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      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.annotation.NonNull;
     21 import android.content.Context;
     22 import android.content.pm.ServiceInfo;
     23 import android.view.IWindow;
     24 import android.view.View;
     25 
     26 import java.util.Collections;
     27 import java.util.List;
     28 
     29 /**
     30  * System level service that serves as an event dispatch for {@link AccessibilityEvent}s.
     31  * Such events are generated when something notable happens in the user interface,
     32  * for example an {@link android.app.Activity} starts, the focus or selection of a
     33  * {@link android.view.View} changes etc. Parties interested in handling accessibility
     34  * events implement and register an accessibility service which extends
     35  * {@code android.accessibilityservice.AccessibilityService}.
     36  *
     37  * @see AccessibilityEvent
     38  * @see android.content.Context#getSystemService
     39  */
     40 @SuppressWarnings("UnusedDeclaration")
     41 public final class AccessibilityManager {
     42 
     43     private static AccessibilityManager sInstance = new AccessibilityManager(null, null, 0);
     44 
     45 
     46     /**
     47      * Listener for the accessibility state.
     48      */
     49     public interface AccessibilityStateChangeListener {
     50 
     51         /**
     52          * Called back on change in the accessibility state.
     53          *
     54          * @param enabled Whether accessibility is enabled.
     55          */
     56         public void onAccessibilityStateChanged(boolean enabled);
     57     }
     58 
     59     /**
     60      * Listener for the system touch exploration state. To listen for changes to
     61      * the touch exploration state on the device, implement this interface and
     62      * register it with the system by calling
     63      * {@link #addTouchExplorationStateChangeListener}.
     64      */
     65     public interface TouchExplorationStateChangeListener {
     66 
     67         /**
     68          * Called when the touch exploration enabled state changes.
     69          *
     70          * @param enabled Whether touch exploration is enabled.
     71          */
     72         public void onTouchExplorationStateChanged(boolean enabled);
     73     }
     74 
     75     /**
     76      * Listener for the system high text contrast state. To listen for changes to
     77      * the high text contrast state on the device, implement this interface and
     78      * register it with the system by calling
     79      * {@link #addHighTextContrastStateChangeListener}.
     80      */
     81     public interface HighTextContrastChangeListener {
     82 
     83         /**
     84          * Called when the high text contrast enabled state changes.
     85          *
     86          * @param enabled Whether high text contrast is enabled.
     87          */
     88         public void onHighTextContrastStateChanged(boolean enabled);
     89     }
     90 
     91     private final IAccessibilityManagerClient.Stub mClient =
     92             new IAccessibilityManagerClient.Stub() {
     93                 public void setState(int state) {
     94                 }
     95             };
     96 
     97     /**
     98      * Get an AccessibilityManager instance (create one if necessary).
     99      *
    100      */
    101     public static AccessibilityManager getInstance(Context context) {
    102         return sInstance;
    103     }
    104 
    105     /**
    106      * Create an instance.
    107      *
    108      * @param context A {@link Context}.
    109      */
    110     public AccessibilityManager(Context context, IAccessibilityManager service, int userId) {
    111     }
    112 
    113     public IAccessibilityManagerClient getClient() {
    114         return mClient;
    115     }
    116 
    117     /**
    118      * Returns if the {@link AccessibilityManager} is enabled.
    119      *
    120      * @return True if this {@link AccessibilityManager} is enabled, false otherwise.
    121      */
    122     public boolean isEnabled() {
    123         return false;
    124     }
    125 
    126     /**
    127      * Returns if the touch exploration in the system is enabled.
    128      *
    129      * @return True if touch exploration is enabled, false otherwise.
    130      */
    131     public boolean isTouchExplorationEnabled() {
    132         return true;
    133     }
    134 
    135     /**
    136      * Returns if the high text contrast in the system is enabled.
    137      * <p>
    138      * <strong>Note:</strong> You need to query this only if you application is
    139      * doing its own rendering and does not rely on the platform rendering pipeline.
    140      * </p>
    141      *
    142      */
    143     public boolean isHighTextContrastEnabled() {
    144         return false;
    145     }
    146 
    147     /**
    148      * Sends an {@link AccessibilityEvent}.
