1 /*
2  * Copyright (C) 2007 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 
17 package android.util;
18 
19 import com.android.internal.R;
20 
21 /**
22  * State sets are arrays of positive ints where each element
23  * represents the state of a {@link android.view.View} (e.g. focused,
24  * selected, visible, etc.).  A {@link android.view.View} may be in
25  * one or more of those states.
26  *
27  * A state spec is an array of signed ints where each element
28  * represents a required (if positive) or an undesired (if negative)
29  * {@link android.view.View} state.
30  *
31  * Utils dealing with state sets.
32  *
33  * In theory we could encapsulate the state set and state spec arrays
34  * and not have static methods here but there is some concern about
35  * performance since these methods are called during view drawing.
36  */
37 
38 public class StateSet {
39     /**
40      * The order here is very important to
41      * {@link android.view.View#getDrawableState()}
42      */
43     private static final int[][] VIEW_STATE_SETS;
44 
45     /** @hide */
46     public static final int VIEW_STATE_WINDOW_FOCUSED = 1;
47     /** @hide */
48     public static final int VIEW_STATE_SELECTED = 1 << 1;
49     /** @hide */
50     public static final int VIEW_STATE_FOCUSED = 1 << 2;
51     /** @hide */
52     public static final int VIEW_STATE_ENABLED = 1 << 3;
53     /** @hide */
54     public static final int VIEW_STATE_PRESSED = 1 << 4;
55     /** @hide */
56     public static final int VIEW_STATE_ACTIVATED = 1 << 5;
57     /** @hide */
58     public static final int VIEW_STATE_ACCELERATED = 1 << 6;
59     /** @hide */
60     public static final int VIEW_STATE_HOVERED = 1 << 7;
61     /** @hide */
62     public static final int VIEW_STATE_DRAG_CAN_ACCEPT = 1 << 8;
63     /** @hide */
64     public static final int VIEW_STATE_DRAG_HOVERED = 1 << 9;
65 
66     static final int[] VIEW_STATE_IDS = new int[] {
67             R.attr.state_window_focused,    VIEW_STATE_WINDOW_FOCUSED,
68             R.attr.state_selected,          VIEW_STATE_SELECTED,
69             R.attr.state_focused,           VIEW_STATE_FOCUSED,
70             R.attr.state_enabled,           VIEW_STATE_ENABLED,
71             R.attr.state_pressed,           VIEW_STATE_PRESSED,
72             R.attr.state_activated,         VIEW_STATE_ACTIVATED,
73             R.attr.state_accelerated,       VIEW_STATE_ACCELERATED,
74             R.attr.state_hovered,           VIEW_STATE_HOVERED,
75             R.attr.state_drag_can_accept,   VIEW_STATE_DRAG_CAN_ACCEPT,
76             R.attr.state_drag_hovered,      VIEW_STATE_DRAG_HOVERED
77     };
78 
79     static {
80         if ((VIEW_STATE_IDS.length / 2) != R.styleable.ViewDrawableStates.length) {
81             throw new IllegalStateException(
82                     "VIEW_STATE_IDs array length does not match ViewDrawableStates style array");
83         }
84 
85         final int[] orderedIds = new int[VIEW_STATE_IDS.length];
86         for (int i = 0; i < R.styleable.ViewDrawableStates.length; i++) {
87             final int viewState = R.styleable.ViewDrawableStates[i];
88             for (int j = 0; j < VIEW_STATE_IDS.length; j += 2) {
89                 if (VIEW_STATE_IDS[j] == viewState) {
90                     orderedIds[i * 2] = viewState;
91                     orderedIds[i * 2 + 1] = VIEW_STATE_IDS[j + 1];
92                 }
93             }
94         }
95 
96         final int NUM_BITS = VIEW_STATE_IDS.length / 2;
97         VIEW_STATE_SETS = new int[1 << NUM_BITS][];
98         for (int i = 0; i < VIEW_STATE_SETS.length; i++) {
99             final int numBits = Integer.bitCount(i);
100             final int[] set = new int[numBits];
101             int pos = 0;
102             for (int j = 0; j < orderedIds.length; j += 2) {
103                 if ((i & orderedIds[j + 1]) != 0) {
104                     set[pos++] = orderedIds[j];
105                 }
106             }
107             VIEW_STATE_SETS[i] = set;
108         }
109     }
110 
111     /** @hide */
get(int mask)112     public static int[] get(int mask) {
113         if (mask >= VIEW_STATE_SETS.length) {
114             throw new IllegalArgumentException("Invalid state set mask");
115         }
116         return VIEW_STATE_SETS[mask];
117     }
118 
119     /** @hide */
StateSet()120     public StateSet() {}
121 
122     /**
123      * A state specification that will be matched by all StateSets.
