1 /* 2 * Copyright (C) 2009 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.view.accessibility; 18 19 import android.accessibilityservice.AccessibilityServiceInfo; 20 import android.content.Context; 21 import android.content.pm.ServiceInfo; 22 import android.view.IWindow; 23 import android.view.View; 24 25 import java.util.Collections; 26 import java.util.List; 27 28 /** 29 * System level service that serves as an event dispatch for {@link AccessibilityEvent}s. 30 * Such events are generated when something notable happens in the user interface, 31 * for example an {@link android.app.Activity} starts, the focus or selection of a 32 * {@link android.view.View} changes etc. Parties interested in handling accessibility 33 * events implement and register an accessibility service which extends 34 * {@link android.accessibilityservice.AccessibilityService}. 35 * 36 * @see AccessibilityEvent 37 * @see android.accessibilityservice.AccessibilityService 38 * @see android.content.Context#getSystemService 39 */ 40 public final class AccessibilityManager { 41 private static AccessibilityManager sInstance = new AccessibilityManager(); 42 43 /** 44 * Listener for the accessibility state. 45 */ 46 public interface AccessibilityStateChangeListener { 47 48 /** 49 * Called back on change in the accessibility state. 50 * 51 * @param enabled Whether accessibility is enabled. 52 */ onAccessibilityStateChanged(boolean enabled)53 public void onAccessibilityStateChanged(boolean enabled); 54 } 55 56 /** 57 * Get an AccessibilityManager instance (create one if necessary). 58 * 59 * @hide 60 */ getInstance(Context context)61 public static AccessibilityManager getInstance(Context context) { 62 return sInstance; 63 } 64 65 /** 66 * Create an instance. 67 * 68 * @param context A {@link Context}. 69 */ AccessibilityManager()70 private AccessibilityManager() { 71 } 72 73 /** 74 * Returns if the {@link AccessibilityManager} is enabled. 75 * 76 * @return True if this {@link AccessibilityManager} is enabled, false otherwise. 77 */ isEnabled()78 public boolean isEnabled() { 79 return false; 80 } 81 82 /** 83 * Sends an {@link AccessibilityEvent}. If this {@link AccessibilityManager} is not 84 * enabled the call is a NOOP. 85 * 86 * @param event The {@link AccessibilityEvent}. 87 * 88 * @throws IllegalStateException if a client tries to send an {@link AccessibilityEvent} 89 * while accessibility is not enabled. 90 */ sendAccessibilityEvent(AccessibilityEvent event)91 public void sendAccessibilityEvent(AccessibilityEvent event) { 92 } 93 94 /** 95 * Requests interruption of the accessibility feedback from all accessibility services. 96 */ interrupt()97 public void interrupt() { 98 } 99 100 /** 101 * Returns the {@link ServiceInfo}s of the installed accessibility services. 102 * 103 * @return An unmodifiable list with {@link ServiceInfo}s. 104 */ getAccessibilityServiceList()105 public List<ServiceInfo> getAccessibilityServiceList() { 106 // normal implementation does this in some case, so let's do the same 107 // (unmodifiableList wrapped around null). 108 List<ServiceInfo> services = null; 109 return Collections.unmodifiableList(services); 110 } 111 getInstalledAccessibilityServiceList()112 public List<AccessibilityServiceInfo> getInstalledAccessibilityServiceList() { 113 // normal implementation does this in some case, so let's do the same 114 // (unmodifiableList wrapped around null). 115 List<AccessibilityServiceInfo> services = null; 116 return Collections.unmodifiableList(services); 117 } 118 addAccessibilityStateChangeListener( AccessibilityStateChangeListener listener)119 public boolean addAccessibilityStateChangeListener( 120 AccessibilityStateChangeListener listener) { 121 return true; 122 } 123 removeAccessibilityStateChangeListener( AccessibilityStateChangeListener listener)124 public boolean removeAccessibilityStateChangeListener( 125 AccessibilityStateChangeListener listener) { 126 return true; 127 } 128 addAccessibilityInteractionConnection(IWindow windowToken, IAccessibilityInteractionConnection connection)129 public int addAccessibilityInteractionConnection(IWindow windowToken, 130 IAccessibilityInteractionConnection connection) { 131 return View.NO_ID; 132 } 133 removeAccessibilityInteractionConnection(IWindow windowToken)134 public void removeAccessibilityInteractionConnection(IWindow windowToken) { 135 } 136 137 } 138