我是否做得不正确或不理解 Android 上的双缓冲？
我有一个函数
@Override
public void run() {
while(running && (!eof)){
if(surfaceHolder.getSurface().isValid()){
Canvas canvas = surfaceHolder.lockCanvas();
paint(canvas);
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
thread = null;
}
，其中 Paint(canvas) 调用一堆其他函数来绘制图形和文本，例如，
canvas.drawText("Time="+myRecord.getMyTime(), 100, 100, paint);
我遇到的问题是图形和文本，两者都应该不断变化，而不是被抹掉了，而是继续在自己身上画画。我的整个画布不应该每次都重新绘制吗，因为这就是双缓冲与lock()和unlock()一起工作的方式？我对此理解不正确吗？我该怎么做？
I have a function
@Override
public void run() {
while(running && (!eof)){
if(surfaceHolder.getSurface().isValid()){
Canvas canvas = surfaceHolder.lockCanvas();
paint(canvas);
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
thread = null;
}
where paint(canvas) calls a bunch of other functions that draw a graph and text, for example
canvas.drawText("Time="+myRecord.getMyTime(), 100, 100, paint);
The problem I'm having is that the graph and the text, both of which should be constantly changing, don't get erased but instead keep drawing over themselves. Shouldn't my entire canvas get redrawn every time because that's how double buffering works with the lock() and unlock()? Am I not understanding this correctly? How am I supposed to do this?
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您需要在 lockCanvas() 之后使用 Canvas.drawColor() 自行清除 Canvas。
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You need to clear the Canvas yourself after lockCanvas() using Canvas.drawColor().
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