Refactor accessibility classes to be more generic

Change-Id: Ifad1905f304bccdc39f0d5fbcab8a6353e0b4f76

1 files changed, 305 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/accessibility/KeyboardAccessibilityNodeProvider.java b/java/src/com/android/inputmethod/accessibility/KeyboardAccessibilityNodeProvider.java
new file mode 100644
index 000000000..cddd1c7ed
--- /dev/null
+++ b/java/src/com/android/inputmethod/accessibility/KeyboardAccessibilityNodeProvider.java
@@ -0,0 +1,305 @@
+/*
+ * Copyright (C) 2012 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.graphics.Rect;
+import android.os.Bundle;
+import android.support.v4.view.ViewCompat;
+import android.support.v4.view.accessibility.AccessibilityEventCompat;
+import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
+import android.support.v4.view.accessibility.AccessibilityNodeProviderCompat;
+import android.support.v4.view.accessibility.AccessibilityRecordCompat;
+import android.util.Log;
+import android.view.View;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.inputmethod.EditorInfo;
+
+import com.android.inputmethod.keyboard.Key;
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.KeyboardView;
+import com.android.inputmethod.latin.settings.Settings;
+import com.android.inputmethod.latin.settings.SettingsValues;
+import com.android.inputmethod.latin.utils.CoordinateUtils;
+
+import java.util.List;
+
+/**
+ * Exposes a virtual view sub-tree for {@link KeyboardView} and generates
+ * {@link AccessibilityEvent}s for individual {@link Key}s.
+ * <p>
+ * A virtual sub-tree is composed of imaginary {@link View}s that are reported
+ * as a part of the view hierarchy for accessibility purposes. This enables
+ * custom views that draw complex content to report them selves as a tree of
+ * virtual views, thus conveying their logical structure.
+ * </p>
+ */
+public final class KeyboardAccessibilityNodeProvider extends AccessibilityNodeProviderCompat {
+    private static final String TAG = KeyboardAccessibilityNodeProvider.class.getSimpleName();
+    private static final int UNDEFINED = Integer.MIN_VALUE;
+
+    private final KeyCodeDescriptionMapper mKeyCodeDescriptionMapper;
+    private final AccessibilityUtils mAccessibilityUtils;
+
+    /** Temporary rect used to calculate in-screen bounds. */
+    private final Rect mTempBoundsInScreen = new Rect();
+
+    /** The parent view's cached on-screen location. */
+    private final int[] mParentLocation = CoordinateUtils.newInstance();
+
+    /** The virtual view identifier for the focused node. */
+    private int mAccessibilityFocusedView = UNDEFINED;
+
+    /** The current keyboard view. */
+    private final KeyboardView mKeyboardView;
+
+    /** The current keyboard. */
+    private Keyboard mKeyboard;
+
+    public KeyboardAccessibilityNodeProvider(final KeyboardView keyboardView) {
+        super();
+        mKeyCodeDescriptionMapper = KeyCodeDescriptionMapper.getInstance();
+        mAccessibilityUtils = AccessibilityUtils.getInstance();
+        mKeyboardView = keyboardView;
+        updateParentLocation();
+
+        // Since this class is constructed lazily, we might not get a subsequent
+        // call to setKeyboard() and therefore need to call it now.
+        setKeyboard(keyboardView.getKeyboard());
+    }
+
+    /**
+     * Sets the keyboard represented by this node provider.
+     *
+     * @param keyboard The keyboard that is being set to the keyboard view.
+     */
+    public void setKeyboard(final Keyboard keyboard) {
+        mKeyboard = keyboard;
+    }
+
+    private Key getKeyOf(final int virtualViewId) {
+        if (mKeyboard == null) {
+            return null;
+        }
+        final List<Key> sortedKeys = mKeyboard.getSortedKeys();
+        // Use a virtual view id as an index of the sorted keys list.
