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
17package com.android.inputmethod.accessibility;
18
19import android.content.Context;
20import android.media.AudioManager;
21import android.os.Build;
22import android.os.SystemClock;
23import android.provider.Settings;
24import android.support.v4.view.accessibility.AccessibilityEventCompat;
25import android.text.TextUtils;
26import android.util.Log;
27import android.view.MotionEvent;
28import android.view.View;
29import android.view.ViewGroup;
30import android.view.ViewParent;
31import android.view.accessibility.AccessibilityEvent;
32import android.view.accessibility.AccessibilityManager;
33import android.view.inputmethod.EditorInfo;
34
35import com.android.inputmethod.compat.SettingsSecureCompatUtils;
36import com.android.inputmethod.latin.R;
37import com.android.inputmethod.latin.SuggestedWords;
38import com.android.inputmethod.latin.utils.InputTypeUtils;
39
40public 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
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
72    public static AccessibilityUtils getInstance() {
73        return sInstance;
74    }
75
76    private AccessibilityUtils() {
77        // This class is not publicly instantiable.
78    }
79
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     */
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     */
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     */
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")
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     */
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     */
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     */
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     */
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     */
261    public void requestSendAccessibilityEvent(final AccessibilityEvent event) {
262        if (mAccessibilityManager.isEnabled()) {
263            mAccessibilityManager.sendAccessibilityEvent(event);
264        }
265    }
266}
267