我正在创建一个应用程序，它应该在正确的时间根据日期显示通知。但是通知来得晚或者是在打开应用程序之后。我请求您帮助我，指出代码中的错误，并对其不正确的原因进行注解。
androidmanifest.xml:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.VIBRATE"/>
<uses-permission android:name="android.permission.SET_ALARM" />

<receiver
    android:name="com.zalj.schedule.MyNotifications.MyAlarm"
    android:enabled="true"
    android:exported="true"
    android:permission="android.permission.RECEIVE_BOOT_COMPLETED">
</receiver>

我按如下方式设置闹钟：

private static void setAlarm(
        Context context, 
        int id, 
        Action action){
            Calendar calendar = Calendar.getInstance();
            AlarmManager alarmManager = (AlarmManager) context.getSystemService(ALARM_SERVICE);

            calendar.set(Calendar.HOUR_OF_DAY, action.getStartHour());
            calendar.set(Calendar.MINUTE, action.getStartMinute());
            calendar.set(Calendar.SECOND, 0);

            Intent intent = new Intent(context, MyAlarm.class);

            //Устанавливаем команду
            intent.putExtra(
                    IntentHelper.COMMAND,
                    IntentHelper.COMMAND_NOTIFICATION_SetAlarm);

            //ChanelId
            intent.putExtra(
                    IntentHelper.CHANEL_ID,
                    CHANEL_ID_ACTION);

            //ChanelName
            intent.putExtra(
                    IntentHelper.CHANEL_NAME,
                    context.getString(R.string.Notification_chanelName_Action));

            //ID
            intent.putExtra(
                    IntentHelper.NOTIFICATION_ID,
                    NOTIFICATION_ID_ACTION);

            //Title
            intent.putExtra(
                    IntentHelper.NOTIFICATION_TITLE,
                    action.getTitle());

            //Message
            intent.putExtra(
                    IntentHelper.NOTIFICATION_MESSAGE,
                    action.getMessage());

            PendingIntent pIntent  =
            PendingIntent.getBroadcast(
                    context,
                    id,
                    intent,
                    PendingIntent.FLAG_UPDATE_CURRENT);

            //Set alarm
            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
                alarmManager.setAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pIntent);
            else
                alarmManager.setExact(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pIntent);
        }

myalarm类：

public class MyAlarm extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    int idCase = intent.getIntExtra(
            IntentHelper.COMMAND,
            IntentHelper.COMMAND_NOTIFICATION_UpdateAlarmToDay);

    switch (idCase){
        case IntentHelper.COMMAND_NOTIFICATION_SetAlarm:{
            showNotification(context ,intent);
        }break;

        case IntentHelper.COMMAND_NOTIFICATION_UpdateAlarmToDay:{
            updateAlarmsToNextDay(context, intent);
        }break;
    }
}

private void showNotification(Context context, Intent intent){
    NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);

    String title;
    String message;
    String chanelId;
    String chanelNameDiscipline;
    int notificationId;

    title = intent.getStringExtra(IntentHelper.NOTIFICATION_TITLE);
    message = intent.getStringExtra(IntentHelper.NOTIFICATION_MESSAGE);
    chanelId = intent.getStringExtra(IntentHelper.CHANEL_ID);
    chanelNameDiscipline = intent.getStringExtra(IntentHelper.CHANEL_NAME);
    notificationId = intent.getIntExtra(IntentHelper.NOTIFICATION_ID, 0);

    NotificationCompat.Builder notification = new NotificationCompat.Builder(context, chanelId);
    notification
            .setSmallIcon(R.drawable.discipline_notification)
            .setContentTitle(title)
            .setContentText(message)
            .setStyle(new NotificationCompat.BigTextStyle())
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setSound(NotificationHelper.getSound())
            .setVibrate(NotificationHelper.getVibrate(NotificationHelper.LONG_VIBRATE))
            .setAutoCancel(true);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
    {
        NotificationChannel nc =
                new NotificationChannel(
                        chanelId,
                        chanelNameAction,
                        NotificationManager.IMPORTANCE_DEFAULT);

        notificationManager.createNotificationChannel(nc);
    }

    notificationManager.notify(notificationId, notification.build());
}

private void updateAlarmsToNextDay(Context context, Intent intent){
    Action action;

    String name = intent.getStringExtra(IntentHelper.ACTIONS_NAME);

    if (name == null){
        SharedPreferences settings = context.getSharedPreferences(
                DataContract.MyAppSettings.LAST_VIEWED_ACTIONS,
                Context.MODE_PRIVATE);

        name = settings.getString(
                DataContract.MyAppSettings.LAST_ACTIONS,
                DataContract.MyAppSettings.NULL);
    }

    ScheduleBuilder scheduleBuilder = ScheduleBuilder.getInternalSchedule(context, name);
    schedule = scheduleBuilder.build();
    schedule.updateTimes(context);
    schedule.updateActions(context, Calendar.getInstance());

    MyDisciplineNotificationManager.updateAllAlarm(context, schedule);
}

}