Added virtual view hierarchy for keyboard accessibility.

Bug: 5829051
Change-Id: Ied1b6267eec616bd3b9337f6e761b0c740aa0eb2

1 files changed, 377 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/accessibility/AccessibilityEntityProvider.java b/java/src/com/android/inputmethod/accessibility/AccessibilityEntityProvider.java
new file mode 100644
index 000000000..dc7c12ba6
--- /dev/null
+++ b/java/src/com/android/inputmethod/accessibility/AccessibilityEntityProvider.java
@@ -0,0 +1,377 @@
+/*
+ * 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.inputmethodservice.InputMethodService;
+import android.support.v4.view.ViewCompat;
+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.util.SparseArray;
+import android.view.View;
+import android.view.ViewTreeObserver.OnGlobalLayoutListener;
+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 java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * 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 class AccessibilityEntityProvider extends AccessibilityNodeProviderCompat {
+    private static final String TAG = AccessibilityEntityProvider.class.getSimpleName();
+
+    private final KeyboardView mKeyboardView;
+    private final InputMethodService mInputMethodService;
+    private final KeyCodeDescriptionMapper mKeyCodeDescriptionMapper;
+    private final AccessibilityUtils mAccessibilityUtils;
+
+    /** A map of integer IDs to {@link Key}s. */
+    private final SparseArray<Key> mVirtualViewIdToKey = new SparseArray<Key>();
+
+    /** 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 = new int[2];
+
+    public AccessibilityEntityProvider(KeyboardView keyboardView, InputMethodService inputMethod) {
+        mKeyboardView = keyboardView;
+        mInputMethodService = inputMethod;
+
+        mKeyCodeDescriptionMapper = KeyCodeDescriptionMapper.getInstance();
+        mAccessibilityUtils = AccessibilityUtils.getInstance();
+
+        assignVirtualViewIds();
+        updateParentLocation();
+
+        // Ensure that the on-screen bounds are cleared when the layout changes.
+        mKeyboardView.getViewTreeObserver().addOnGlobalLayoutListener(mGlobalLayoutListener);
+    }
+
+    /**
+     * 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(Key key, int eventType) {
+        final int virtualViewId = generateVirtualViewIdForKey(key);
+        final String keyDescription = getKeyDescription(key);
+
+        final AccessibilityEvent event = AccessibilityEvent.obtain(eventType);
+        event.setPackageName(mKeyboardView.getContext().getPackageName());
+        event.setClassName(key.getClass().getName());
+        event.getText().add(keyDescription);
+
+        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(int virtualViewId) {
+        AccessibilityNodeInfoCompat info = 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.
+            info = AccessibilityNodeInfoCompat.obtain(mKeyboardView);
+            ViewCompat.onInitializeAccessibilityNodeInfo(mKeyboardView, info);
+
+            // Add the virtual children of the root View.
+            // TODO(alanv): Need to assign a unique ID to each key.
+            final Keyboard keyboard = mKeyboardView.getKeyboard();
+            final Set<Key> keys = keyboard.mKeys;
+            for (Key key : keys) {
+                final int childVirtualViewId = generateVirtualViewIdForKey(key);
+                info.addChild(mKeyboardView, childVirtualViewId);
+            }
+        } else {
+            // Find the view that corresponds to the given id.
+            final Key key = mVirtualViewIdToKey.get(virtualViewId);
+            if (key == null) {
+                Log.e(TAG, "Invalid virtual view ID: " + virtualViewId);
+                return null;
+            }
+
+            final String keyDescription = getKeyDescription(key);
+            final Rect boundsInParent = key.mHitBox;
+
+            // Calculate the key's in-screen bounds.
+            mTempBoundsInScreen.set(boundsInParent);
+            mTempBoundsInScreen.offset(mParentLocation[0], mParentLocation[1]);
+
+            final Rect boundsInScreen = mTempBoundsInScreen;
+
+            // Obtain and initialize an AccessibilityNodeInfo with
+            // information about the virtual view.
+            info = AccessibilityNodeInfoCompat.obtain();
+            info.addAction(AccessibilityNodeInfoCompat.ACTION_SELECT);
+            info.addAction(AccessibilityNodeInfoCompat.ACTION_CLEAR_SELECTION);
+            info.setPackageName(mKeyboardView.getContext().getPackageName());
+            info.setClassName(key.getClass().getName());
+            info.setBoundsInParent(boundsInParent);
+            info.setBoundsInScreen(boundsInScreen);
+            info.setParent(mKeyboardView);
+            info.setSource(mKeyboardView, virtualViewId);
+            info.setBoundsInScreen(boundsInScreen);
+            info.setText(keyDescription);
+        }
+
+        return info;
+    }
+
+    /**
+     * Performs an accessibility action on 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}.
+     *
+     * @param action The action to perform.
+     * @param virtualViewId A client defined virtual view id.
+     * @return True if the action was performed.
+     * @see #createAccessibilityNodeInfo(int)
+     * @see AccessibilityNodeInfoCompat
+     */
+    @Override
+    public boolean performAccessibilityAction(int action, int virtualViewId) {
+        if (virtualViewId == View.NO_ID) {
+            // Perform the action on the host View.
+            switch (action) {
+            case AccessibilityNodeInfoCompat.ACTION_SELECT:
+                if (!mKeyboardView.isSelected()) {
+                    mKeyboardView.setSelected(true);
+                    return mKeyboardView.isSelected();
+                }
+                break;
+            case AccessibilityNodeInfoCompat.ACTION_CLEAR_SELECTION:
+                if (mKeyboardView.isSelected()) {
+                    mKeyboardView.setSelected(false);
+                    return !mKeyboardView.isSelected();
+                }
+                break;
+            }
+        } else {
+            // Find the view that corresponds to the given id.
