ScheduledThreadPoolExecutor 仅“打勾"一次 [英] ScheduledThreadPoolExecutor only "ticking" once

问题描述

我使用 CountDownTimer 来实现我的 Activity 中的一些倒计时功能.我决定远离 CountDownTimer 并使用 ScheduledThreadPoolExecutor 因为 CountDownTimers 不能在 onTick() 中取消自己.

I was using a CountDownTimer for some countdown functionality I have in my Activity. I decided to move away from CountDownTimer and use ScheduledThreadPoolExecutor because CountDownTimers can't cancel themselves in onTick().

出于某种原因，我在以下代码中的 Runnable 只执行一次.我不确定为什么它不执行多次.destroyCountdownTimer() 函数没有被命中.

For some reason, my Runnable in the following code only executes once. I'm not sure why it isn't executing multiple times. The destroyCountdownTimer() function is not getting hit.

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;
    }
}

推荐答案

文档说:

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

将 try-catch 块添加到您的 Tick runnable.

Add try-catch block to your Tick runnable.

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