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 
17 package com.android.inputmethod.accessibility;
18 
19 import android.content.Context;
20 import android.media.AudioManager;
21 import android.os.Build;
22 import android.os.SystemClock;
23 import android.provider.Settings;
24 import android.support.v4.view.accessibility.AccessibilityEventCompat;
25 import android.text.TextUtils;
26 import android.util.Log;
27 import android.view.MotionEvent;
28 import android.view.View;
29 import android.view.ViewGroup;
30 import android.view.ViewParent;
31 import android.view.accessibility.AccessibilityEvent;
32 import android.view.accessibility.AccessibilityManager;
33 import android.view.inputmethod.EditorInfo;
34 
35 import com.android.inputmethod.compat.SettingsSecureCompatUtils;
36 import com.android.inputmethod.latin.R;
37 import com.android.inputmethod.latin.SuggestedWords;
38 import com.android.inputmethod.latin.utils.InputTypeUtils;
39 
40 public final class AccessibilityUtils {
41     private static final String TAG = AccessibilityUtils.class.getSimpleName();
42     private static final String CLASS = AccessibilityUtils.class.getClass().getName();
43     private static final String PACKAGE =
44             AccessibilityUtils.class.getClass().getPackage().getName();
45 
46     private static final AccessibilityUtils sInstance = new AccessibilityUtils();
47 
48     private Context mContext;
49     private AccessibilityManager mAccessibilityManager;
50     private AudioManager mAudioManager;
51 
52     /** The most recent auto-correction. */
53     private String mAutoCorrectionWord;
54 
55     /** The most recent typed word for auto-correction. */
56     private String mTypedWord;
57 
58     /*
59      * Setting this constant to {@code false} will disable all keyboard
60      * accessibility code, regardless of whether Accessibility is turned on in
61      * the system settings. It should ONLY be used in the event of an emergency.
62      */
63     private static final boolean ENABLE_ACCESSIBILITY = true;
64 
init(final Context context)65     public static void init(final Context context) {
66         if (!ENABLE_ACCESSIBILITY) return;
67 
68         // These only need to be initialized if the kill switch is off.
69         sInstance.initInternal(context);
70     }
71 
getInstance()72     public static AccessibilityUtils getInstance() {
73         return sInstance;
74     }
75 
AccessibilityUtils()76     private AccessibilityUtils() {
77         // This class is not publicly instantiable.
78     }
79 
initInternal(final Context context)80     private void initInternal(final Context context) {
81         mContext = context;
82         mAccessibilityManager =
83                 (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE);
84         mAudioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
85     }
86 
87     /**
88      * Returns {@code true} if accessibility is enabled. Currently, this means
89      * that the kill switch is off and system accessibility is turned on.
90      *
91      * @return {@code true} if accessibility is enabled.
92      */
isAccessibilityEnabled()93     public boolean isAccessibilityEnabled() {
94         return ENABLE_ACCESSIBILITY && mAccessibilityManager.isEnabled();
95     }
96 
97     /**
98      * Returns {@code true} if touch exploration is enabled. Currently, this
99      * means that the kill switch is off, the device supports touch exploration,
100      * and system accessibility is turned on.
101      *
102      * @return {@code true} if touch exploration is enabled.
103      */
isTouchExplorationEnabled()104     public boolean isTouchExplorationEnabled() {
105         return isAccessibilityEnabled() && mAccessibilityManager.isTouchExplorationEnabled();
106     }
107 
108     /**
109      * Returns {@true} if the provided event is a touch exploration (e.g. hover)
110      * event. This is used to determine whether the event should be processed by
111      * the touch exploration code within the keyboard.
112      *
113      * @param event The event to check.
114      * @return {@true} is the event is a touch exploration event
115      */
isTouchExplorationEvent(final MotionEvent event)116     public static boolean isTouchExplorationEvent(final MotionEvent event) {
117         final int action = event.getAction();
118         return action == MotionEvent.ACTION_HOVER_ENTER
119                 || action == MotionEvent.ACTION_HOVER_EXIT
120                 || action == MotionEvent.ACTION_HOVER_MOVE;
121     }
122 
123     /**
124      * Returns whether the device should obscure typed password characters.
125      * Typically this means speaking "dot" in place of non-control characters.
126      *
127      * @return {@code true} if the device should obscure password characters.
128      */
129     @SuppressWarnings("deprecation")
shouldObscureInput(final EditorInfo editorInfo)130     public boolean shouldObscureInput(final EditorInfo editorInfo) {
131         if (editorInfo == null) return false;
132 
133         // The user can optionally force speaking passwords.
134         if (SettingsSecureCompatUtils.ACCESSIBILITY_SPEAK_PASSWORD != null) {
135             final boolean speakPassword = Settings.Secure.getInt(mContext.getContentResolver(),
136                     SettingsSecureCompatUtils.ACCESSIBILITY_SPEAK_PASSWORD, 0) != 0;
137             if (speakPassword) return false;
138         }
139 
140         // Always speak if the user is listening through headphones.
141         if (mAudioManager.isWiredHeadsetOn() || mAudioManager.isBluetoothA2dpOn()) {
142             return false;
143         }
144 
145         // Don't speak if the IME is connected to a password field.
