ActivityCompat.java revision 14ad84e85a8c09b016a621f0f0017594e0d7864b 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.support.v4.app;
18
19import android.app.Activity;
20import android.os.Build;
21
22/**
23 * Helper for accessing features in {@link android.app.Activity}
24 * introduced after API level 4 in a backwards compatible fashion.
25 */
26public class ActivityCompat {
27    /**
28     * Invalidate the activity's options menu, if able.
29     *
30     * <p>Before API level 11 (Android 3.0/Honeycomb) the lifecycle of the
31     * options menu was controlled primarily by the user's operation of
32     * the hardware menu key. When the user presses down on the menu key
33     * for the first time the menu was created and prepared by calls
34     * to {@link Activity#onCreateOptionsMenu(android.view.Menu)} and
35     * {@link Activity#onPrepareOptionsMenu(android.view.Menu)} respectively.
36     * Subsequent presses of the menu key kept the existing instance of the
37     * Menu itself and called {@link Activity#onPrepareOptionsMenu(android.view.Menu)}
38     * to give the activity an opportunity to contextually alter the menu
39     * before the menu panel was shown.</p>
40     *
41     * <p>In Android 3.0+ the Action Bar forces the options menu to be built early
42     * so that items chosen to show as actions may be displayed when the activity
43     * first becomes visible. The Activity method invalidateOptionsMenu forces
44     * the entire menu to be destroyed and recreated from
45     * {@link Activity#onCreateOptionsMenu(android.view.Menu)}, offering a similar
46     * though heavier-weight opportunity to change the menu's contents. Normally
47     * this functionality is used to support a changing configuration of Fragments.</p>
48     *
49     * <p>Applications may use this support helper to signal a significant change in
50     * activity state that should cause the options menu to be rebuilt. If the app
51     * is running on an older platform version that does not support menu invalidation
52     * the app will still receive {@link Activity#onPrepareOptionsMenu(android.view.Menu)}
53     * the next time the user presses the menu key and this method will return false.
54     * If this method returns true the options menu was successfully invalidated.</p>
55     *
56     * @param activity Invalidate the options menu of this activity
57     * @return true if this operation was supported and it completed; false if it was not available.
58     */
59    public static boolean invalidateOptionsMenu(Activity activity) {
60        if (Build.VERSION.SDK_INT >= 11) {
61            ActivityCompatHoneycomb.invalidateOptionsMenu(activity);
62            return true;
63        }
64        return false;
65    }
66}
67