我试图更改自定义视图的背景图像,有些成功。图片会改变,但问题是我仍然看到旧图片的痕迹。当我尝试在绘制新图片之前清除画布时,它似乎不起作用。我创建一个位图来存储图片。在更改图片时,我在绘制新图片之前调用Canvas.drawColor(),但旧图片仍然存在。我尝试了drawColor(0),drawColor(Color.BLACK),c.drawColor(0, PorterDuff.Mode.CLEAR)等方法,但以上都不起作用。因此,我不得不向比我更有经验的人请教。实际代码如下:
private int bgnd;
private boolean switching;
public void setBgnd(int incoming){
switching = true;
switch (incoming){
case R.drawable.image1:
bgnd = incoming;
this.invalidate();
break;
case R.drawable.image2:
bgnd = incoming;
this.invalidate();
break;
}
}
protected void onDraw(Canvas c){
if(switching == true){
Bitmap b = BitmapFactory.decodeResource(getResources(), bgnd);
c.drawColor(0, PorterDuff.Mode.CLEAR);
c.drawBitmap(b, 0, 0, null);
switching = false;
}else{
Bitmap b = BitmapFactory.decodeResource(getResources(), bgnd);
c.drawBitmap(b, 0, 0, null);
}
}