+            final Key child = mVirtualViewIdToKey.get(virtualViewId);
+            if (child == null)
+                return false;
+
+            // Perform the action on a virtual view.
+            switch (action) {
+            case AccessibilityNodeInfoCompat.ACTION_SELECT:
+                // TODO: Provide some focus indicator.
+                return true;
+            case AccessibilityNodeInfoCompat.ACTION_CLEAR_SELECTION:
+                // TODO: Provide some clear focus indicator.
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Finds {@link AccessibilityNodeInfoCompat}s by text. The match is case
+     * insensitive containment. The search is relative to the virtual view, i.e.
+     * a descendant of the host View, with the given <code>virtualViewId</code> or the host
+     * View itself <code>virtualViewId</code> equals to {@link View#NO_ID}.
+     *
+     * @param virtualViewId A client defined virtual view id which defined the
+     *            root of the tree in which to perform the search.
+     * @param text The searched text.
+     * @return A list of node info.
+     * @see #createAccessibilityNodeInfo(int)
+     * @see AccessibilityNodeInfoCompat
+     */
+    @Override
+    public List<AccessibilityNodeInfoCompat> findAccessibilityNodeInfosByText(
+            String text, int virtualViewId) {
+        final String searchedLowerCase = text.toLowerCase();
+        final Keyboard keyboard = mKeyboardView.getKeyboard();
+
+        List<AccessibilityNodeInfoCompat> results = null;
+
+        if (virtualViewId == View.NO_ID) {
+            for (Key key : keyboard.mKeys) {
+                results = findByTextAndPopulate(searchedLowerCase, key, results);
+            }
+        } else {
+            final Key key = mVirtualViewIdToKey.get(virtualViewId);
+
+            results = findByTextAndPopulate(searchedLowerCase, key, results);
+        }
+
+        if (results == null) {
+            return Collections.emptyList();
+        }
+
+        return results;
+    }
+
+    /**
+     * Helper method for {@link #findAccessibilityNodeInfosByText(String, int)}.
+     * Takes a current set of results and matches a specified key against a
+     * lower-case search string. Returns an updated list of results.
+     *
+     * @param searchedLowerCase The lower-case search string.
+     * @param key The key to compare against.
+     * @param results The current list of results, or {@code null} if no results
+     *            found.
+     * @return An updated list of results, or {@code null} if no results found.
+     */
+    private List<AccessibilityNodeInfoCompat> findByTextAndPopulate(String searchedLowerCase,
+            Key key, List<AccessibilityNodeInfoCompat> results) {
+        if (!keyContainsText(key, searchedLowerCase)) {
+            return results;
+        }
+
+        final int childVirtualViewId = generateVirtualViewIdForKey(key);
+        final AccessibilityNodeInfoCompat nodeInfo = createAccessibilityNodeInfo(
+                childVirtualViewId);
+
+        if (results == null) {
+            results = new LinkedList<AccessibilityNodeInfoCompat>();
+        }
+
+        results.add(nodeInfo);
+
+        return results;
+    }
+
+    /**
+     * Returns whether a key's current description contains the lower-case
+     * search text.
+     *
+     * @param key The key to compare against.
+     * @param textLowerCase The lower-case search string.
+     * @return {@code true} if the key contains the search text.
+     */
+    private boolean keyContainsText(Key key, String textLowerCase) {
+        if (key == null) {
+            return false;
+        }
+
+        final String description = getKeyDescription(key);
+
+        if (description == null) {
+            return false;
+        }
+
+        return description.toLowerCase().contains(textLowerCase);
+    }
+
+    /**
+     * 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(Key key) {
+        final EditorInfo editorInfo = mInputMethodService.getCurrentInputEditorInfo();
+        final boolean shouldObscure = mAccessibilityUtils.shouldObscureInput(editorInfo);
+        final String keyDescription = mKeyCodeDescriptionMapper.getDescriptionForKey(
+                mKeyboardView.getContext(), mKeyboardView.getKeyboard(), key, shouldObscure);
+
+        return keyDescription;
+    }
+
+    /**
+     * Assigns virtual view IDs to keyboard keys and populates the related maps.
+     */
+    private void assignVirtualViewIds() {
+        final Keyboard keyboard = mKeyboardView.getKeyboard();
+        if (keyboard == null) {
+            return;
+        }
+
+        mVirtualViewIdToKey.clear();
+
+        final Set<Key> keySet = keyboard.mKeys;
+        for (Key key : keySet) {
+            final int virtualViewId = generateVirtualViewIdForKey(key);
+            mVirtualViewIdToKey.put(virtualViewId, key);
+        }
+    }
+
+    /**
+     * Updates the parent's on-screen location.
+     */
+    private void updateParentLocation() {
+        mKeyboardView.getLocationOnScreen(mParentLocation);
+    }
+
+    /**
+     * Generates a virtual view identifier for the specified key.
+     *
+     * @param key The key to identify.
+     * @return A virtual view identifier.
+     */
+    private static int generateVirtualViewIdForKey(Key key) {
+        // The key code is unique within an instance of a Keyboard.
+        return key.mCode;
+    }
+
+    private final OnGlobalLayoutListener mGlobalLayoutListener = new OnGlobalLayoutListener() {
+        @Override
+        public void onGlobalLayout() {
+            assignVirtualViewIds();
+            updateParentLocation();
+        }
+    };
+}