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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 com.android.annotations.NonNull;
     20 
     21 import android.accessibilityservice.AccessibilityServiceInfo;
     22 import android.content.Context;
     23 import android.content.pm.ServiceInfo;
     24 import android.view.IWindow;
     25 import android.view.View;
     26 
     27 import java.util.Collections;
     28 import java.util.List;
     29 
     30 /**
     31  * System level service that serves as an event dispatch for {@link AccessibilityEvent}s.
     32  * Such events are generated when something notable happens in the user interface,
     33  * for example an {@link android.app.Activity} starts, the focus or selection of a
     34  * {@link android.view.View} changes etc. Parties interested in handling accessibility
     35  * events implement and register an accessibility service which extends
     36  * {@code android.accessibilityservice.AccessibilityService}.
     37  *
     38  * @see AccessibilityEvent
     39  * @see android.content.Context#getSystemService
     40  */
     41 @SuppressWarnings("UnusedDeclaration")
     42 public final class AccessibilityManager {
     43 
     44     private static AccessibilityManager sInstance = new AccessibilityManager(null, null, 0);
     45 
     46 
     47     /**
     48      * Listener for the accessibility state.
     49      */
     50     public interface AccessibilityStateChangeListener {
     51 
     52         /**
     53          * Called back on change in the accessibility state.
     54          *
     55          * @param enabled Whether accessibility is enabled.
     56          */
     57         public void onAccessibilityStateChanged(boolean enabled);
     58     }
     59 
     60     /**
     61      * Listener for the system touch exploration state. To listen for changes to
     62      * the touch exploration state on the device, implement this interface and
     63      * register it with the system by calling
     64      * {@link #addTouchExplorationStateChangeListener}.
     65      */
     66     public interface TouchExplorationStateChangeListener {
     67 
     68         /**
     69          * Called when the touch exploration enabled state changes.
     70          *
     71          * @param enabled Whether touch exploration is enabled.
     72          */
     73         public void onTouchExplorationStateChanged(boolean enabled);
     74     }
     75 
     76     /**
     77      * Listener for the system high text contrast state. To listen for changes to
     78      * the high text contrast state on the device, implement this interface and
     79      * register it with the system by calling
     80      * {@link #addHighTextContrastStateChangeListener}.
     81      */
     82     public interface HighTextContrastChangeListener {
     83 
     84         /**
     85          * Called when the high text contrast enabled state changes.
     86          *
     87          * @param enabled Whether high text contrast is enabled.
     88          */
     89         public void onHighTextContrastStateChanged(boolean enabled);
     90     }
     91 
     92     private final IAccessibilityManagerClient.Stub mClient =
     93             new IAccessibilityManagerClient.Stub() {
     94                 public void setState(int state) {
     95                 }
     96             };
     97 
     98     /**
     99      * Get an AccessibilityManager instance (create one if necessary).
    100      *
    101      */
    102     public static AccessibilityManager getInstance(Context context) {
    103         return sInstance;
    104     }
    105 
    106     /**
    107      * Create an instance.
    108      *
    109      * @param context A {@link Context}.
    110      */
    111     public AccessibilityManager(Context context, IAccessibilityManager service, int userId) {
    112     }
    113 
    114     public IAccessibilityManagerClient getClient() {
    115         return mClient;
    116     }
    117 
    118     /**
    119      * Returns if the {@link AccessibilityManager} is enabled.
    120      *
    121      * @return True if this {@link AccessibilityManager} is enabled, false otherwise.
    122      */
    123     public boolean isEnabled() {
    124         return false;
    125     }
    126 
    127     /**
    128      * Returns if the touch exploration in the system is enabled.
    129      *
    130      * @return True if touch exploration is enabled, false otherwise.
    131      */
    132     public boolean isTouchExplorationEnabled() {
    133         return true;
    134     }
    135 
    136     /**
    137      * Returns if the high text contrast in the system is enabled.
    138      * <p>
    139      * <strong>Note:</strong> You need to query this only if you application is
    140      * doing its own rendering and does not rely on the platform rendering pipeline.
    141      * </p>
    142      *
    143      */
    144     public boolean isHighTextContrastEnabled() {
    145         return false;
    146     }
    147 
    148     /**
    149      * Sends an {@link AccessibilityEvent}.
