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/*
* Copyright (C) 2007 The Android Open Source Project
*
* 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 android.util;
import com.android.internal.R;
/**
* State sets are arrays of positive ints where each element
* represents the state of a {@link android.view.View} (e.g. focused,
* selected, visible, etc.). A {@link android.view.View} may be in
* one or more of those states.
*
* A state spec is an array of signed ints where each element
* represents a required (if positive) or an undesired (if negative)
* {@link android.view.View} state.
*
* Utils dealing with state sets.
*
* In theory we could encapsulate the state set and state spec arrays
* and not have static methods here but there is some concern about
* performance since these methods are called during view drawing.
*/
public class StateSet {
public static final int[] WILD_CARD = new int[0];
/**
* Return whether the stateSetOrSpec is matched by all StateSets.
*
* @param stateSetOrSpec a state set or state spec.
*/
public static boolean isWildCard(int[] stateSetOrSpec) {
return stateSetOrSpec.length == 0 || stateSetOrSpec[0] == 0;
}
/**
* Return whether the stateSet matches the desired stateSpec.
*
* @param stateSpec an array of required (if positive) or
* prohibited (if negative) {@link android.view.View} states.
* @param stateSet an array of {@link android.view.View} states
*/
public static boolean stateSetMatches(int[] stateSpec, int[] stateSet) {
if (stateSet == null) {
return (stateSpec == null || isWildCard(stateSpec));
}
int stateSpecSize = stateSpec.length;
int stateSetSize = stateSet.length;
for (int i = 0; i < stateSpecSize; i++) {
int stateSpecState = stateSpec[i];
if (stateSpecState == 0) {
// We've reached the end of the cases to match against.
return true;
}
final boolean mustMatch;
if (stateSpecState > 0) {
mustMatch = true;
} else {
// We use negative values to indicate must-NOT-match states.
mustMatch = false;
stateSpecState = -stateSpecState;
}
boolean found = false;
for (int j = 0; j < stateSetSize; j++) {
final int state = stateSet[j];
if (state == 0) {
// We've reached the end of states to match.
if (mustMatch) {
// We didn't find this must-match state.
return false;
} else {
// Continue checking other must-not-match states.
break;
}
}
if (state == stateSpecState) {
if (mustMatch) {
found = true;
// Continue checking other other must-match states.
break;
} else {
// Any match of a must-not-match state returns false.
return false;
}
}
}
if (mustMatch && !found) {
// We've reached the end of states to match and we didn't
// find a must-match state.
return false;
}
}
return true;
}
/**
* Return whether the state matches the desired stateSpec.
*
* @param stateSpec an array of required (if positive) or
* prohibited (if negative) {@link android.view.View} states.
* @param state a {@link android.view.View} state
*/
public static boolean stateSetMatches(int[] stateSpec, int state) {
int stateSpecSize = stateSpec.length;
for (int i = 0; i < stateSpecSize; i++) {
int stateSpecState = stateSpec[i];
if (stateSpecState == 0) {
// We've reached the end of the cases to match against.
return true;
}
if (stateSpecState > 0) {
if (state != stateSpecState) {
return false;
}
} else {
// We use negative values to indicate must-NOT-match states.
if (state == -stateSpecState) {
// We matched a must-not-match case.
return false;
}
}
}
return true;
}
public static int[] trimStateSet(int[] states, int newSize) {
if (states.length == newSize) {
return states;
}
int[] trimmedStates = new int[newSize];
System.arraycopy(states, 0, trimmedStates, 0, newSize);
return trimmedStates;
}
public static String dump(int[] states) {
StringBuilder sb = new StringBuilder();
int count = states.length;
for (int i = 0; i < count; i++) {
switch (states[i]) {
case R.attr.state_window_focused:
sb.append("W ");
break;
case R.attr.state_pressed:
sb.append("P ");
break;
case R.attr.state_selected:
sb.append("S ");
break;
case R.attr.state_focused:
sb.append("F ");
break;
case R.attr.state_enabled:
sb.append("E ");
break;
}
}
return sb.toString();
}
}
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