public Bitmap getRoundBitmap(Bitmap bitmap) 
{
    int d = Math.min(bitmap.getWidth(), bitmap.getHeight());

    Bitmap output = Bitmap.createBitmap(d, d, Config.ARGB_8888);
    Canvas canvas = new Canvas(output);

    int r = d / 2;

    final Paint paint = new Paint();
    final Rect rect = new Rect(0, 0, d, d);
    final RectF rectF = new RectF(rect);

    paint.setAntiAlias(true);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(0xFFFFFFFF);
    canvas.drawRoundRect(rectF, r, r, paint);
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    canvas.drawBitmap(bitmap, rect, rect, paint);

    // 加上白边
    Paint p = new Paint();
    p.setAntiAlias(true);
    p.setColor(Color.WHITE);
    p.setStyle(Style.STROKE);
    p.setStrokeWidth(r/25);
    p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    canvas.drawCircle(r, r, r, p);

    return output;
}