FocusFinder.java

/*
 * Copyright (C) 2014 Google Inc.
 *
 * 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.utils;

import android.accessibilityservice.AccessibilityService;
import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
import android.util.Log;
import android.view.accessibility.AccessibilityNodeInfo;
import com.android.utils.traversal.NodeFocusFinder;

/**
 * Functions to find focus.
 *
 * NOTE: To give a consistent behaviour, this code should be kept in sync with the relevant subset
 * of code in the {@code CursorController} class in TalkBack.
 */
public class FocusFinder {

    public static final int SEARCH_FORWARD = NodeFocusFinder.SEARCH_FORWARD;
    public static final int SEARCH_BACKWARD = NodeFocusFinder.SEARCH_BACKWARD;

    /** This class should not be instantiated. */
    private FocusFinder() {}

    public static AccessibilityNodeInfoCompat getFocusedNode(AccessibilityService service,
            boolean fallbackOnRoot) {
        AccessibilityNodeInfo root = service.getRootInActiveWindow();
        AccessibilityNodeInfo focused = null;

        try {
            AccessibilityNodeInfo ret = null;
            if (root != null) {
                focused = root.findFocus(AccessibilityNodeInfo.FOCUS_ACCESSIBILITY);
                if (focused != null && focused.isVisibleToUser()) {
                    ret = focused;
                    focused = null;
                } else if (fallbackOnRoot) {
                    ret = root;
                    root = null;
                }
            } else {
                LogUtils.log(service, Log.ERROR, "No current window root");
            }

            if (ret != null) {
                return new AccessibilityNodeInfoCompat(ret);
            }
        } finally {
            if (root != null) {
                root.recycle();
            }

            if (focused != null) {
                focused.recycle();
            }
        }

        return null;
    }
}