简单实现圆形ImageView双层边框

【实例截图】

【核心代码】

package com.example.test;


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

public class RoundImageView extends ImageView {
	private Paint paint;
	private Bitmap bmp;

	public RoundImageView(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
		init();
	}

	public RoundImageView(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
		init();
	}

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

	public void init() {
		paint = new Paint();
		paint.setAntiAlias(true);
		paint.setDither(true);
		paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
	}

	@Override
	protected void onDraw(Canvas canvas) {
		int w = getWidth();
		int h = getHeight();
		Drawable drawable = getDrawable();
		int i = canvas.saveLayer(0.0F, 0.0F, w, h, null, 31);
		int j = getWidth();
		int k = getHeight();
		drawable.setBounds(0, 0, j, k);
		drawable.draw(canvas);

		if (bmp == null){
			bmp = createMask();
		}
		canvas.drawBitmap(bmp, 0.0F, 0.0F, paint);
		canvas.restoreToCount(i);

	}

	public Bitmap createMask() {
		int i = getWidth();
		int j = getHeight();
		Bitmap.Config localConfig = Bitmap.Config.ARGB_8888;
		Bitmap localBitmap = Bitmap.createBitmap(i, j, localConfig);
		Canvas localCanvas = new Canvas(localBitmap);
		Paint localPaint = new Paint(1);
		localPaint.setColor(-16777216);
		float f1 = getWidth();
		float f2 = getHeight();
		RectF localRectF = new RectF(0.0F, 0.0F, f1, f2);
		localCanvas.drawOval(localRectF, localPaint);
		return localBitmap;
	}

}