KeyEventCompat.java revision f185f104c4786740765e549d535f9ba1052f96cc 
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.KeyEvent;
20import android.view.View;
21
22/**
23 * Helper for accessing features in {@link KeyEvent} introduced after
24 * API level 4 in a backwards compatible fashion.
25 */
26public final class KeyEventCompat {
27    /**
28     * Interface for the full API.
29     */
30    interface KeyEventVersionImpl {
31        int normalizeMetaState(int metaState);
32        boolean metaStateHasModifiers(int metaState, int modifiers);
33        boolean metaStateHasNoModifiers(int metaState);
34        boolean isCtrlPressed(KeyEvent event);
35    }
36
37    /**
38     * Interface implementation that doesn't use anything about v4 APIs.
39     */
40    static class BaseKeyEventVersionImpl implements KeyEventVersionImpl {
41        private static final int META_MODIFIER_MASK =
42                KeyEvent.META_SHIFT_ON | KeyEvent.META_SHIFT_LEFT_ON | KeyEvent.META_SHIFT_RIGHT_ON
43                | KeyEvent.META_ALT_ON | KeyEvent.META_ALT_LEFT_ON | KeyEvent.META_ALT_RIGHT_ON
44                | KeyEvent.META_SYM_ON;
45
46        // Mask of all lock key meta states.
47        private static final int META_ALL_MASK = META_MODIFIER_MASK;
48
49        private static int metaStateFilterDirectionalModifiers(int metaState,
50                int modifiers, int basic, int left, int right) {
51            final boolean wantBasic = (modifiers & basic) != 0;
52            final int directional = left | right;
53            final boolean wantLeftOrRight = (modifiers & directional) != 0;
54
55            if (wantBasic) {
56                if (wantLeftOrRight) {
57                    throw new IllegalArgumentException("bad arguments");
58                }
59                return metaState & ~directional;
60            } else if (wantLeftOrRight) {
61                return metaState & ~basic;
62            } else {
63                return metaState;
64            }
65        }
66
67        @Override
68        public int normalizeMetaState(int metaState) {
69            if ((metaState & (KeyEvent.META_SHIFT_LEFT_ON | KeyEvent.META_SHIFT_RIGHT_ON)) != 0) {
70                metaState |= KeyEvent.META_SHIFT_ON;
71            }
72            if ((metaState & (KeyEvent.META_ALT_LEFT_ON | KeyEvent.META_ALT_RIGHT_ON)) != 0) {
73                metaState |= KeyEvent.META_ALT_ON;
74            }
75            return metaState & META_ALL_MASK;
76        }
77
78        @Override
79        public boolean metaStateHasModifiers(int metaState, int modifiers) {
80            metaState = normalizeMetaState(metaState) & META_MODIFIER_MASK;
81            metaState = metaStateFilterDirectionalModifiers(metaState, modifiers,
82                    KeyEvent.META_SHIFT_ON, KeyEvent.META_SHIFT_LEFT_ON, KeyEvent.META_SHIFT_RIGHT_ON);
83            metaState = metaStateFilterDirectionalModifiers(metaState, modifiers,
84                    KeyEvent.META_ALT_ON, KeyEvent.META_ALT_LEFT_ON, KeyEvent.META_ALT_RIGHT_ON);
85            return metaState == modifiers;
86        }
87
88        @Override
89        public boolean metaStateHasNoModifiers(int metaState) {
90            return (normalizeMetaState(metaState) & META_MODIFIER_MASK) == 0;
91        }
92
93        @Override
94        public boolean isCtrlPressed(KeyEvent event) {
95            return false;
96        }
97    }
98
99    /**
100     * Interface implementation for devices with at least v11 APIs.
101     */
102    static class HoneycombKeyEventVersionImpl extends BaseKeyEventVersionImpl {
103        @Override
104        public int normalizeMetaState(int metaState) {
105            return KeyEventCompatHoneycomb.normalizeMetaState(metaState);
106        }
107
108        @Override
109        public boolean metaStateHasModifiers(int metaState, int modifiers) {
110            return KeyEventCompatHoneycomb.metaStateHasModifiers(metaState, modifiers);
111        }
112
113        @Override
114        public boolean metaStateHasNoModifiers(int metaState) {
115            return KeyEventCompatHoneycomb.metaStateHasNoModifiers(metaState);
116        }
117
118        @Override
119        public boolean isCtrlPressed(KeyEvent event) {
120            return KeyEventCompatHoneycomb.isCtrlPressed(event);
121        }
122    }
123
124    /**
125     * Select the correct implementation to use for the current platform.
126     */
127    static final KeyEventVersionImpl IMPL;
128    static {
129        if (android.os.Build.VERSION.SDK_INT >= 11) {
130            IMPL = new HoneycombKeyEventVersionImpl();
131        } else {
132            IMPL = new BaseKeyEventVersionImpl();
133        }
134    }
135
136    // -------------------------------------------------------------------
137
138    public static int normalizeMetaState(int metaState) {
139        return IMPL.normalizeMetaState(metaState);
140    }
141
142    public static boolean metaStateHasModifiers(int metaState, int modifiers) {
143        return IMPL.metaStateHasModifiers(metaState, modifiers);
144    }
145
146    public static boolean metaStateHasNoModifiers(int metaState) {
147        return IMPL.metaStateHasNoModifiers(metaState);
148    }
149
150    public static boolean hasModifiers(KeyEvent event, int modifiers) {
151        return IMPL.metaStateHasModifiers(event.getMetaState(), modifiers);
152    }
153
154    public static boolean hasNoModifiers(KeyEvent event) {
155        return IMPL.metaStateHasNoModifiers(event.getMetaState());
156    }
157
158    /**
159     * @deprecated Call {@link KeyEvent#startTracking()} directly.
160     */
161    @Deprecated
162    public static void startTracking(KeyEvent event) {
163        event.startTracking();
164    }
165
166    /**
167     * @deprecated Call {@link KeyEvent#isTracking()} directly.
168     */
169    @Deprecated
170    public static boolean isTracking(KeyEvent event) {
171        return event.isTracking();
172    }
173
174    /**
175     * @deprecated Call {@link View#getKeyDispatcherState()} directly.
176     */
177    @Deprecated
178    public static Object getKeyDispatcherState(View view) {
179        return view.getKeyDispatcherState();
180    }
181
182    /**
183     * @deprecated Call
184     * {@link KeyEvent#dispatch(KeyEvent.Callback, KeyEvent.DispatcherState, Object)} directly.
185     */
186    @Deprecated
187    public static boolean dispatch(KeyEvent event, KeyEvent.Callback receiver, Object state,
188                Object target) {
189        return event.dispatch(receiver, (KeyEvent.DispatcherState)state, target);
190    }
191
192    public static boolean isCtrlPressed(KeyEvent event) {
193        return IMPL.isCtrlPressed(event);
194    }
195
196    private KeyEventCompat() {}
197}
198