Android FPS，如何使其更流畅？

Question

I am having trouble in constructing a basic game loop for my game. I am at the early phase and all I want to do is to move the the ball at a constant speed (for ex: 3) through the bottom of the screen. The position of the ball is updated in the main panel update method and it is drawed in the render part as expected. Nothing exceptional in the mechanism. The ball moves but it is definitely not smooth, the visual is quiet disturbing.. I measured the implementation times of these methods and the total implementation time of this couple is about 3-4 milliseconds. Under these circumstances, what is the suitable FPS? Are the given constant values suitable What is missing or wrong in my mechanism? Thanks a lot in advance. the code block in main thread.

private final static int MAX_FPS = 200;
private final static int FRAME_PERIOD = 1000 / MAX_FPS;
private final static int    MAX_FRAME_SKIPS = 5;

public void run() {

    initTimingElements();
    long beginTime;
    long timeDiff;
    int sleepTime;
    int framesSkipped;
    long beginTime2;

    long diff1;
    long diff2;

    sleepTime = 0;

    Canvas canvas;
    Log.d(TAG, "Starting game loop");
    while (running) {
        canvas = null;
        try {
            canvas = this.surfaceHolder.lockCanvas();
            synchronized (surfaceHolder) {
                beginTime = System.currentTimeMillis();
                framesSkipped = 0; 

                this.gamePanel.update();
                diff1=System.currentTimeMillis()-beginTime;
                beginTime2=System.currentTimeMillis();
                this.gamePanel.render(canvas);
                diff2=System.currentTimeMillis()-beginTime2;



                timeDiff = System.currentTimeMillis() - beginTime;
                sleepTime = (int) (FRAME_PERIOD - timeDiff);

                if (sleepTime > 0) {
                    try {
                        Thread.sleep(sleepTime);
                    } catch (InterruptedException e) {
                    }
                }                   
                while (sleepTime < 0 && framesSkipped < MAX_FRAME_SKIPS) {
                    this.gamePanel.update();
                    sleepTime += FRAME_PERIOD;
                    framesSkipped++;
                }
                if (framesSkipped > 0) {
                    Log.d(TAG, "Skipped:" + framesSkipped);
                }
                framesSkippedPerStatCycle += framesSkipped;
                storeStats();
            }
        } finally {
            if (canvas != null) {
                surfaceHolder.unlockCanvasAndPost(canvas);
            }
        }
    }
}

Answer 1

Try using a TimerTask that fires off every 60ms or so.
That's what I do until I stop being lazy enough to do a proper implementation, but it works well. Just remember that run() will be executed in a different thread, so use runOnUIThread() to run whatever code you need.