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android - 在活动销毁时保存 Countdowntimer 并在 onResume() 中恢复它

问题描述

我想启动一个计数器 2 分钟，当活动破坏时，我想保存它，在活动恢复时，我想在我离开的地方启动计数器

counter = new CountDownTimer(120000, 1000) { // adjust the milli seconds here

        public void onTick(long millisUntilFinished)
        {
            textview.setText("" + String.format("%d min, %d sec",
                    TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished),
                    TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) -
                            TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished))));

            Log.i(TAG, "onTick: "+millisUntilFinished);
        }

        public void onFinish()
        {
            textview.setText("done!");
        }
    }.start();

标签： androidcountercountdowntimer

解决方案

我们只是保存millisUntilFinished活动被销毁时的值，并CountDownTimer在活动再次启动时使用该值创建新的值。

long millisUntilFinished;

在onDestroy()（或onStop()）

@Override
    public void onDestroy() {
        SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
        editor.putLong("millisUntilFinished", millisUntilFinished);
        editor.apply();
        super.onDestroy();
    }

并获取millisUntilFinished您想要启动的时间CountDownTimer 

        SharedPreferences prefs = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE);
        millisUntilFinished = prefs.getLong("millisUntilFinished", 120000);

        counter = new CountDownTimer(millisUntilFinished, 1000) { // adjust the milli seconds here

            public void onTick(long millisUntilFinished) {
                this.millisUntilFinished = millisUntilFinished;
                textview.setText("" + String.format("%d min, %d sec",
                        TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished),
                        TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished)
                                - TimeUnit.MINUTES.toSeconds(
                                TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished))));

                Log.i(TAG, "onTick: " + millisUntilFinished);
            }

            public void onFinish() {
                textview.setText("done!");
            }
        }.start();

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