android.support.v7.widget.RecyclerViewAccessibilityDelegate; 25 import android.view.View; 26 27 import java.util.function.Function; 28 29 /** 30 * Custom Accessibility Delegate for RecyclerViews to route click events on its child views to 31 * proper handlers, and to surface selection state to a11y events. 32 * <p> 33 * The majority of event handling isdone using TouchDetector instead of View.OnCLickListener, which 34 * most a11y services use to understand whether a particular view is clickable or not. Thus, we need 35 * to use a custom accessibility delegate to manually add ACTION_CLICK to clickable child views' 36 * accessibility node, and then correctly route these clicks done by a11y services to responsible 37 * click callbacks. 38 * <p> 39 * DocumentsUI uses {@link View#setActivated(boolean)} instead of {@link View#setSelected(boolean)} 40 * for marking a view as selected. We will surface that selection state to a11y services in this 41 * class. 42 */ 43 public class AccessibilityEventRouter extends RecyclerViewAccessibilityDelegate { 44 45 private final ItemDelegate mItemDelegate; 46 private final Function<View, Boolean> mClickCallback; 47 AccessibilityEventRouter( RecyclerView recyclerView, Function<View, Boolean> clickCallback)48 public AccessibilityEventRouter( 49 RecyclerView recyclerView, Function<View, Boolean> clickCallback) { 50 super(recyclerView); 51 mClickCallback = clickCallback; 52 mItemDelegate = new ItemDelegate(this) { 53 @Override 54 public void onInitializeAccessibilityNodeInfo(View host, 55 AccessibilityNodeInfoCompat info) { 56 super.onInitializeAccessibilityNodeInfo(host, info); 57 info.addAction(AccessibilityActionCompat.ACTION_CLICK); 58 info.setSelected(host.isActivated()); 59 } 60 61 @Override 62 public boolean performAccessibilityAction(View host, int action, Bundle args) { 63 // We are only handling click events; route all other to default implementation 64 if (action == AccessibilityNodeInfoCompat.ACTION_CLICK) { 65 return mClickCallback.apply(host); 66 } 67 return super.performAccessibilityAction(host, action, args); 68 } 69 }; 70 } 71 72 @Override getItemDelegate()73 public AccessibilityDelegateCompat getItemDelegate() { 74 return mItemDelegate; 75 } 76 }