Android：当应用程序关闭 30 秒时，通知会延迟显示并停止更新（在 OnePlus 8T 上）

谷歌有自己的时钟应用程序，其中包括秒表。我目前正在尝试在我的应用程序中创建一个（计数）计时器，或者您可以将其称为秒表，它将能够在后台运行，当它在后台运行时，我希望它也显示通知，显示计时时间和“停止”按钮（所有这些都发生在谷歌时钟应用程序中（see here https://stackoverflow.com/q/67028013/8099601））。对于我的应用程序中的计时器，我使用一个处理程序来发布一个 Runnable，它正在发布自己。我正在用 Java 编写我的应用程序。

定义“计时器”的代码（处理程序和可运行）：

Handler timerHandler = new Handler();
Runnable timerRunnable = new Runnable() {
    @Override
    public void run() {
        long millis = System.currentTimeMillis() - startTime;
        seconds = (millis / 1000) + PrefUtil.getTimerSecondsPassed();
        timerHandler.postDelayed(this, 500);
    }
};

我的 onPause 函数：

@Override
public void onPause() {
    super.onPause();

    if (timerState == TimerState.Running) {
        timerHandler.removeCallbacks(timerRunnable);
        //TODO: start background timer, show notification
    }

    PrefUtil.setTimerSecondsPassed(seconds);
    PrefUtil.setTimerState(timerState);
}

如何在我的应用程序中实现后台服务和通知？

Edit

我已成功创建运行计时器的前台服务，但有两个问题：

1. 当我在大约 5 分钟后运行应用程序时，通知会延迟 10 秒显示。
2. 通知在启动/恢复后大约 30 秒后停止更新（计时器在后台继续运行，但通知不会随计时器一起更新）。

这是我的Services code:

public class TimerService extends Service {

    Long startTime = 0L, seconds = 0L;
    boolean notificationJustStarted = true;
    Handler timerHandler = new Handler();
    Runnable timerRunnable;
    NotificationCompat.Builder timerNotificationBuilder = new NotificationCompat.Builder(this, CHANNEL_ID);
    public static final String TIMER_BROADCAST_ID = "TimerBroadcast";
    Intent timerBroadcastIntent = new Intent(TIMER_BROADCAST_ID);

    @Override
    public void onCreate() {
        Log.d(TAG, "onCreate: started service");
        startForeground(1, new NotificationCompat.Builder(this, CHANNEL_ID).setSmallIcon(R.drawable.timer).setContentTitle("Goal In Progress").build());
        super.onCreate();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        String goalName = intent.getStringExtra(PublicMethods.getAppContext().getString(R.string.timer_notification_service_current_goal_extra_name));
        startTime = System.currentTimeMillis();
        notificationJustStarted = true;
        timerRunnable = new Runnable() {
            @Override
            public void run() {
                long millis = System.currentTimeMillis() - startTime;
                seconds = (millis / 1000) + PrefUtil.getTimerSecondsPassed();
                updateNotification(goalName, seconds);
                timerHandler.postDelayed(this, 500);
            }
        };
        timerHandler.postDelayed(timerRunnable, 0);

        return START_STICKY;
    }

    public void updateNotification(String goalName, Long seconds) {
        try {
            if (notificationJustStarted) {
                Intent notificationIntent = new Intent(this, MainActivity.class);
                PendingIntent pendingIntent = PendingIntent.getActivity(this,
                        0, notificationIntent, PendingIntent.FLAG_IMMUTABLE);
                timerNotificationBuilder.setContentTitle("Goal In Progress")
                        .setOngoing(true)
                        .setSmallIcon(R.drawable.timer)
                        .setContentIntent(pendingIntent)
                        .setOnlyAlertOnce(true)
                        .setOngoing(true)
                        .setPriority(NotificationCompat.PRIORITY_MAX);
                notificationJustStarted = false;
            }

            timerNotificationBuilder.setContentText(goalName + " is in progress\nthis session's length: " + seconds);

            startForeground(1, timerNotificationBuilder.build());
        } catch (Exception e) {
            Log.d(TAG, "updateNotification: Couldn't display a notification, due to:");
            e.printStackTrace();
        }
    }

    @Override
    public void onDestroy() {
        timerHandler.removeCallbacks(timerRunnable);
        PrefUtil.setTimerSecondsPassed(seconds);
        super.onDestroy();
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

这是我在片段中启动它的方式：

private void startTimerService() {
        Intent serviceIntent = new Intent(getContext(), TimerService.class);
        serviceIntent.putExtra(getString(R.string.timer_notification_service_current_goal_extra_name), "*Current Goal Name Here*");
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            Objects.requireNonNull(getContext()).startForegroundService(serviceIntent);
        }
}

UPDATE

当我在谷歌像素模拟器上运行该应用程序时，我没有遇到列出的任何问题

如果您将递归替换为即使启用了电池限制，解决方案也会工作得更好postDelayed with scheduleAtFixedRate在你的TimerService inside onStartCommand功能。像这样的东西：

        TimerTask timerTaskNotify = new TimerTask() {
            @Override
            public void run() {
                // add a second to the counter
                seconds++;

                //update the notification with that second
                updateNotification(goalName, seconds);

                //Print the seconds
                Log.d("timerCount", seconds + "");

                //Save the seconds passed to shared preferences
                PrefUtil.setTimerSecondsPassed(TimerService.this,seconds);
            }
        };
        Timer timerNotify = new Timer();
        timerNotify.scheduleAtFixedRate(timerTaskNotify, 0, 1000);

附：如果您授予许可，我可以更新您的 git 存储库）