自定义圆形图片

package com.example.asus.myapplication;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.NinePatchDrawable;
import android.util.AttributeSet;
import android.widget.ImageView;

public class MyImageView extends ImageView {

   private int defaultWidth;
   private int defaultHeight;

   public MyImageView(Context context, AttributeSet attrs, int defStyle) {
      super(context, attrs, defStyle);
      // TODO Auto-generated constructor stub
   }

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

   public MyImageView(Context context) {
      super(context);
      // TODO Auto-generated constructor stub
   }
   @Override 

    protected void onDraw(Canvas canvas) { 

        Drawable drawable = getDrawable(); 

        if (drawable == null) { 

            return; 

        } 

 

        if (getWidth() == 0 || getHeight() == 0) { 

            return; 

        } 

        this.measure(0, 0); 

        if (drawable.getClass() == NinePatchDrawable.class) 

            return; 

        Bitmap b = ((BitmapDrawable)drawable).getBitmap(); 

        Bitmap bitmap = b.copy(Config.ARGB_8888, true);

        if (defaultWidth == 0) { 

            defaultWidth = getWidth(); 

 

        } 

        if (defaultHeight == 0) { 

            defaultHeight = getHeight(); 

        } 

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