+        if (virtualViewId >= 0 && virtualViewId < sortedKeys.size()) {
+            return sortedKeys.get(virtualViewId);
+        }
+        return null;
+    }
+
+    private int getVirtualViewIdOf(final Key key) {
+        if (mKeyboard == null) {
+            return View.NO_ID;
+        }
+        final List<Key> sortedKeys = mKeyboard.getSortedKeys();
+        final int size = sortedKeys.size();
+        for (int index = 0; index < size; index++) {
+            if (sortedKeys.get(index) == key) {
+                // Use an index of the sorted keys list as a virtual view id.
+                return index;
+            }
+        }
+        return View.NO_ID;
+    }
+
+    /**
+     * Creates and populates an {@link AccessibilityEvent} for the specified key
+     * and event type.
+     *
+     * @param key A key on the host keyboard view.
+     * @param eventType The event type to create.
+     * @return A populated {@link AccessibilityEvent} for the key.
+     * @see AccessibilityEvent
+     */
+    public AccessibilityEvent createAccessibilityEvent(final Key key, final int eventType) {
+        final int virtualViewId = getVirtualViewIdOf(key);
+        final String keyDescription = getKeyDescription(key);
+        final AccessibilityEvent event = AccessibilityEvent.obtain(eventType);
+        event.setPackageName(mKeyboardView.getContext().getPackageName());
+        event.setClassName(key.getClass().getName());
+        event.setContentDescription(keyDescription);
+        event.setEnabled(true);
+        final AccessibilityRecordCompat record = new AccessibilityRecordCompat(event);
+        record.setSource(mKeyboardView, virtualViewId);
+        return event;
+    }
+
+    /**
+     * Returns an {@link AccessibilityNodeInfoCompat} representing a virtual
+     * view, i.e. a descendant of the host View, with the given <code>virtualViewId</code> or
+     * the host View itself if <code>virtualViewId</code> equals to {@link View#NO_ID}.
+     * <p>
+     * A virtual descendant is an imaginary View that is reported as a part of
+     * the view hierarchy for accessibility purposes. This enables custom views
+     * that draw complex content to report them selves as a tree of virtual
+     * views, thus conveying their logical structure.
+     * </p>
+     * <p>
+     * The implementer is responsible for obtaining an accessibility node info
+     * from the pool of reusable instances and setting the desired properties of
+     * the node info before returning it.
+     * </p>
+     *
+     * @param virtualViewId A client defined virtual view id.
+     * @return A populated {@link AccessibilityNodeInfoCompat} for a virtual descendant or the host
+     * View.
+     * @see AccessibilityNodeInfoCompat
+     */
+    @Override
+    public AccessibilityNodeInfoCompat createAccessibilityNodeInfo(final int virtualViewId) {
+        if (virtualViewId == UNDEFINED) {
+            return null;
+        }
+        if (virtualViewId == View.NO_ID) {
+            // We are requested to create an AccessibilityNodeInfo describing
+            // this View, i.e. the root of the virtual sub-tree.
+            final AccessibilityNodeInfoCompat rootInfo =
+                    AccessibilityNodeInfoCompat.obtain(mKeyboardView);
+            ViewCompat.onInitializeAccessibilityNodeInfo(mKeyboardView, rootInfo);
+
+            // Add the virtual children of the root View.
+            final List<Key> sortedKeys = mKeyboard.getSortedKeys();
+            final int size = sortedKeys.size();
+            for (int index = 0; index < size; index++) {
+                final Key key = sortedKeys.get(index);
+                if (key.isSpacer()) {
+                    continue;
+                }
+                // Use an index of the sorted keys list as a virtual view id.
+                rootInfo.addChild(mKeyboardView, index);
+            }
+            return rootInfo;
+        }
+
+        // Find the key that corresponds to the given virtual view id.
+        final Key key = getKeyOf(virtualViewId);
+        if (key == null) {
+            Log.e(TAG, "Invalid virtual view ID: " + virtualViewId);
+            return null;
+        }
+        final String keyDescription = getKeyDescription(key);
+        final Rect boundsInParent = key.getHitBox();
+
+        // Calculate the key's in-screen bounds.
+        mTempBoundsInScreen.set(boundsInParent);
+        mTempBoundsInScreen.offset(
+                CoordinateUtils.x(mParentLocation), CoordinateUtils.y(mParentLocation));
+        final Rect boundsInScreen = mTempBoundsInScreen;
+
+        // Obtain and initialize an AccessibilityNodeInfo with information about the virtual view.