    150      */
    151     public void sendAccessibilityEvent(AccessibilityEvent event) {
    152     }
    153 
    154     /**
    155      * Requests interruption of the accessibility feedback from all accessibility services.
    156      */
    157     public void interrupt() {
    158     }
    159 
    160     /**
    161      * Returns the {@link ServiceInfo}s of the installed accessibility services.
    162      *
    163      * @return An unmodifiable list with {@link ServiceInfo}s.
    164      */
    165     @Deprecated
    166     public List<ServiceInfo> getAccessibilityServiceList() {
    167         return Collections.emptyList();
    168     }
    169 
    170     public List<AccessibilityServiceInfo> getInstalledAccessibilityServiceList() {
    171         return Collections.emptyList();
    172     }
    173 
    174     /**
    175      * Returns the {@link AccessibilityServiceInfo}s of the enabled accessibility services
    176      * for a given feedback type.
    177      *
    178      * @param feedbackTypeFlags The feedback type flags.
    179      * @return An unmodifiable list with {@link AccessibilityServiceInfo}s.
    180      *
    181      * @see AccessibilityServiceInfo#FEEDBACK_AUDIBLE
    182      * @see AccessibilityServiceInfo#FEEDBACK_GENERIC
    183      * @see AccessibilityServiceInfo#FEEDBACK_HAPTIC
    184      * @see AccessibilityServiceInfo#FEEDBACK_SPOKEN
    185      * @see AccessibilityServiceInfo#FEEDBACK_VISUAL
    186      */
    187     public List<AccessibilityServiceInfo> getEnabledAccessibilityServiceList(
    188             int feedbackTypeFlags) {
    189         return Collections.emptyList();
    190     }
    191 
    192     /**
    193      * Registers an {@link AccessibilityStateChangeListener} for changes in
    194      * the global accessibility state of the system.
    195      *
    196      * @param listener The listener.
    197      * @return True if successfully registered.
    198      */
    199     public boolean addAccessibilityStateChangeListener(
    200             AccessibilityStateChangeListener listener) {
    201         return true;
    202     }
    203 
    204     public boolean removeAccessibilityStateChangeListener(
    205             AccessibilityStateChangeListener listener) {
    206         return true;
    207     }
    208 
    209     /**
    210      * Registers a {@link TouchExplorationStateChangeListener} for changes in
    211      * the global touch exploration state of the system.
    212      *
    213      * @param listener The listener.
    214      * @return True if successfully registered.
    215      */
    216     public boolean addTouchExplorationStateChangeListener(
    217             @NonNull TouchExplorationStateChangeListener listener) {
    218         return true;
    219     }
    220 
    221     /**
    222      * Unregisters a {@link TouchExplorationStateChangeListener}.
    223      *
    224      * @param listener The listener.
    225      * @return True if successfully unregistered.
    226      */
    227     public boolean removeTouchExplorationStateChangeListener(
    228             @NonNull TouchExplorationStateChangeListener listener) {
    229         return true;
    230     }
    231 
    232     /**
    233      * Registers a {@link HighTextContrastChangeListener} for changes in
    234      * the global high text contrast state of the system.
    235      *
    236      * @param listener The listener.
    237      * @return True if successfully registered.
    238      *
    239      */
    240     public boolean addHighTextContrastStateChangeListener(
    241             @NonNull HighTextContrastChangeListener listener) {
    242         return true;
    243     }
    244 
    245     /**
    246      * Unregisters a {@link HighTextContrastChangeListener}.
    247      *
    248      * @param listener The listener.
    249      * @return True if successfully unregistered.
    250      *
    251      */
    252     public boolean removeHighTextContrastStateChangeListener(
    253             @NonNull HighTextContrastChangeListener listener) {
    254         return true;
    255     }
    256 
    257     /**
    258      * Sets the current state and notifies listeners, if necessary.
    259      *
    260      * @param stateFlags The state flags.
    261      */
    262     private void setStateLocked(int stateFlags) {
    263     }
    264 
    265     public int addAccessibilityInteractionConnection(IWindow windowToken,
    266             IAccessibilityInteractionConnection connection) {
    267         return View.NO_ID;
    268     }
    269 
    270     public void removeAccessibilityInteractionConnection(IWindow windowToken) {
    271     }
    272 
    273 }
    274