在画布上画圈时闪烁

Question

我在android上绘图有问题。我正在尝试创建简单的游戏，其中包括将以不同颜色绘制屏幕的机器人。首先，我只尝试在没有任何机器人图像的情况下绘制屏幕（我稍后将它放在更高透明视图上）但是我遇到了闪存画布的问题。

所以这是我的渲染方法。在绘图之前我不能每次canvas.drawColor(Color.BLACK);使用，因为我说机器人需要用自己的颜色（红色和蓝色）绘制屏幕。其他想法是存储每个机器人位置并在每个“渲染”方法上绘制它，但是它需要花费太多时间并且在几秒之后游戏变得非常慢。

public void render(Canvas canvas) {

    if(lastD1X!=-1 && lastD1Y!=-1){
        canvas.drawLine(lastD1X, lastD1Y, droid.getX(), droid.getY(), drawPaint);
    } 
    lastD1X = droid.getX();
    lastD1Y = droid.getY();

    if(lastD2X!=-1 && lastD2Y!=-1){
        canvas.drawLine(lastD2X, lastD2Y, droid2.getX(), droid2.getY(), drawPaint2);
    } 
    lastD2X = droid2.getX();
    lastD2Y = droid2.getY();
}

这是我的游戏循环：

@Override
    public void run() {
        Canvas canvas;
        Log.d(TAG, "Starting game loop");
    long beginTime;     // the time when the cycle begun
    long timeDiff;      // the time it took for the cycle to execute
    int sleepTime;      // ms to sleep (<0 if we're behind)
    int framesSkipped;  // number of frames being skipped 

    sleepTime = 0;

    while (running) {
        canvas = null;
        // try locking the canvas for exclusive pixel editing
        // in the surface
        try {
            canvas = this.surfaceHolder.lockCanvas(null);
            synchronized (surfaceHolder) {
                beginTime = System.currentTimeMillis();
                framesSkipped = 0;  // resetting the frames skipped
                // update game state 
                this.gamePanel.update();
                // render state to the screen
                // draws the canvas on the panel
                this.gamePanel.render(canvas);              
                // calculate how long did the cycle take
                timeDiff = System.currentTimeMillis() - beginTime;
                // calculate sleep time
                sleepTime = (int)(FRAME_PERIOD - timeDiff);

                if (sleepTime > 0) {
                    // if sleepTime > 0 we're OK
                    try {
                        // send the thread to sleep for a short period
                        // very useful for battery saving
                        Thread.sleep(sleepTime);    
                    } catch (InterruptedException e) {}
                }

                while (sleepTime < 0 && framesSkipped < MAX_FRAME_SKIPS) {
                    // we need to catch up
                    this.gamePanel.update(); // update without rendering
                    sleepTime += FRAME_PERIOD;  // add frame period to check if in next frame
                    framesSkipped++;
                }
            }
        } finally {
            // in case of an exception the surface is not left in 
            // an inconsistent state
            if (canvas != null) {
                surfaceHolder.unlockCanvasAndPost(canvas);
            }
        }   // end finally
    }
}