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diff --git a/java/src/com/android/inputmethod/accessibility/KeyboardAccessibilityDelegate.java b/java/src/com/android/inputmethod/accessibility/KeyboardAccessibilityDelegate.java
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+++ b/java/src/com/android/inputmethod/accessibility/KeyboardAccessibilityDelegate.java
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+/*
+ * 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.support.v4.view.AccessibilityDelegateCompat;
+import android.support.v4.view.ViewCompat;
+import android.support.v4.view.accessibility.AccessibilityEventCompat;
+import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
+import android.util.Log;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.ViewParent;
+import android.view.accessibility.AccessibilityEvent;
+
+import com.android.inputmethod.keyboard.Key;
+import com.android.inputmethod.keyboard.KeyDetector;
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.KeyboardView;
+import com.android.inputmethod.keyboard.PointerTracker;
+
+/**
+ * This class represents a delegate that can be registered in a class that extends
+ * {@link KeyboardView} to enhance accessibility support via composition rather via inheritance.
+ *
+ * To implement accessibility mode, the target keyboard view has to:<p>
+ * - Call {@link #setKeyboard(Keyboard)} when a new keyboard is set to the keyboard view.
+ * - Dispatch a hover event by calling {@link #onHoverEnter(MotionEvent)}.
+ *
+ * @param <KV> The keyboard view class type.
+ */
+public class KeyboardAccessibilityDelegate<KV extends KeyboardView>
+        extends AccessibilityDelegateCompat {
+    private static final String TAG = KeyboardAccessibilityDelegate.class.getSimpleName();
+    protected static final boolean DEBUG_HOVER = false;
+
+    protected final KV mKeyboardView;
+    protected final KeyDetector mKeyDetector;
+    private Keyboard mKeyboard;
+    private KeyboardAccessibilityNodeProvider mAccessibilityNodeProvider;
+    private Key mLastHoverKey;
+
+    public static final int HOVER_EVENT_POINTER_ID = 0;
+
+    public KeyboardAccessibilityDelegate(final KV keyboardView, final KeyDetector keyDetector) {
+        super();
+        mKeyboardView = keyboardView;
+        mKeyDetector = keyDetector;
+
+        // Ensure that the view has an accessibility delegate.
+        ViewCompat.setAccessibilityDelegate(keyboardView, this);
+    }
+
+    /**
+     * Called when the keyboard layout changes.
+     * <p>
+     * <b>Note:</b> This method will be called even if accessibility is not
+     * enabled.
+     * @param keyboard The keyboard that is being set to the wrapping view.
+     */
+    public void setKeyboard(final Keyboard keyboard) {
+        if (keyboard == null) {
+            return;
+        }
+        if (mAccessibilityNodeProvider != null) {
+            mAccessibilityNodeProvider.setKeyboard(keyboard);
+        }
+        mKeyboard = keyboard;
+    }
+
+    protected final Keyboard getKeyboard() {
+        return mKeyboard;
+    }
+
+    protected final void setLastHoverKey(final Key key) {
+        mLastHoverKey = key;
+    }
+
+    protected final Key getLastHoverKey() {
+        return mLastHoverKey;
+    }
+
+    /**
+     * Sends a window state change event with the specified string resource id.
+     *
+     * @param resId The string resource id of the text to send with the event.
+     */
+    protected void sendWindowStateChanged(final int resId) {
+        if (resId == 0) {
+            return;
+        }
+        final Context context = mKeyboardView.getContext();
+        sendWindowStateChanged(context.getString(resId));
+    }
+
+    /**
+     * Sends a window state change event with the specified text.
+     *
+     * @param text The text to send with the event.