    149      */
    150     public void sendAccessibilityEvent(AccessibilityEvent event) {
    151     }
    152 
    153     /**
    154      * Requests interruption of the accessibility feedback from all accessibility services.
    155      */
    156     public void interrupt() {
    157     }
    158 
    159     /**
    160      * Returns the {@link ServiceInfo}s of the installed accessibility services.
    161      *
    162      * @return An unmodifiable list with {@link ServiceInfo}s.
    163      */
    164     @Deprecated
    165     public List<ServiceInfo> getAccessibilityServiceList() {
    166         return Collections.emptyList();
    167     }
    168 
    169     public List<AccessibilityServiceInfo> getInstalledAccessibilityServiceList() {
    170         return Collections.emptyList();
    171     }
    172 
    173     /**
    174      * Returns the {@link AccessibilityServiceInfo}s of the enabled accessibility services
    175      * for a given feedback type.
    176      *
    177      * @param feedbackTypeFlags The feedback type flags.
    178      * @return An unmodifiable list with {@link AccessibilityServiceInfo}s.
    179      *
    180      * @see AccessibilityServiceInfo#FEEDBACK_AUDIBLE
    181      * @see AccessibilityServiceInfo#FEEDBACK_GENERIC
    182      * @see AccessibilityServiceInfo#FEEDBACK_HAPTIC
    183      * @see AccessibilityServiceInfo#FEEDBACK_SPOKEN
    184      * @see AccessibilityServiceInfo#FEEDBACK_VISUAL
    185      */
    186     public List<AccessibilityServiceInfo> getEnabledAccessibilityServiceList(
    187             int feedbackTypeFlags) {
    188         return Collections.emptyList();
    189     }
    190 
    191     /**
    192      * Registers an {@link AccessibilityStateChangeListener} for changes in
    193      * the global accessibility state of the system.
    194      *
    195      * @param listener The listener.
    196      * @return True if successfully registered.
    197      */
    198     public boolean addAccessibilityStateChangeListener(
    199             AccessibilityStateChangeListener listener) {
    200         return true;
    201     }
    202 
    203     public boolean removeAccessibilityStateChangeListener(
    204             AccessibilityStateChangeListener listener) {
    205         return true;
    206     }
    207 
    208     /**
    209      * Registers a {@link TouchExplorationStateChangeListener} for changes in
    210      * the global touch exploration state of the system.
    211      *
    212      * @param listener The listener.
    213      * @return True if successfully registered.
    214      */
    215     public boolean addTouchExplorationStateChangeListener(
    216             @NonNull TouchExplorationStateChangeListener listener) {
    217         return true;
    218     }
    219 
    220     /**
    221      * Unregisters a {@link TouchExplorationStateChangeListener}.
    222      *
    223      * @param listener The listener.
    224      * @return True if successfully unregistered.
    225      */
    226     public boolean removeTouchExplorationStateChangeListener(
    227             @NonNull TouchExplorationStateChangeListener listener) {
    228         return true;
    229     }
    230 
    231     /**
    232      * Registers a {@link HighTextContrastChangeListener} for changes in
    233      * the global high text contrast state of the system.
    234      *
    235      * @param listener The listener.
    236      * @return True if successfully registered.
    237      *
    238      */
    239     public boolean addHighTextContrastStateChangeListener(
    240             @NonNull HighTextContrastChangeListener listener) {
    241         return true;
    242     }
    243 
    244     /**
    245      * Unregisters a {@link HighTextContrastChangeListener}.
    246      *
    247      * @param listener The listener.
    248      * @return True if successfully unregistered.
    249      *
    250      */
    251     public boolean removeHighTextContrastStateChangeListener(
    252             @NonNull HighTextContrastChangeListener listener) {
    253         return true;
    254     }
    255 
    256     /**
    257      * Sets the current state and notifies listeners, if necessary.
    258      *
    259      * @param stateFlags The state flags.
    260      */
    261     private void setStateLocked(int stateFlags) {
    262     }
    263 
    264     public int addAccessibilityInteractionConnection(IWindow windowToken,
    265             IAccessibilityInteractionConnection connection) {
    266         return View.NO_ID;
    267     }
    268 
    269     public void removeAccessibilityInteractionConnection(IWindow windowToken) {
    270     }
    271 
    272 }
    273