圆形ImageView的实现

 1 import android.content.Context;
 2 import android.graphics.Paint;
 3 import android.graphics.PaintFlagsDrawFilter;
 4 import android.graphics.Path;
 5 import android.util.AttributeSet;
 6 import android.widget.ImageView;
 7 
 8 import android.graphics.Canvas;
 9 import android.graphics.Color;
10 import android.graphics.Region;
11 
12 /**
13  * 
14  * android circle imageView
15  * 
16  * 
17  */
18 public class CircleImageView extends ImageView {
19 
20     Path path;
21     public PaintFlagsDrawFilter mPaintFlagsDrawFilter;// 毛边过滤
22     Paint paint;
23 
24     public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
25         super(context, attrs, defStyle);
26         // TODO Auto-generated constructor stub
27         init();
28     }
29 
30     public CircleImageView(Context context, AttributeSet attrs) {
31         super(context, attrs);
32         // TODO Auto-generated constructor stub
33         init();
34     }
35 
36     public CircleImageView(Context context) {
37         super(context);
38         // TODO Auto-generated constructor stub
39         init();
40     }
41 
42     public void init() {
43         mPaintFlagsDrawFilter = new PaintFlagsDrawFilter(0,
44                 Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
45         paint = new Paint();
46         paint.setAntiAlias(true);
47         paint.setFilterBitmap(true);
48         paint.setColor(Color.WHITE);
49 
50     }
51 
52     @Override
53     protected void onDraw(Canvas cns) {
54         // TODO Auto-generated method stub
55         float h = getMeasuredHeight();
56         float w = getMeasuredWidth();
57         if (path == null) {
58             path = new Path();
59             path.addCircle(w / 2.0f, h / 2.0f,
60                     (float) Math.min(w / 2.0f, (h / 2.0f)), Path.Direction.CCW);
61             path.close();
62         }
63         cns.drawCircle(w / 2.0f, h / 2.0f, Math.min(w / 2.0f, h / 2.0f), paint);
64         int saveCount = cns.getSaveCount();
65         cns.save();
66         cns.setDrawFilter(mPaintFlagsDrawFilter);
67         cns.clipPath(path, Region.Op.REPLACE);
68         cns.setDrawFilter(mPaintFlagsDrawFilter);
69         cns.drawColor(Color.WHITE);
70         super.onDraw(cns);
71         cns.restoreToCount(saveCount);
72     }
73 
74 }