Android圆角图片封装类

import android.content.Context;  
import android.graphics.Canvas;  
import android.graphics.Color;  
import android.graphics.Paint;  
import android.graphics.PorterDuff;  
import android.graphics.PorterDuffXfermode;  
import android.graphics.RectF;  
import android.util.AttributeSet;  
import android.widget.ImageView;  
  
/** 
 * 圆角ImageView 
 *  
 * @author skg 
 *  
 */  
public class RoundImageView extends ImageView {  
  
    public RoundImageView(Context context,AttributeSet attrs) {  
        super(context,attrs);  
        init();  
    }  
  
    public RoundImageView(Context context) {  
        super(context);  
        init();  
    }  
  
    private final RectF roundRect = new RectF();  
    private float rect_adius = 6;  
    private final Paint maskPaint = new Paint();  
    private final Paint zonePaint = new Paint();  
  
    private void init() {  
        maskPaint.setAntiAlias(true);  
        maskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));  
        //  
        zonePaint.setAntiAlias(true);  
        zonePaint.setColor(Color.WHITE);  
        //  
        float density = getResources().getDisplayMetrics().density;  
        rect_adius = rect_adius * density;  
    }  
  
    public void setRectAdius(float adius) {  
        rect_adius = adius;  
        invalidate();  
    }  
  
    @Override  
    protected void onLayout(boolean changed,int left,int top,int right,int bottom) {  
        super.onLayout(changed,left,top,right,bottom);  
        int w = getWidth();  
        int h = getHeight();  
        roundRect.set(0,w,h);  
    }  
  
    @Override  
    public void draw(Canvas canvas) {  
        canvas.saveLayer(roundRect,zonePaint,Canvas.ALL_SAVE_FLAG);  
        canvas.drawRoundRect(roundRect,rect_adius,zonePaint);  
        //  
        canvas.saveLayer(roundRect,maskPaint,Canvas.ALL_SAVE_FLAG);  
        super.draw(canvas);  
        canvas.restore();  
    }  
  
}