Android自定义圆角ImageView，androidimageview,我们经常看到一些app中

Android自定义圆角ImageView，androidimageview,我们经常看到一些app中

我们经常看到一些app中可以显示圆角图片，比如qq的联系人图标等等，实现圆角图片一种办法是直接使用圆角图片资源，当然如果没有圆角图片资源，我们也可以自己通过程序实现的，下面介绍一个自定义圆角ImageView的方法：

import android.content.Context;  import android.content.res.TypedArray;  import android.graphics.Bitmap;  import android.graphics.Bitmap.Config;  import android.graphics.Canvas;  import android.graphics.Color;  import android.graphics.Paint;  import android.graphics.Path;  import android.graphics.PorterDuff;  import android.graphics.PorterDuffXfermode;  import android.graphics.RectF;  import android.util.AttributeSet;  import android.widget.ImageView;  public class RoundAngleImageView extends ImageView {      private int roundWidth = 13;      private int roundHeight = 13;      public RoundAngleImageView(Context context) {          super(context);          init(context, null);      }      public RoundAngleImageView(Context context, AttributeSet attrs, int defStyle) {          super(context, attrs, defStyle);          init(context, attrs);      }      public RoundAngleImageView(Context context, AttributeSet attrs) {          super(context, attrs);          init(context, attrs);      }      private void init(Context context, AttributeSet attrs) {          if (attrs != null) {              TypedArray a = context.obtainStyledAttributes(attrs,                      R.styleable.RoundAngleImageView);              roundWidth = a.getDimensionPixelSize(                      R.styleable.RoundAngleImageView_roundWidth, roundWidth);              roundHeight = a.getDimensionPixelSize(                      R.styleable.RoundAngleImageView_roundHeight, roundHeight);              a.recycle();          } else {              float density = context.getResources().getDisplayMetrics().density;              roundWidth = (int)(roundWidth * density);              roundHeight = (int)(roundHeight * density);          }      }      /** 重写draw() */      @Override      public void draw(Canvas canvas) {          //实例化一个和ImageView一样大小的bitmap          Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(),                  Config.ARGB_8888);          //实例化一个canvas，这个canvas对应的内存为上面的bitmap          Canvas canvas2 = new Canvas(bitmap);          if (bitmap.isRecycled()) {              bitmap = Bitmap.createBitmap(getWidth(), getHeight(),                      Config.ARGB_8888);              canvas2 = new Canvas(bitmap);          }          //将imageView自己绘制到canvas2上，这个导致bitmap里面存放了imageView          super.draw(canvas2);          //利用canvas画一个圆角矩形，这个会修改bitmap的数据          drawRoundAngle(canvas2);          //将裁剪好的bitmap绘制到系统当前canvas上，这样裁剪好的imageview就能显示到屏幕上          Paint paint = new Paint();          paint.setXfermode(null);          canvas.drawBitmap(bitmap, 0, 0, paint);          bitmap.recycle();      }      public void setRoundWidth(int roundWidth, int roundHeight) {          this.roundWidth = roundWidth;          this.roundHeight = roundHeight;      }      private void drawRoundAngle(Canvas canvas)      {          Paint maskPaint = new Paint();          maskPaint.setAntiAlias(true);          maskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));          Path maskPath = new Path();            maskPath.addRoundRect(new RectF(0.0F, 0.0F, getWidth(), getHeight()), roundWidth, roundHeight, Path.Direction.CW);          //这是设置了填充模式，非常关键          maskPath.setFillType(Path.FillType.INVERSE_WINDING);          canvas.drawPath(maskPath, maskPaint);      }  }