android 入门-onDraw()

 

canvas.drawBitmap(bitmap, srcRect, dstRect, paint)，将图片指定区域，画到canvas的指定区域

 

@Override  
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)     
{   
    height = View.MeasureSpec.getSize(heightMeasureSpec);    
    width = View.MeasureSpec.getSize(widthMeasureSpec);    
    setMeasuredDimension(width,height);  //这里面是原始的大小，需要重新计算可以修改本行   
  //dosomething   
}