Java tutorial
/* * Copyright (C) 2011 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.android.inputmethod.accessibility; import android.content.Context; import android.media.AudioManager; import android.os.Build; import android.os.SystemClock; import android.provider.Settings; import android.support.v4.view.accessibility.AccessibilityEventCompat; import android.text.TextUtils; import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.ViewParent; import android.view.accessibility.AccessibilityEvent; import android.view.accessibility.AccessibilityManager; import android.view.inputmethod.EditorInfo; import com.android.inputmethod.compat.SettingsSecureCompatUtils; import com.android.inputmethod.latin.R; import com.android.inputmethod.latin.SuggestedWords; import com.android.inputmethod.latin.utils.InputTypeUtils; public final class AccessibilityUtils { private static final String TAG = AccessibilityUtils.class.getSimpleName(); private static final String CLASS = AccessibilityUtils.class.getClass().getName(); private static final String PACKAGE = AccessibilityUtils.class.getClass().getPackage().getName(); private static final AccessibilityUtils sInstance = new AccessibilityUtils(); private Context mContext; private AccessibilityManager mAccessibilityManager; private AudioManager mAudioManager; /** The most recent auto-correction. */ private String mAutoCorrectionWord; /** The most recent typed word for auto-correction. */ private String mTypedWord; /* * Setting this constant to {@code false} will disable all keyboard * accessibility code, regardless of whether Accessibility is turned on in * the system settings. It should ONLY be used in the event of an emergency. */ private static final boolean ENABLE_ACCESSIBILITY = true; public static void init(final Context context) { if (!ENABLE_ACCESSIBILITY) return; // These only need to be initialized if the kill switch is off. sInstance.initInternal(context); } public static AccessibilityUtils getInstance() { return sInstance; } private AccessibilityUtils() { // This class is not publicly instantiable. } private void initInternal(final Context context) { mContext = context; mAccessibilityManager = (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE); mAudioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE); } /** * Returns {@code true} if accessibility is enabled. Currently, this means * that the kill switch is off and system accessibility is turned on. * * @return {@code true} if accessibility is enabled. */ public boolean isAccessibilityEnabled() { return ENABLE_ACCESSIBILITY && mAccessibilityManager.isEnabled(); } /** * Returns {@code true} if touch exploration is enabled. Currently, this * means that the kill switch is off, the device supports touch exploration, * and system accessibility is turned on. * * @return {@code true} if touch exploration is enabled. */ public boolean isTouchExplorationEnabled() { return isAccessibilityEnabled() && mAccessibilityManager.isTouchExplorationEnabled(); } /** * Returns {@true} if the provided event is a touch exploration (e.g. hover) * event. This is used to determine whether the event should be processed by * the touch exploration code within the keyboard. * * @param event The event to check. * @return {@true} is the event is a touch exploration event */ public static boolean isTouchExplorationEvent(final MotionEvent event) { final int action = event.getAction(); return action == MotionEvent.ACTION_HOVER_ENTER || action == MotionEvent.ACTION_HOVER_EXIT || action == MotionEvent.ACTION_HOVER_MOVE; } /** * Returns whether the device should obscure typed password characters. * Typically this means speaking "dot" in place of non-control characters. * * @return {@code true} if the device should obscure password characters. */ @SuppressWarnings("deprecation") public boolean shouldObscureInput(final EditorInfo editorInfo) { if (editorInfo == null) return false; // The user can optionally force speaking passwords. if (SettingsSecureCompatUtils.ACCESSIBILITY_SPEAK_PASSWORD != null) { final boolean speakPassword = Settings.Secure.getInt(mContext.getContentResolver(), SettingsSecureCompatUtils.ACCESSIBILITY_SPEAK_PASSWORD, 0) != 0; if (speakPassword) return false; } // Always speak if the user is listening through headphones. if (mAudioManager.isWiredHeadsetOn() || mAudioManager.isBluetoothA2dpOn()) { return false; } // Don't speak if the IME is connected to a password field. return InputTypeUtils.isPasswordInputType(editorInfo.inputType); } /** * Sets the current auto-correction word and typed word. These may be used * to provide the user with a spoken description of what auto-correction * will occur when a key is typed. * * @param suggestedWords the list of suggested auto-correction words */ public void setAutoCorrection(final SuggestedWords suggestedWords) { if (suggestedWords.mWillAutoCorrect) { mAutoCorrectionWord = suggestedWords.getWord(SuggestedWords.INDEX_OF_AUTO_CORRECTION); final SuggestedWords.SuggestedWordInfo typedWordInfo = suggestedWords.mTypedWordInfo; if (null == typedWordInfo) { mTypedWord = null; } else { mTypedWord = typedWordInfo.mWord; } } else { mAutoCorrectionWord = null; mTypedWord = null; } } /** * Obtains a description for an auto-correction key, taking into account the * currently typed word and auto-correction. * * @param keyCodeDescription spoken description of the key that will insert * an auto-correction * @param shouldObscure whether the key should be obscured * @return a description including a description of the auto-correction, if * needed */ public String getAutoCorrectionDescription(final String keyCodeDescription, final boolean shouldObscure) { if (!TextUtils.isEmpty(mAutoCorrectionWord)) { if (!TextUtils.equals(mAutoCorrectionWord, mTypedWord)) { if (shouldObscure) { // This should never happen, but just in case... return mContext.getString(R.string.spoken_auto_correct_obscured, keyCodeDescription); } return mContext.getString(R.string.spoken_auto_correct, keyCodeDescription, mTypedWord, mAutoCorrectionWord); } } return keyCodeDescription; } /** * Sends the specified text to the {@link AccessibilityManager} to be * spoken. * * @param view The source view. * @param text The text to speak. */ public void announceForAccessibility(final View view, final CharSequence text) { if (!mAccessibilityManager.isEnabled()) { Log.e(TAG, "Attempted to speak when accessibility was disabled!"); return; } // The following is a hack to avoid using the heavy-weight TextToSpeech // class. Instead, we're just forcing a fake AccessibilityEvent into // the screen reader to make it speak. final AccessibilityEvent event = AccessibilityEvent.obtain(); event.setPackageName(PACKAGE); event.setClassName(CLASS); event.setEventTime(SystemClock.uptimeMillis()); event.setEnabled(true); event.getText().add(text); // Platforms starting at SDK version 16 (Build.VERSION_CODES.JELLY_BEAN) should use // announce events. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) { event.setEventType(AccessibilityEventCompat.TYPE_ANNOUNCEMENT); } else { event.setEventType(AccessibilityEvent.TYPE_VIEW_FOCUSED); } final ViewParent viewParent = view.getParent(); if ((viewParent == null) || !(viewParent instanceof ViewGroup)) { Log.e(TAG, "Failed to obtain ViewParent in announceForAccessibility"); return; } viewParent.requestSendAccessibilityEvent(view, event); } /** * Handles speaking the "connect a headset to hear passwords" notification * when connecting to a password field. * * @param view The source view. * @param editorInfo The input connection's editor info attribute. * @param restarting Whether the connection is being restarted. */ public void onStartInputViewInternal(final View view, final EditorInfo editorInfo, final boolean restarting) { if (shouldObscureInput(editorInfo)) { final CharSequence text = mContext.getText(R.string.spoken_use_headphones); announceForAccessibility(view, text); } } /** * Sends the specified {@link AccessibilityEvent} if accessibility is * enabled. No operation if accessibility is disabled. * * @param event The event to send. */ public void requestSendAccessibilityEvent(final AccessibilityEvent event) { if (mAccessibilityManager.isEnabled()) { mAccessibilityManager.sendAccessibilityEvent(event); } } }