+        final AccessibilityNodeInfoCompat info = AccessibilityNodeInfoCompat.obtain();
+        info.setPackageName(mKeyboardView.getContext().getPackageName());
+        info.setClassName(key.getClass().getName());
+        info.setContentDescription(keyDescription);
+        info.setBoundsInParent(boundsInParent);
+        info.setBoundsInScreen(boundsInScreen);
+        info.setParent(mKeyboardView);
+        info.setSource(mKeyboardView, virtualViewId);
+        info.setBoundsInScreen(boundsInScreen);
+        info.setEnabled(true);
+        info.setVisibleToUser(true);
+
+        if (mAccessibilityFocusedView == virtualViewId) {
+            info.addAction(AccessibilityNodeInfoCompat.ACTION_CLEAR_ACCESSIBILITY_FOCUS);
+        } else {
+            info.addAction(AccessibilityNodeInfoCompat.ACTION_ACCESSIBILITY_FOCUS);
+        }
+        return info;
+    }
+
+    @Override
+    public boolean performAction(final int virtualViewId, final int action,
+            final Bundle arguments) {
+        final Key key = getKeyOf(virtualViewId);
+        if (key == null) {
+            return false;
+        }
+        return performActionForKey(key, action, arguments);
+    }
+
+    /**
+     * Performs the specified accessibility action for the given key.
+     *
+     * @param key The on which to perform the action.
+     * @param action The action to perform.
+     * @param arguments The action's arguments.
+     * @return The result of performing the action, or false if the action is not supported.
+     */
+    boolean performActionForKey(final Key key, final int action, final Bundle arguments) {
+        final int virtualViewId = getVirtualViewIdOf(key);
+
+        switch (action) {
+        case AccessibilityNodeInfoCompat.ACTION_ACCESSIBILITY_FOCUS:
+            if (mAccessibilityFocusedView == virtualViewId) {
+                return false;
+            }
+            mAccessibilityFocusedView = virtualViewId;
+            sendAccessibilityEventForKey(
+                    key, AccessibilityEventCompat.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+            return true;
+        case AccessibilityNodeInfoCompat.ACTION_CLEAR_ACCESSIBILITY_FOCUS:
+            if (mAccessibilityFocusedView != virtualViewId) {
+                return false;
+            }
+            mAccessibilityFocusedView = UNDEFINED;
+            sendAccessibilityEventForKey(
+                    key, AccessibilityEventCompat.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
+            return true;
+        default:
+            return false;
+        }
+    }
+
+    /**
+     * Sends an accessibility event for the given {@link Key}.
+     *
+     * @param key The key that's sending the event.
+     * @param eventType The type of event to send.
+     */
+    void sendAccessibilityEventForKey(final Key key, final int eventType) {
+        final AccessibilityEvent event = createAccessibilityEvent(key, eventType);
+        mAccessibilityUtils.requestSendAccessibilityEvent(event);
+    }
+
+    /**
+     * Returns the context-specific description for a {@link Key}.
+     *
+     * @param key The key to describe.
+     * @return The context-specific description of the key.
+     */
+    private String getKeyDescription(final Key key) {
+        final EditorInfo editorInfo = mKeyboard.mId.mEditorInfo;
+        final boolean shouldObscure = mAccessibilityUtils.shouldObscureInput(editorInfo);
+        final SettingsValues currentSettings = Settings.getInstance().getCurrent();
+        final String keyCodeDescription = mKeyCodeDescriptionMapper.getDescriptionForKey(
+                mKeyboardView.getContext(), mKeyboard, key, shouldObscure);
+        if (currentSettings.isWordSeparator(key.getCode())) {
+            return mAccessibilityUtils.getAutoCorrectionDescription(
+                    keyCodeDescription, shouldObscure);
+        } else {
+            return keyCodeDescription;
+        }
+    }
+
+    /**
+     * Updates the parent's on-screen location.
+     */
+    private void updateParentLocation() {
+        mKeyboardView.getLocationOnScreen(mParentLocation);
+    }
+}