Android 圆角图形和圆角头像的完美实现

/**
 * 圆角图片控件
 */
public class RoundImageView extends ImageView {

	public RoundImageView(Context context) {
		super(context);
		init();
	}

	public RoundImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		init();
	}

	public RoundImageView(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}
	
	 private final RectF roundRect = new RectF();
	 private float rect_adius = 10;
	 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, 0, w, h);
   }

   @Override
   public void draw(Canvas canvas) {
           try {
			canvas.saveLayer(roundRect, zonePaint, Canvas.ALL_SAVE_FLAG);
			   canvas.drawRoundRect(roundRect, rect_adius, rect_adius, zonePaint);
			   //
			   canvas.saveLayer(roundRect, maskPaint, Canvas.ALL_SAVE_FLAG);
			   super.draw(canvas);
			   canvas.restore();
		} catch (Exception e) {
			e.printStackTrace();
		}
   }
	

}