/*
* 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.os.SystemClock;
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.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;
public class KeyboardAccessibilityDelegate<KV extends KeyboardView>
extends AccessibilityDelegateCompat {
protected final KV mKeyboardView;
protected final KeyDetector mKeyDetector;
private Keyboard mKeyboard;
private KeyboardAccessibilityNodeProvider mAccessibilityNodeProvider;
private Key mLastHoverKey;
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 Keyboard getKeyboard() {
return mKeyboard;
}
/**
* 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;
}
/**
* 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 dispatchHoverEvent(final MotionEvent event) {
final int x = (int) event.getX();
final int y = (int) event.getY();
final Key previousKey = mLastHoverKey;
final Key key = mKeyDetector.detectHitKey(x, y);
mLastHoverKey = key;
switch (event.getAction()) {
case MotionEvent.ACTION_HOVER_EXIT:
// 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) {
final long downTime = simulateKeyPress(key);
simulateKeyRelease(key, downTime);
}
//$FALL-THROUGH$
case MotionEvent.ACTION_HOVER_ENTER:
return onHoverKey(key, event);
case MotionEvent.ACTION_HOVER_MOVE:
if (key != previousKey) {
return onTransitionKey(key, previousKey, event);
}
return onHoverKey(key, event);
}
return false;
}
/**
* Simulates a key press by injecting touch an event into the keyboard view.
* This avoids the complexity of trackers and listeners within the keyboard.
*
* @param key The key to press.
*/
private long simulateKeyPress(final Key key) {
final int x = key.getHitBox().centerX();
final int y = key.getHitBox().centerY();
final long downTime = SystemClock.uptimeMillis();
final MotionEvent downEvent = MotionEvent.obtain(
downTime, downTime, MotionEvent.ACTION_DOWN, x, y, 0);
mKeyboardView.onTouchEvent(downEvent);
downEvent.recycle();
return downTime;
}
/**
* Simulates a key release by injecting touch an event into the keyboard view.
* This avoids the complexity of trackers and listeners within the keyboard.
*
* @param key The key to release.
*/
private void simulateKeyRelease(final Key key, final long downTime) {
final int x = key.getHitBox().centerX();
final int y = key.getHitBox().centerY();
final MotionEvent upEvent = MotionEvent.obtain(
downTime, SystemClock.uptimeMillis(), MotionEvent.ACTION_UP, x, y, 0);
mKeyboardView.onTouchEvent(upEvent);
upEvent.recycle();
}
/**
* Simulates a transition between two {@link Key}s by sending a HOVER_EXIT on the previous key,
* a HOVER_ENTER on the current key, and a HOVER_MOVE on the current key.
*
* @param currentKey The currently hovered key.
* @param previousKey The previously hovered key.
* @param event The event that triggered the transition.
* @return {@code true} if the event was handled.
*/
private boolean onTransitionKey(final Key currentKey, final Key previousKey,
final MotionEvent event) {
final int savedAction = event.getAction();
event.setAction(MotionEvent.ACTION_HOVER_EXIT);
onHoverKey(previousKey, event);
event.setAction(MotionEvent.ACTION_HOVER_ENTER);
onHoverKey(currentKey, event);
event.setAction(MotionEvent.ACTION_HOVER_MOVE);
final boolean handled = onHoverKey(currentKey, event);
event.setAction(savedAction);
return handled;
}
/**
* Handles a hover event on a key. If {@link Key} extended View, this would be analogous to
* calling View.onHoverEvent(MotionEvent).
*
* @param key The currently hovered key.
* @param event The hover event.
* @return {@code true} if the event was handled.
*/
private boolean onHoverKey(final Key key, final MotionEvent event) {
// Null keys can't receive events.
if (key == null) {
return false;
}
final KeyboardAccessibilityNodeProvider provider = getAccessibilityNodeProvider();
switch (event.getAction()) {
case MotionEvent.ACTION_HOVER_ENTER:
provider.sendAccessibilityEventForKey(
key, AccessibilityEventCompat.TYPE_VIEW_HOVER_ENTER);
provider.performActionForKey(
key, AccessibilityNodeInfoCompat.ACTION_ACCESSIBILITY_FOCUS);
break;
case MotionEvent.ACTION_HOVER_EXIT:
provider.sendAccessibilityEventForKey(
key, AccessibilityEventCompat.TYPE_VIEW_HOVER_EXIT);
break;
}
return true;
}
}