postDelayed和removeCallbacks无法按预期工作

Question

我正在开发一款带有开始按钮的秒表应用程序。单击开始按钮后，计时器启动，按钮文本更新为暂停。单击“暂停”后，计时器停止，按钮文本更改为“恢复”。当我点击继续时，我希望计时器从它暂停的位置开始，但是计时器会向前跳几秒钟。以下是代码段：

    @Override
        protected void onCreate(Bundle savedInstanceState) {
    this.timerHandler = new Handler();
    startButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    if(!MainActivity.running && !MainActivity.paused) {
                        MainActivity.running = true;
                        MainActivity.paused = false;
                        MainActivity.startTime = System.currentTimeMillis();
                        startTimer();
                        startButton.setText("PAUSE");
                    }
                    else if (MainActivity.running && !MainActivity.paused) {
                        MainActivity.running = false;
                        stopTimer();
                        MainActivity.paused = true;
                        MainActivity.pauseTime = System.currentTimeMillis();
                        MainActivity.pauseTimerText = timerText(); // Eg: 00:00:08
                        startButton.setText("RESUME");
                    }
                    else if(MainActivity.paused) {
                        MainActivity.running = true;
                        MainActivity.paused = false;
                        startTimer();
                        startButton.setText("PAUSE");
                    }

                    resetButton.setVisibility(View.VISIBLE);
                }
            });
    }


Runnable timerRunnable = new Runnable() {
        @Override
        public void run() {
            if (!MainActivity.running) {
                return;
            }
            if (pauseTimerText != null)
            {
                MainActivity.timerTV.setText(pauseTimerText); // this gets set to 00:00:08 here
                pauseTimerText = null;
            }
            else
            {
                MainActivity.timerTV.setText(timerText());
            }
            timerHandler.postDelayed(timerRunnable, 100); // this changes the timer text.
        }
    };

    void startTimer() {
        MainActivity.running = true;
        timerRunnable.run();
    }

    void stopTimer() {
        MainActivity.running = false;
        timerHandler.removeCallbacks(timerRunnable);
        timerHandler.removeCallbacksAndMessages(null);
    }

如果我的pauseTimerText是00:00:08，那么在runnable＆＃34; MainActivity.timerTV.setText（pauseTimerText）;＆＃34; line确实将计时器文本设置为00:00:08，但我注意到在postDelayed执行后，而不是在UI上显示00:00:08的计时器，它会显示类似于00:00:13，即它也会加起来显示暂停的时间。

看起来postDelayed无法正常工作或者removeCallBacks没有删除所有内容。