MenuItemCompat.java revision 1935ed3af7c6545bc38adfdc6026d87a3249222f 
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.view;
18
19import android.view.MenuItem;
20import android.view.View;
21
22/**
23 * Helper for accessing newer features in MenuItem.
24 */
25public class MenuItemCompat {
26
27    /**
28     * Never show this item as a button in an Action Bar.
29     */
30    public static final int SHOW_AS_ACTION_NEVER = 0;
31
32    /**
33     * Show this item as a button in an Action Bar if the system
34     * decides there is room for it.
35     */
36    public static final int SHOW_AS_ACTION_IF_ROOM = 1;
37
38    /**
39     * Always show this item as a button in an Action Bar. Use sparingly!
40     * If too many items are set to always show in the Action Bar it can
41     * crowd the Action Bar and degrade the user experience on devices with
42     * smaller screens. A good rule of thumb is to have no more than 2
43     * items set to always show at a time.
44     */
45    public static final int SHOW_AS_ACTION_ALWAYS = 2;
46
47    /**
48     * When this item is in the action bar, always show it with a
49     * text label even if it also has an icon specified.
50     */
51    public static final int SHOW_AS_ACTION_WITH_TEXT = 4;
52
53    /**
54     * This item's action view collapses to a normal menu item.
55     * When expanded, the action view temporarily takes over
56     * a larger segment of its container.
57     */
58    public static final int SHOW_AS_ACTION_COLLAPSE_ACTION_VIEW = 8;
59
60    /**
61     * Interface for the full API.
62     */
63    interface MenuVersionImpl {
64        public boolean setShowAsAction(MenuItem item, int actionEnum);
65        public MenuItem setActionView(MenuItem item, View view);
66    }
67
68    /**
69     * Interface implementation that doesn't use anything about v4 APIs.
70     */
71    static class BaseMenuVersionImpl implements MenuVersionImpl {
72        @Override
73        public boolean setShowAsAction(MenuItem item, int actionEnum) {
74            return false;
75        }
76
77        @Override
78        public MenuItem setActionView(MenuItem item, View view) {
79            return item;
80        }
81    }
82
83    /**
84     * Interface implementation for devices with at least v11 APIs.
85     */
86    static class HoneycombMenuVersionImpl implements MenuVersionImpl {
87        @Override
88        public boolean setShowAsAction(MenuItem item, int actionEnum) {
89            MenuItemCompatHoneycomb.setShowAsAction(item, actionEnum);
90            return true;
91        }
92        @Override
93        public MenuItem setActionView(MenuItem item, View view) {
94            return MenuItemCompatHoneycomb.setActionView(item, view);
95        }
96    }
97
98    /**
99     * Select the correct implementation to use for the current platform.
100     */
101    static final MenuVersionImpl IMPL;
102    static {
103        if (android.os.Build.VERSION.SDK_INT >= 11) {
104            IMPL = new HoneycombMenuVersionImpl();
105        } else {
106            IMPL = new BaseMenuVersionImpl();
107        }
108    }
109
110    // -------------------------------------------------------------------
111
112    /**
113     * Call {@link MenuItem#setShowAsAction(int) MenuItem.setShowAsAction()}.
114     * If running on a pre-{@android.os.Build.VERSION_CODES#HONEYCOMB} device,
115     * does nothing and returns false.  Otherwise returns true.
116     */
117    public static boolean setShowAsAction(MenuItem item, int actionEnum) {
118        return IMPL.setShowAsAction(item, actionEnum);
119    }
120
121    /**
122     * Set an action view for this menu item. An action view will be displayed in place
123     * of an automatically generated menu item element in the UI when this item is shown
124     * as an action within a parent.
125     *
126     * @param view View to use for presenting this item to the user.
127     * @return This Item so additional setters can be called.
128     *
129     * @see #setShowAsAction(MenuItem, int)
130     */
131    public static MenuItem setActionView(MenuItem item, View view) {
132        return IMPL.setActionView(item, view);
133    }
134}
135