我知道这是一个老问题 - 但我也遇到了这个问题，并认为我会分享我的解决方案。

显然CountDownTimer不是很准确，所以我决定实施一个更精确的倒数计时器，usi ng java.util.Timer：

  public abstract class PreciseCountdown extends Timer {
 private long totalTime，interval，delay; 
私有TimerTask任务; 
 private long startTime = -1; 
 private boolean restart = false，wasCancelled = false，wasStarted = false; 

 public PreciseCountdown（long totalTime，long interval）{
 this（totalTime，interval，0）; 
} 

 public PreciseCountdown（long totalTime，long interval，long delay）{
 super（PreciseCountdown，true）; 
 this.delay = delay; 
 this.interval = interval; 
 this.totalTime = totalTime; 
 this.task = getTask（totalTime）; 
} 

 public void start（）{
 wasStarted = true; 
 this.scheduleAtFixedRate（任务，延迟，间隔）; 
} 

 public void restart（）{
 if（！wasStarted）{
 start（）; 
} 
 else if（wasCancelled）{
 wasCancelled = false; 
 this.task = getTask（totalTime）; 
 start（）; 
} 
 else {
 this.restart = true; 
} 
} 

 public void stop（）{
 this.wasCancelled = true; 
 this.task.cancel（）; 
} 

 //当此计时器没有进一步使用时调用此方法
 public void dispose（）{
 cancel（）; 
 purge（）; 
} 

 private TimerTask getTask（final long totalTime）{
 return new TimerTask（）{

 @Override 
 public void run（ ）{
 long timeLeft; 
 if（startTime< 0 || restart）{
 startTime = scheduledExecutionTime（）; 
 timeLeft = totalTime; 
 restart = false; 
} else {
 timeLeft = totalTime  - （scheduledExecutionTime（） -  startTime）; 

 if（timeLeft< = 0）{
 this.cancel（）; 
 startTime = -1; 
 onFinished（）; 
返回; 
} 
} 

 onTick（timeLeft）; 
} 
}; 
} 

 public abstract void onTick（long timeLeft）; 
 public abstract void onFinished（）; 
} 
 

用法示例如下：

'pre> this.countDown =新PreciseCountdown（TOTALTIME，间隔，延迟）{
@覆盖
公共无效onTick（长的timeleft）{
/ / update ..
//请注意，这是在不同的线程上运行，所以更新任何需要使用的GUI组件Activity.runOnUiThread（）
}

@Override
public void onFinished（）{
onTick（0）; //当计时器结束时onTick不被称为
//倒计时结束
}
};


开始倒计时，只需调用countDown.start（）。
countDown.stop（）停止countDown，可以使用countDown.restart（）重新启动。

希望这对将来的任何人都有帮助。

I am using a countdown timer for audio notification... and it's not accurate from the start...

using initial parameters

private final long startCountDown; 
private final long intervalCountDown;
    ...
    startCountDown = 180 * 1000;   // 3 mns  - to be set from Preferences later
intervalCountDown = 60 * 1000;   // 1 mns - to be set from Preferences later
    ...
    public void onTick(long millisUntilFinished) {
       Log.d(TAG, "notify countDown: " + millisUntilFinished + " msecs");
    }


    countDownTimer = new SwimCountDownTimer(startCountDown,intervalCountDown);
    ....

public void startCountDown() {
    Log.d(TAG, "start countDown for " + startCountDown + " msecs" );
    countDownTimer.start();
}

I can see in the log that the initial countdown is correctly set to 180000 but the next one should be 120000 and it's set to 119945 !!!

04-27 14:50:42.146: I/SWIMMER(8670): notify countDown: 180000 msecs
04-27 14:51:42.206: I/SWIMMER(8670): notify countDown: 119945 msecs

This is quite annoying as the audio notifier is expecting to say only '2 minutes" and not "1 minute and fifty nine seconds" ...; why the interval is not right ... ? I can tricj it in setting myself the text to speech string ... but is there any way to get correct data ?

thanks for suggestions

I know it's an old question- but I've also encountered the problem, and thought I would share my solution.

Apperantly CountDownTimer isn't very accurate, so I've decided to implement a more percise countdown timer, using java.util.Timer:

public abstract class PreciseCountdown extends Timer {
    private long totalTime, interval, delay;
    private TimerTask task;
    private long startTime = -1;
    private boolean restart = false, wasCancelled = false, wasStarted = false;

    public PreciseCountdown(long totalTime, long interval) {
        this(totalTime, interval, 0);
    }

    public PreciseCountdown(long totalTime, long interval, long delay) {
        super("PreciseCountdown", true);
        this.delay = delay;
        this.interval = interval;
        this.totalTime = totalTime;
        this.task = getTask(totalTime);
    }

    public void start() {
        wasStarted = true;
        this.scheduleAtFixedRate(task, delay, interval);
    }

    public void restart() {
        if(!wasStarted) {
            start();
        }
        else if(wasCancelled) {
            wasCancelled = false;
            this.task = getTask(totalTime);
            start();
        }
        else{
            this.restart = true;
        }
    }

    public void stop() {
        this.wasCancelled = true;
        this.task.cancel();
    }

    // Call this when there's no further use for this timer
    public void dispose(){
        cancel();
        purge();
    }

    private TimerTask getTask(final long totalTime) {
        return new TimerTask() {

            @Override
            public void run() {
                long timeLeft;
                if (startTime < 0 || restart) {
                    startTime = scheduledExecutionTime();
                    timeLeft = totalTime;
                    restart = false;
                } else {
                    timeLeft = totalTime - (scheduledExecutionTime() - startTime);

                    if (timeLeft <= 0) {
                        this.cancel();
                        startTime = -1;
                        onFinished();
                        return;
                    }
                }

                onTick(timeLeft);
            }
        };
    }

    public abstract void onTick(long timeLeft);
    public abstract void onFinished();
}

Usage example would be:

this.countDown = new PreciseCountdown(totalTime, interval, delay) {
    @Override
    public void onTick(long timeLeft) {
        // update..
        // note that this runs on a different thread, so to update any GUI components you need to use Activity.runOnUiThread()
    }

    @Override
    public void onFinished() {
        onTick(0); // when the timer finishes onTick isn't called
        // count down is finished
    }
};

to start the countdown, simply call countDown.start(). countDown.stop() stops the countDown, which could be restarted using countDown.restart().

Hope this is any help for anyone in the future.