Android StateListDrawable

 

/**

 *

 * 转载请标明出处：http://blog.csdn.net/u013598111/article/details/50519404

 *   @author：【JunTao_sun】
 *

 *

/



@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

ViewGroup b = (ViewGroup) this.findViewById(android.R.id.content);
ImageView image = (ImageView) this.findViewById(R.id.image);

StateListDrawable drawable = new StateListDrawable();
SpotlightDrawable start = new SpotlightDrawable(this, b);
start.disableOffset();
SpotlightDrawable end = new SpotlightDrawable(this, b,
R.drawable.spotlight_blue);
end.disableOffset();
drawable.addState(new int[] { android.R.attr.state_pressed }, start);
drawable.addState(new int[] {}, end);

drawable.setCallback(image);

image.setBackground(drawable);
image.setClickable(true);
image.requestFocus();

init();
}

* Copyright (C) 2008 Romain Guy
*
* 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 com.example.drawable;

import android.graphics.drawable.Drawable;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.BitmapFactory;
import android.graphics.Bitmap;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.PorterDuff;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.content.Context;
import android.view.ViewGroup;
import android.view.View;

public class SpotlightDrawable extends Drawable {
private final Bitmap mBitmap;
private final Paint mPaint;
private final ViewGroup mView;

private boolean mOffsetDisabled;
private boolean mBlockSetBounds;
private Drawable mParent;

public SpotlightDrawable(Context context, ViewGroup view) {
this(context, view, R.drawable.spotlight);
}

public SpotlightDrawable(Context context, ViewGroup view, int resource) {
mView = view;
mBitmap = BitmapFactory.decodeResource(context.getResources(), resource);

mPaint = new Paint();
//src 和dst 的交集变透明   PorterDuff.Mode.SCREEN模式
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SCREEN));
}

public void draw(Canvas canvas) {
//判断是否取得焦点
if (mView.hasWindowFocus()) {
final Rect bounds = getBounds();
canvas.save();
canvas.drawBitmap(mBitmap, bounds.left, bounds.top, mPaint);
}
}

@Override
public void setBounds(int left, int top, int right, int bottom) {
if (mBlockSetBounds) return;

if (!mOffsetDisabled) {
final int width = getIntrinsicWidth();
final View view = mView.getChildAt(0);
if (view != null) left -= (width - view.getWidth()) / 2.0f;
right = left + width;
bottom = top + getIntrinsicHeight();
} else {
right = left + getIntrinsicWidth();
bottom = top + getIntrinsicHeight();
}

super.setBounds(left, top, right, bottom);

if (mParent != null) {
mBlockSetBounds = true;
mParent.setBounds(left, top, right, bottom);
mBlockSetBounds = false;
}
}

public void setParent(Drawable drawable) {
mParent = drawable;
}

@Override
protected boolean onStateChange(int[] state) {
//通过这个方法重新绘制,其中包含一个Drawable.Callback接口
invalidateSelf();
return super.onStateChange(state);
}

public void setAlpha(int alpha) {
mPaint.setAlpha(alpha);
}

public void setColorFilter(ColorFilter cf) {
mPaint.setColorFilter(cf);
}

public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}

@Override
public int getIntrinsicWidth() {
return mBitmap.getWidth();
}

@Override
public int getIntrinsicHeight() {
return mBitmap.getHeight();
}

public void disableOffset() {
mOffsetDisabled = true;
}
}