<!-- 访问网络权限 --><uses-permission android:name="android.permission.INTERNET" />

new Thread(new Runnable() {URL url;@Overridepublic void run() {// TODO Auto-generated method stubtry {url = new URL("http://99touxiang.com/public/upload/rihan/15/13-042315_940.jpg");inputStream = url.openStream();// 将字节流转换为Bitmap,使用BitmapFactory工厂类进行转换Bitmap bitmap = BitmapFactory.decodeStream(inputStream);output = getRoundedCornerBitmap(bitmap);header_image.post(new Runnable() {@Overridepublic void run() {// TODO Auto-generated method stub// 更新界面
                            header_image.setImageBitmap(output);}});} catch (MalformedURLException e) {// TODO Auto-generated catch block
                    e.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch block
                    e.printStackTrace();}}}).start();

1  

 /* 圆形头像
 2      *
 3      * @param bitmap
 4      * @param ratio
 5      *            按照截取比例来获取圆形图片
 6      * @return
 7      */
 8     public Bitmap getRoundedCornerBitmap(Bitmap bitmap) {
 9         if (bitmap == null) {
10             bitmap = BitmapFactory.decodeStream(inputStream);
11         }
12         Bitmap outBitmap = Bitmap.createBitmap(bitmap.getWidth(),
13                 bitmap.getHeight(), Config.ARGB_8888);//Bitmap.Config.ARGB_4444比Bitmap.Config.ARGB_8888更省内存
14         Canvas canvas = new Canvas(outBitmap);
15         final int color = 0xff424242;
16         final Paint paint = new Paint();
17         final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
18         final RectF rectF = new RectF(rect);
19         final float roundPX = bitmap.getWidth() / 2 < bitmap.getHeight() / 2 ? bitmap
20                 .getWidth() : bitmap.getHeight();
21         paint.setAntiAlias(true);
22         canvas.drawARGB(0, 0, 0, 0);
23         paint.setColor(color);
24         canvas.drawRoundRect(rectF, roundPX, roundPX, paint);
25         paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
26         canvas.drawBitmap(bitmap, rect, rect, paint);
27         return outBitmap;
28     }
29