android 圆角图片

package com.dy;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.widget.ImageView;

public class CircleImage extends ImageView {

	public CircleImage(Context context) {
		super(context);
	}

	public CircleImage(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	public CircleImage(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}
	
	public Bitmap getCircleBitmap(Bitmap bitmap, int angle)  
    {  
        //创建一个和原始图片一样大小位图
        Bitmap originalimage = Bitmap.createBitmap(bitmap.getWidth(),  
                bitmap.getHeight(), Config.ARGB_8888);
        //创建originalimage的画布  
        Canvas canvas = new Canvas(originalimage);  
        //创建画笔  
        Paint paint = new Paint();  
        //创建一个画布一样大小的矩形  
        Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());  
        RectF rectF = new RectF(rect);  
        //去锯齿   
        paint.setAntiAlias(true);  
        //画一个和画布一样大小的椭圆，椭圆的圆形角度是angle
        canvas.drawRoundRect(rectF, angle, angle, paint);
        //设置相交模式

<span style="white-space:pre">	</span>//在正常的情况下，在已有的图像上绘图将会在其上面添加一层新的形状
        //如果新的Paint是完全不透明的，那么它将完全遮挡住下面的Paint
        //而setXfermode就可以来解决这个问题 
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        //把图片画到矩形去 
        canvas.drawBitmap(bitmap, null, rect, paint);  
        return originalimage;  
    }  

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent"
    android:gravity="center"
    android:orientation="vertical" >  
  
    <com.dy.CircleImage  
        android:id="@+id/circleimage"  
        android:layout_width="200dp"  
        android:layout_height="200dp" /> 
</LinearLayout>

package com.dy;

import com.men.text.R;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;

public class HTActivity extends Activity {
	
	private CircleImage circleimage = null;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ht);
		circleimage = (CircleImage)findViewById(R.id.circleimage);  
		
		Bitmap bitmap = (BitmapFactory.decodeResource(getResources(), R.drawable.aa).copy(Bitmap.Config.ARGB_8888, true));
		circleimage.setImageBitmap(circleimage.getCircleBitmap(bitmap, 30));
    }  

}