+     */
+    protected void sendWindowStateChanged(final String text) {
+        final AccessibilityEvent stateChange = AccessibilityEvent.obtain(
+                AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED);
+        mKeyboardView.onInitializeAccessibilityEvent(stateChange);
+        stateChange.getText().add(text);
+        stateChange.setContentDescription(null);
+
+        final ViewParent parent = mKeyboardView.getParent();
+        if (parent != null) {
+            parent.requestSendAccessibilityEvent(mKeyboardView, stateChange);
+        }
+    }
+
+    /**
+     * Delegate method for View.getAccessibilityNodeProvider(). This method is called in SDK
+     * version 15 (Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) and higher to obtain the virtual
+     * node hierarchy provider.
+     *
+     * @param host The host view for the provider.
+     * @return The accessibility node provider for the current keyboard.
+     */
+    @Override
+    public KeyboardAccessibilityNodeProvider getAccessibilityNodeProvider(final View host) {
+        return getAccessibilityNodeProvider();
+    }
+
+    /**
+     * @return A lazily-instantiated node provider for this view delegate.
+     */
+    protected KeyboardAccessibilityNodeProvider getAccessibilityNodeProvider() {
+        // Instantiate the provide only when requested. Since the system
+        // will call this method multiple times it is a good practice to
+        // cache the provider instance.
+        if (mAccessibilityNodeProvider == null) {
+            mAccessibilityNodeProvider = new KeyboardAccessibilityNodeProvider(mKeyboardView);
+        }
+        return mAccessibilityNodeProvider;
+    }
+
+    /**
+     * Get a key that a hover event is on.
+     *
+     * @param event The hover event.
+     * @return key The key that the <code>event</code> is on.
+     */
+    protected final Key getHoverKeyOf(final MotionEvent event) {
+        final int actionIndex = event.getActionIndex();
+        final int x = (int)event.getX(actionIndex);
+        final int y = (int)event.getY(actionIndex);
+        return mKeyDetector.detectHitKey(x, y);
+    }
+
+    /**
+     * Receives hover events when touch exploration is turned on in SDK versions ICS and higher.
+     *
+     * @param event The hover event.
+     * @return {@code true} if the event is handled.
+     */
+    public boolean onHoverEvent(final MotionEvent event) {
+        switch (event.getActionMasked()) {
+        case MotionEvent.ACTION_HOVER_ENTER:
+            onHoverEnter(event);
+            break;
+        case MotionEvent.ACTION_HOVER_MOVE:
+            onHoverMove(event);
+            break;
+        case MotionEvent.ACTION_HOVER_EXIT:
+            onHoverExit(event);
+            break;
+        default:
+            Log.w(getClass().getSimpleName(), "Unknown hover event: " + event);
+            break;
+        }
+        return true;
+    }
+
+    /**
+     * Process {@link MotionEvent#ACTION_HOVER_ENTER} event.
+     *
+     * @param event A hover enter event.
+     */
+    protected void onHoverEnter(final MotionEvent event) {
+        final Key key = getHoverKeyOf(event);
+        if (DEBUG_HOVER) {
+            Log.d(TAG, "onHoverEnter: key=" + key);
+        }
+        if (key != null) {
+            onHoverEnterTo(key);
+        }
+        setLastHoverKey(key);
+    }
+
+    /**
+     * Process {@link MotionEvent#ACTION_HOVER_MOVE} event.
+     *
+     * @param event A hover move event.
+     */
+    protected void onHoverMove(final MotionEvent event) {
+        final Key lastKey = getLastHoverKey();
+        final Key key = getHoverKeyOf(event);
+        if (key != lastKey) {
+            if (lastKey != null) {
+                onHoverExitFrom(lastKey);
+            }
+            if (key != null) {
+                onHoverEnterTo(key);
+            }
+        }
+        if (key != null) {
+            onHoverMoveWithin(key);
+        }
+        setLastHoverKey(key);
+    }
+
+    /**
+     * Process {@link MotionEvent#ACTION_HOVER_EXIT} event.
+     *
+     * @param event A hover exit event.