146         return InputTypeUtils.isPasswordInputType(editorInfo.inputType);
147     }
148 
149     /**
150      * Sets the current auto-correction word and typed word. These may be used
151      * to provide the user with a spoken description of what auto-correction
152      * will occur when a key is typed.
153      *
154      * @param suggestedWords the list of suggested auto-correction words
155      */
setAutoCorrection(final SuggestedWords suggestedWords)156     public void setAutoCorrection(final SuggestedWords suggestedWords) {
157         if (suggestedWords.mWillAutoCorrect) {
158             mAutoCorrectionWord = suggestedWords.getWord(SuggestedWords.INDEX_OF_AUTO_CORRECTION);
159             final SuggestedWords.SuggestedWordInfo typedWordInfo = suggestedWords.mTypedWordInfo;
160             if (null == typedWordInfo) {
161                 mTypedWord = null;
162             } else {
163                 mTypedWord = typedWordInfo.mWord;
164             }
165         } else {
166             mAutoCorrectionWord = null;
167             mTypedWord = null;
168         }
169     }
170 
171     /**
172      * Obtains a description for an auto-correction key, taking into account the
173      * currently typed word and auto-correction.
174      *
175      * @param keyCodeDescription spoken description of the key that will insert
176      *            an auto-correction
177      * @param shouldObscure whether the key should be obscured
178      * @return a description including a description of the auto-correction, if
179      *         needed
180      */
getAutoCorrectionDescription( final String keyCodeDescription, final boolean shouldObscure)181     public String getAutoCorrectionDescription(
182             final String keyCodeDescription, final boolean shouldObscure) {
183         if (!TextUtils.isEmpty(mAutoCorrectionWord)) {
184             if (!TextUtils.equals(mAutoCorrectionWord, mTypedWord)) {
185                 if (shouldObscure) {
186                     // This should never happen, but just in case...
187                     return mContext.getString(R.string.spoken_auto_correct_obscured,
188                             keyCodeDescription);
189                 }
190                 return mContext.getString(R.string.spoken_auto_correct, keyCodeDescription,
191                         mTypedWord, mAutoCorrectionWord);
192             }
193         }
194 
195         return keyCodeDescription;
196     }
197 
198     /**
199      * Sends the specified text to the {@link AccessibilityManager} to be
200      * spoken.
201      *
202      * @param view The source view.
203      * @param text The text to speak.
204      */
announceForAccessibility(final View view, final CharSequence text)205     public void announceForAccessibility(final View view, final CharSequence text) {
206         if (!mAccessibilityManager.isEnabled()) {
207             Log.e(TAG, "Attempted to speak when accessibility was disabled!");
208             return;
209         }
210 
211         // The following is a hack to avoid using the heavy-weight TextToSpeech
212         // class. Instead, we're just forcing a fake AccessibilityEvent into
213         // the screen reader to make it speak.
214         final AccessibilityEvent event = AccessibilityEvent.obtain();
215 
216         event.setPackageName(PACKAGE);
217         event.setClassName(CLASS);
218         event.setEventTime(SystemClock.uptimeMillis());
219         event.setEnabled(true);
220         event.getText().add(text);
221 
222         // Platforms starting at SDK version 16 (Build.VERSION_CODES.JELLY_BEAN) should use
223         // announce events.
224         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
225             event.setEventType(AccessibilityEventCompat.TYPE_ANNOUNCEMENT);
226         } else {
227             event.setEventType(AccessibilityEvent.TYPE_VIEW_FOCUSED);
228         }
229 
230         final ViewParent viewParent = view.getParent();
231         if ((viewParent == null) || !(viewParent instanceof ViewGroup)) {
232             Log.e(TAG, "Failed to obtain ViewParent in announceForAccessibility");
233             return;
234         }
235 
236         viewParent.requestSendAccessibilityEvent(view, event);
237     }
238 
239     /**
240      * Handles speaking the "connect a headset to hear passwords" notification
241      * when connecting to a password field.
242      *
243      * @param view The source view.
244      * @param editorInfo The input connection's editor info attribute.
245      * @param restarting Whether the connection is being restarted.
246      */
onStartInputViewInternal(final View view, final EditorInfo editorInfo, final boolean restarting)247     public void onStartInputViewInternal(final View view, final EditorInfo editorInfo,
248             final boolean restarting) {
249         if (shouldObscureInput(editorInfo)) {
250             final CharSequence text = mContext.getText(R.string.spoken_use_headphones);
251             announceForAccessibility(view, text);
252         }
253     }
254 
255     /**
256      * Sends the specified {@link AccessibilityEvent} if accessibility is
257      * enabled. No operation if accessibility is disabled.
258      *
259      * @param event The event to send.
260      */
requestSendAccessibilityEvent(final AccessibilityEvent event)261     public void requestSendAccessibilityEvent(final AccessibilityEvent event) {
262         if (mAccessibilityManager.isEnabled()) {
263             mAccessibilityManager.sendAccessibilityEvent(event);
264         }
265     }
266 }
267