ColorDrawable.java revision 41bff38d3060dbcb55133cedaf5d962c3082efc2 
1/*
2 * Copyright (C) 2008 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.graphics.drawable;
18
19import android.graphics.*;
20import android.content.res.Resources;
21import android.content.res.TypedArray;
22import android.util.AttributeSet;
23import org.xmlpull.v1.XmlPullParser;
24import org.xmlpull.v1.XmlPullParserException;
25
26import java.io.IOException;
27
28/**
29 * A specialized Drawable that fills the Canvas with a specified color.
30 * Note that a ColorDrawable ignores the ColorFilter.
31 *
32 * <p>It can be defined in an XML file with the <code>&lt;color></code> element.</p>
33 *
34 * @attr ref android.R.styleable#ColorDrawable_color
35 */
36public class ColorDrawable extends Drawable {
37    private ColorState mState;
38    private final Paint mPaint = new Paint();
39
40    /**
41     * Creates a new black ColorDrawable.
42     */
43    public ColorDrawable() {
44        this(null);
45    }
46
47    /**
48     * Creates a new ColorDrawable with the specified color.
49     *
50     * @param color The color to draw.
51     */
52    public ColorDrawable(int color) {
53        this(null);
54        setColor(color);
55    }
56
57    private ColorDrawable(ColorState state) {
58        mState = new ColorState(state);
59    }
60
61    @Override
62    public int getChangingConfigurations() {
63        return super.getChangingConfigurations() | mState.mChangingConfigurations;
64    }
65
66    @Override
67    public void draw(Canvas canvas) {
68        if ((mState.mUseColor >>> 24) != 0) {
69            mPaint.setColor(mState.mUseColor);
70            canvas.drawRect(getBounds(), mPaint);
71        }
72    }
73
74    /**
75     * Gets the drawable's color value.
76     *
77     * @return int The color to draw.
78     */
79    public int getColor() {
80        return mState.mUseColor;
81    }
82
83    /**
84     * Sets the drawable's color value. This action will clobber the results of prior calls to
85     * {@link #setAlpha(int)} on this object, which side-affected the underlying color.
86     *
87     * @param color The color to draw.
88     */
89    public void setColor(int color) {
90        if (mState.mBaseColor != color || mState.mUseColor != color) {
91            invalidateSelf();
92            mState.mBaseColor = mState.mUseColor = color;
93        }
94    }
95
96    /**
97     * Returns the alpha value of this drawable's color.
98     *
99     * @return A value between 0 and 255.
100     */
101    public int getAlpha() {
102        return mState.mUseColor >>> 24;
103    }
104
105    /**
106     * Sets the color's alpha value.
107     *
108     * @param alpha The alpha value to set, between 0 and 255.
109     */
110    public void setAlpha(int alpha) {
111        alpha += alpha >> 7;   // make it 0..256
112        int baseAlpha = mState.mBaseColor >>> 24;
113        int useAlpha = baseAlpha * alpha >> 8;
114        int oldUseColor = mState.mUseColor;
115        mState.mUseColor = (mState.mBaseColor << 8 >>> 8) | (useAlpha << 24);
116        if (oldUseColor != mState.mUseColor) {
117            invalidateSelf();
118        }
119    }
120
121    /**
122     * Setting a color filter on a ColorDrawable has no effect.
123     *
124     * @param colorFilter Ignore.
125     */
126    public void setColorFilter(ColorFilter colorFilter) {
127    }
128
129    public int getOpacity() {
130        switch (mState.mUseColor >>> 24) {
131            case 255:
132                return PixelFormat.OPAQUE;
133            case 0:
134                return PixelFormat.TRANSPARENT;
135        }
136        return PixelFormat.TRANSLUCENT;
137    }
138
139    @Override
140    public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs)
141            throws XmlPullParserException, IOException {
142        super.inflate(r, parser, attrs);
143
144        TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.ColorDrawable);
145
146        int color = mState.mBaseColor;
147        color = a.getColor(com.android.internal.R.styleable.ColorDrawable_color, color);
148        mState.mBaseColor = mState.mUseColor = color;
149
150        a.recycle();
151    }
152
153    @Override
154    public ConstantState getConstantState() {
155        mState.mChangingConfigurations = getChangingConfigurations();
156        return mState;
157    }
158
159    final static class ColorState extends ConstantState {
160        int mBaseColor; // base color, independent of setAlpha()
161        int mUseColor;  // basecolor modulated by setAlpha()
162        int mChangingConfigurations;
163
164        ColorState(ColorState state) {
165            if (state != null) {
166                mBaseColor = state.mBaseColor;
167                mUseColor = state.mUseColor;
168            }
169        }
170
171        @Override
172        public Drawable newDrawable() {
173            return new ColorDrawable(this);
174        }
175
176        @Override
177        public Drawable newDrawable(Resources res) {
178            return new ColorDrawable(this);
179        }
180
181        @Override
182        public int getChangingConfigurations() {
183            return mChangingConfigurations;
184        }
185    }
186}
187