+     */
+    protected void onHoverExit(final MotionEvent event) {
+        final Key lastKey = getLastHoverKey();
+        if (DEBUG_HOVER) {
+            Log.d(TAG, "onHoverExit: key=" + getHoverKeyOf(event) + " last=" + lastKey);
+        }
+        if (lastKey != null) {
+            onHoverExitFrom(lastKey);
+        }
+        final Key key = getHoverKeyOf(event);
+        // Make sure we're not getting an EXIT event because the user slid
+        // off the keyboard area, then force a key press.
+        if (key != null) {
+            onRegisterHoverKey(key, event);
+            onHoverExitFrom(key);
+        }
+        setLastHoverKey(null);
+    }
+
+    /**
+     * Register a key that is selected by a hover event
+     *
+     * @param key A key to be registered.
+     * @param event A hover exit event that triggers key registering.
+     */
+    protected void onRegisterHoverKey(final Key key, final MotionEvent event) {
+        if (DEBUG_HOVER) {
+            Log.d(TAG, "onRegisterHoverKey: key=" + key);
+        }
+        simulateTouchEvent(MotionEvent.ACTION_DOWN, event);
+        simulateTouchEvent(MotionEvent.ACTION_UP, event);
+    }
+
+    /**
+     * Simulating a touch event by injecting a synthesized touch event into {@link PointerTracker}.
+     *
+     * @param touchAction The action of the synthesizing touch event.
+     * @param hoverEvent The base hover event from that the touch event is synthesized.
+     */
+    protected void simulateTouchEvent(final int touchAction, final MotionEvent hoverEvent) {
+        final MotionEvent touchEvent = synthesizeTouchEvent(touchAction, hoverEvent);
+        final int actionIndex = touchEvent.getActionIndex();
+        final int pointerId = touchEvent.getPointerId(actionIndex);
+        final PointerTracker tracker = PointerTracker.getPointerTracker(pointerId);
+        tracker.processMotionEvent(touchEvent, mKeyDetector);
+        touchEvent.recycle();
+    }
+
+    /**
+     * Synthesize a touch event from a hover event.
+     *
+     * @param touchAction The action of the synthesizing touch event.
+     * @param hoverEvent The base hover event from that the touch event is synthesized.
+     * @return The synthesized touch event of <code>touchAction</code> that has pointer information
+     * of <code>event</code>.
+     */
+    protected static MotionEvent synthesizeTouchEvent(final int touchAction,
+            final MotionEvent hoverEvent) {
+        final MotionEvent touchEvent = MotionEvent.obtain(hoverEvent);
+        touchEvent.setAction(touchAction);
+        return touchEvent;
+    }
+
+    /**
+     * Handles a hover enter event on a key.
+     *
+     * @param key The currently hovered key.
+     */
+    protected void onHoverEnterTo(final Key key) {
+        if (DEBUG_HOVER) {
+            Log.d(TAG, "onHoverEnterTo: key=" + key);
+        }
+        key.onPressed();
+        mKeyboardView.invalidateKey(key);
+        final KeyboardAccessibilityNodeProvider provider = getAccessibilityNodeProvider();
+        provider.sendAccessibilityEventForKey(key, AccessibilityEventCompat.TYPE_VIEW_HOVER_ENTER);
+        provider.performActionForKey(key, AccessibilityNodeInfoCompat.ACTION_ACCESSIBILITY_FOCUS);
+    }
+
+    /**
+     * Handles a hover move event on a key.
+     *
+     * @param key The currently hovered key.
+     */
+    protected void onHoverMoveWithin(final Key key) { }
+
+    /**
+     * Handles a hover exit event on a key.
+     *
+     * @param key The currently hovered key.
+     */
+    protected void onHoverExitFrom(final Key key) {
+        if (DEBUG_HOVER) {
+            Log.d(TAG, "onHoverExitFrom: key=" + key);
+        }
+        key.onReleased();
+        mKeyboardView.invalidateKey(key);
+        final KeyboardAccessibilityNodeProvider provider = getAccessibilityNodeProvider();
+        provider.sendAccessibilityEventForKey(key, AccessibilityEventCompat.TYPE_VIEW_HOVER_EXIT);
+    }
+}