124      */
125     public static final int[] WILD_CARD = new int[0];
126 
127     /**
128      * A state set that does not contain any valid states.
129      */
130     public static final int[] NOTHING = new int[] { 0 };
131 
132     /**
133      * Return whether the stateSetOrSpec is matched by all StateSets.
134      *
135      * @param stateSetOrSpec a state set or state spec.
136      */
isWildCard(int[] stateSetOrSpec)137     public static boolean isWildCard(int[] stateSetOrSpec) {
138         return stateSetOrSpec.length == 0 || stateSetOrSpec[0] == 0;
139     }
140 
141     /**
142      * Return whether the stateSet matches the desired stateSpec.
143      *
144      * @param stateSpec an array of required (if positive) or
145      *        prohibited (if negative) {@link android.view.View} states.
146      * @param stateSet an array of {@link android.view.View} states
147      */
stateSetMatches(int[] stateSpec, int[] stateSet)148     public static boolean stateSetMatches(int[] stateSpec, int[] stateSet) {
149         if (stateSet == null) {
150             return (stateSpec == null || isWildCard(stateSpec));
151         }
152         int stateSpecSize = stateSpec.length;
153         int stateSetSize = stateSet.length;
154         for (int i = 0; i < stateSpecSize; i++) {
155             int stateSpecState = stateSpec[i];
156             if (stateSpecState == 0) {
157                 // We've reached the end of the cases to match against.
158                 return true;
159             }
160             final boolean mustMatch;
161             if (stateSpecState > 0) {
162                 mustMatch = true;
163             } else {
164                 // We use negative values to indicate must-NOT-match states.
165                 mustMatch = false;
166                 stateSpecState = -stateSpecState;
167             }
168             boolean found = false;
169             for (int j = 0; j < stateSetSize; j++) {
170                 final int state = stateSet[j];
171                 if (state == 0) {
172                     // We've reached the end of states to match.
173                     if (mustMatch) {
174                         // We didn't find this must-match state.
175                         return false;
176                     } else {
177                         // Continue checking other must-not-match states.
178                         break;
179                     }
180                 }
181                 if (state == stateSpecState) {
182                     if (mustMatch) {
183                         found = true;
184                         // Continue checking other other must-match states.
185                         break;
186                     } else {
187                         // Any match of a must-not-match state returns false.
188                         return false;
189                     }
190                 }
191             }
192             if (mustMatch && !found) {
193                 // We've reached the end of states to match and we didn't
194                 // find a must-match state.
195                 return false;
196             }
197         }
198         return true;
199     }
200 
201     /**
202      * Return whether the state matches the desired stateSpec.
203      *
204      * @param stateSpec an array of required (if positive) or
205      *        prohibited (if negative) {@link android.view.View} states.
206      * @param state a {@link android.view.View} state
207      */
stateSetMatches(int[] stateSpec, int state)208     public static boolean stateSetMatches(int[] stateSpec, int state) {
209         int stateSpecSize = stateSpec.length;
210         for (int i = 0; i < stateSpecSize; i++) {
211             int stateSpecState = stateSpec[i];
212             if (stateSpecState == 0) {
213                 // We've reached the end of the cases to match against.
214                 return true;
215             }
216             if (stateSpecState > 0) {
217                 if (state != stateSpecState) {
218                    return false;
219                 }
220             } else {
221                 // We use negative values to indicate must-NOT-match states.
222                 if (state == -stateSpecState) {
223                     // We matched a must-not-match case.
224                     return false;
225                 }
226             }
227         }
228         return true;
229     }
230 
trimStateSet(int[] states, int newSize)231     public static int[] trimStateSet(int[] states, int newSize) {
232         if (states.length == newSize) {
233             return states;
234         }
235 
236         int[] trimmedStates = new int[newSize];
237         System.arraycopy(states, 0, trimmedStates, 0, newSize);
238         return trimmedStates;
239     }
240 
dump(int[] states)241     public static String dump(int[] states) {
242         StringBuilder sb = new StringBuilder();
243 
244         int count = states.length;
245         for (int i = 0; i < count; i++) {
246 
247             switch (states[i]) {
248             case R.attr.state_window_focused:
249                 sb.append("W ");
250                 break;
251             case R.attr.state_pressed:
252                 sb.append("P ");
253                 break;
254             case R.attr.state_selected:
255                 sb.append("S ");
256                 break;
257             case R.attr.state_focused:
258                 sb.append("F ");
259                 break;
260             case R.attr.state_enabled:
261                 sb.append("E ");
262                 break;
263             }
264         }
265 
266         return sb.toString();
267     }
268 }
269