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Android example source code file (ColorDrawable.java)

This example Android source code file (ColorDrawable.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, attributeset, colordrawable, colorstate, constantstate, content, drawable, drawing, graphics, io, ioexception, override, paint, typedarray, xmlpullparser, xmlpullparserexception

The ColorDrawable.java Android example source code

/*
 * Copyright (C) 2008 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.graphics.drawable;

import android.graphics.*;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;

/**
 * A specialized Drawable that fills the Canvas with a specified color,
 * with respect to the clip region. Note that a ColorDrawable ignores the ColorFilter.
 * It also ignores the Bounds, meaning it will draw everywhere in the current clip,
 * even if setBounds(...) was called with a smaller area.
 *
 * <p>It can be defined in an XML file with the <color> element.

* * @attr ref android.R.styleable#ColorDrawable_color */ public class ColorDrawable extends Drawable { private ColorState mState; /** * Creates a new black ColorDrawable. */ public ColorDrawable() { this(null); } /** * Creates a new ColorDrawable with the specified color. * * @param color The color to draw. */ public ColorDrawable(int color) { this(null); mState.mBaseColor = mState.mUseColor = color; } private ColorDrawable(ColorState state) { mState = new ColorState(state); } @Override public int getChangingConfigurations() { return super.getChangingConfigurations() | mState.mChangingConfigurations; } @Override public void draw(Canvas canvas) { canvas.drawColor(mState.mUseColor); } /** * Returns the alpha value of this drawable's color. * * @return A value between 0 and 255. */ public int getAlpha() { return mState.mUseColor >>> 24; } /** * Sets the color's alpha value. * * @param alpha The alpha value to set, between 0 and 255. */ public void setAlpha(int alpha) { alpha += alpha >> 7; // make it 0..256 int baseAlpha = mState.mBaseColor >>> 24; int useAlpha = baseAlpha * alpha >> 8; mState.mUseColor = (mState.mBaseColor << 8 >>> 8) | (useAlpha << 24); } /** * Setting a color filter on a ColorDrawable has no effect. * * @param colorFilter Ignore. */ public void setColorFilter(ColorFilter colorFilter) { } public int getOpacity() { switch (mState.mUseColor >>> 24) { case 255: return PixelFormat.OPAQUE; case 0: return PixelFormat.TRANSPARENT; } return PixelFormat.TRANSLUCENT; } @Override public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) throws XmlPullParserException, IOException { super.inflate(r, parser, attrs); TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.ColorDrawable); int color = mState.mBaseColor; color = a.getColor(com.android.internal.R.styleable.ColorDrawable_color, color); mState.mBaseColor = mState.mUseColor = color; a.recycle(); } @Override public ConstantState getConstantState() { mState.mChangingConfigurations = super.getChangingConfigurations(); return mState; } final static class ColorState extends ConstantState { int mBaseColor; // initial color. never changes int mUseColor; // basecolor modulated by setAlpha() int mChangingConfigurations; ColorState(ColorState state) { if (state != null) { mBaseColor = state.mBaseColor; mUseColor = state.mUseColor; } } @Override public Drawable newDrawable() { return new ColorDrawable(this); } @Override public Drawable newDrawable(Resources res) { return new ColorDrawable(this); } @Override public int getChangingConfigurations() { return mChangingConfigurations; } } }

Other Android examples (source code examples)

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