Added support for speaking keys through accessibility service.

Issue: 3366636

Change-Id: I70a2ebb4420782ba4d7d874ffc2259bb1b80446f

1 files changed, 211 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/AccessibilityUtils.java b/java/src/com/android/inputmethod/latin/AccessibilityUtils.java
new file mode 100644
index 000000000..cd3f9e0ad
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/AccessibilityUtils.java
@@ -0,0 +1,211 @@
+/*
+ * 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.latin;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.res.TypedArray;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityManager;
+
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.KeyboardSwitcher;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Utility functions for accessibility support.
+ */
+public class AccessibilityUtils {
+    /** Shared singleton instance. */
+    private static final AccessibilityUtils sInstance = new AccessibilityUtils();
+    private /* final */ LatinIME mService;
+    private /* final */ AccessibilityManager mAccessibilityManager;
+    private /* final */ Map<Integer, CharSequence> mDescriptions;
+
+    /**
+     * Returns a shared instance of AccessibilityUtils.
+     *
+     * @return A shared instance of AccessibilityUtils.
+     */
+    public static AccessibilityUtils getInstance() {
+        return sInstance;
+    }
+
+    /**
+     * Initializes (or re-initializes) the shared instance of AccessibilityUtils
+     * with the specified parent service and preferences.
+     *
+     * @param service The parent input method service.
+     * @param prefs The parent preferences.
+     */
+    public static void init(LatinIME service, SharedPreferences prefs) {
+        sInstance.initialize(service, prefs);
+    }
+
+    private AccessibilityUtils() {
+        // This class is not publicly instantiable.
+    }
+
+    /**
+     * Initializes (or re-initializes) with the specified parent service and
+     * preferences.
+     *
+     * @param service The parent input method service.
+     * @param prefs The parent preferences.
+     */
+    private void initialize(LatinIME service, SharedPreferences prefs) {
+        mService = service;
+        mAccessibilityManager = (AccessibilityManager) service.getSystemService(
+                Context.ACCESSIBILITY_SERVICE);
+        mDescriptions = null;
+    }
+
+    /**
+     * Returns true if accessibility is enabled.
+     *
+     * @return {@code true} if accessibility is enabled.
+     */
+    public boolean isAccessibilityEnabled() {
+        return mAccessibilityManager.isEnabled();
+    }
+
+    /**
+     * Speaks a key's action after it has been released. Does not speak letter
+     * keys since typed keys are already spoken aloud by TalkBack.
+     * <p>
+     * No-op if accessibility is not enabled.
+     * </p>
+     *
+     * @param primaryCode The primary code of the released key.
+     * @param switcher The input method's {@link KeyboardSwitcher}.
+     */
+    public void onRelease(int primaryCode, KeyboardSwitcher switcher) {
+        if (!isAccessibilityEnabled()) {
+            return;
+        }
+
+        int resId = -1;
+
+        switch (primaryCode) {
+            case Keyboard.CODE_SHIFT: {
+                if (switcher.isShiftedOrShiftLocked()) {
+                    resId = R.string.description_shift_on;
+                } else {
+                    resId = R.string.description_shift_off;
+                }
+                break;
+            }
+
+            case Keyboard.CODE_SWITCH_ALPHA_SYMBOL: {
+                if (switcher.isAlphabetMode()) {
+                    resId = R.string.description_symbols_off;
+                } else {
+                    resId = R.string.description_symbols_on;
+                }
+                break;
+            }
+        }
+
+        if (resId >= 0) {
+            speakDescription(mService.getResources().getText(resId));
+        }
+    }
+
+    /**
+     * Speaks a key's description for accessibility. If a key has an explicit
+     * description defined in keycodes.xml, that will be used. Otherwise, if the
+     * key is a Unicode character, then its character will be used.
+     * <p>
+     * No-op if accessibility is not enabled.
+     * </p>
+     *
+     * @param primaryCode The primary code of the pressed key.
+     * @param switcher The input method's {@link KeyboardSwitcher}.
+     */
+    public void onPress(int primaryCode, KeyboardSwitcher switcher) {
+        if (!isAccessibilityEnabled()) {
+            return;
+        }
+
+        // TODO Use the current keyboard state to read "Switch to symbols"
+        // instead of just "Symbols" (and similar for shift key).
+        CharSequence description = describeKey(primaryCode);
+        if (description == null && Character.isDefined((char) primaryCode)) {
+            description = Character.toString((char) primaryCode);
+        }
+
+        if (description != null) {
+            speakDescription(description);
+        }
+    }
+
+    /**
+     * Returns a text description for a given key code. If the key does not have
+     * an explicit description, returns <code>null</code>.
+     *
+     * @param keyCode An integer key code.
+     * @return A {@link CharSequence} describing the key or <code>null</code> if
+     *         no description is available.
+     */
+    private CharSequence describeKey(int keyCode) {
+        // If not loaded yet, load key descriptions from XML file.
+        if (mDescriptions == null) {
+            mDescriptions = loadDescriptions();
+        }
+
+        return mDescriptions.get(keyCode);
+    }
+
+    /**
+     * Loads key descriptions from resources.
+     */
+    private Map<Integer, CharSequence> loadDescriptions() {
+        final Map<Integer, CharSequence> descriptions = new HashMap<Integer, CharSequence>();
+        final TypedArray array = mService.getResources().obtainTypedArray(R.array.key_descriptions);
+
+        // Key descriptions are stored as a key code followed by a string.
+        for (int i = 0; i < array.length() - 1; i += 2) {
+            int code = array.getInteger(i, 0);
+            CharSequence desc = array.getText(i + 1);
+
+            descriptions.put(code, desc);
+        }
+
+        array.recycle();
+
+        return descriptions;
+    }
+
+    /**
+     * Sends a character sequence to be read aloud.
+     *
+     * @param description The {@link CharSequence} to be read aloud.
+     */
+    private void speakDescription(CharSequence description) {
+        // TODO We need to add an AccessibilityEvent type for IMEs.
+        final AccessibilityEvent event = AccessibilityEvent.obtain(
+                AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED);
+        event.setPackageName(mService.getPackageName());
+        event.setClassName(getClass().getName());
+        event.setAddedCount(description.length());
+        event.getText().add(description);
+
+        mAccessibilityManager.sendAccessibilityEvent(event);
+    }
+}