ScheduledThreadPoolExecutor 只“滴答”一次

Question

我使用CountDownTimer 来实现我在Activity 中的一些倒计时功能。我决定离开CountDownTimer 并使用ScheduledThreadPoolExecutor，因为CountDownTimers 不能在onTick() 中取消自己。

由于某种原因，我在以下代码中的Runnable 只执行一次。我不确定为什么它没有执行多次。 destroyCountdownTimer() 函数未命中。

private ScheduledThreadPoolExecutor mCountdownTimer;
private Tick mTick;

class Tick implements Runnable {
    @Override
    public void run() {
        Log.e("tick", String.valueOf(mAccumulatedMilliseconds));
        mAccumulatedMilliseconds += 1000;
        populateTimeAccumulated();
        populateTimeRemaining();
        updatePercentages();

        if (mTotalMilliseconds <= mAccumulatedMilliseconds) {
            destroyCountdownTimer();
        }
    }
}

private void startCountdown() {
    if (mAccumulatedMilliseconds < mTotalMilliseconds) {
        mCounterIsRunning = true;

        if (mCountdownTimer == null) {
            mCountdownTimer = new ScheduledThreadPoolExecutor(1);
        }

        if (mTick == null) {
            mTick = new Tick();
        }

        mCountdownTimer.scheduleAtFixedRate(mTick, 1000, 1000, TimeUnit.MILLISECONDS);
    }
}

private void destroyCountdownTimer() {
    if (mCountdownTimer != null) {
        mCountdownTimer.shutdownNow();
        mCountdownTimer = null;
    }

    if (mTick != null) {
        mTick = null;
    }
}

Answer 1

documentation 说：

If any execution of the task encounters an exception, subsequent executions are suppressed.

将 try-catch 块添加到您的 Tick runnable。