继承ImageView在上面画圆

public class CustomView extends ImageView{  public CustomView(Context context, AttributeSet attrs, int defStyle) {      super(context, attrs, defStyle);  }  public CustomView(Context context, AttributeSet attrs) {      super(context, attrs);  }  public CustomView(Context context) {      super(context);  }  boolean drawGlow = false;  //this is the pixel coordinates of the screen  float glowX = 0;  float glowY = 0;  //this is the radius of the circle we are drawing  float radius = 20;  //this is the paint object which specifies the color and alpha level   //of the circle we draw  Paint paint = new Paint();  {      paint.setAntiAlias(true);      paint.setColor(Color.WHITE);      paint.setAlpha(50);  };    @Override  public void draw(Canvas canvas){      super.draw(canvas);      if(drawGlow)          canvas.drawCircle(glowX, glowY, radius, paint);  }  @Override  public boolean onTouchEvent(MotionEvent event){      if(event.getAction() == MotionEvent.ACTION_DOWN){          drawGlow = true;      }else if(event.getAction() == MotionEvent.ACTION_UP)          drawGlow = false;        glowX = event.getX();      glowY = event.getY();      this.invalidate();      return true;  }  

 

 

上面的CustomView你也可以在xml中引用只是你需要加包名