在android 8.0.0+中关闭应用程序后，如何在房间数据更改时通知用户？

Question

我正在做一个小任务工，现在遇到了通知问题。我的应用程序将一些任务存储在其内部存储（room db）中。我需要任务处理程序在任务的截止日期结束时通知用户，即使该应用程序已关闭。我已经发出通知，通知将在截止日期结束并且活动仍在打开时弹出。.但是我不知道在关闭我的应用程序时该如何做。这是一些代码：

// NotificationUtil.kt

fun NotificationManager.sendNotification(messageBody: String, applicationContext: Context) {
    val contentIntent = Intent(applicationContext, MainActivity::class.java)
    val contentPendingIntent = PendingIntent.getActivity(
        applicationContext,
        NOTIFICATION_ID,
        contentIntent,
        PendingIntent.FLAG_UPDATE_CURRENT
    )

    val builder = NotificationCompat.Builder(
        applicationContext,
        applicationContext.getString(R.string.task_notification_channel_id)
    )
        .setSmallIcon(R.drawable.icon)
        .setContentTitle(applicationContext.getString(R.string.notification_title))
        .setContentText(messageBody)
        .setContentIntent(contentPendingIntent)
        .setAutoCancel(true)

    notify(NOTIFICATION_ID, builder.build())
}

// code which refers to this theme from MainFragment(MainActivity)

listViewModel.tasks.observe(viewLifecycleOwner, Observer {
    it.forEach {
        if (it.date.isBefore(LocalDate.now()) && it.date != LocalDate.MIN && it.stage == 0) {
            val notificationManager = ContextCompat.getSystemService(
                application,
                NotificationManager::class.java
            ) as NotificationManager
            notificationManager.sendNotification(application
                .getString(R.string.you_missed_the_deadline), application)
        }
    }
})

fun createChannel(channelId: String, channelName: String) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        val notificationChannel = NotificationChannel(
            channelId,
            channelName,
            NotificationManager.IMPORTANCE_DEFAULT).apply {
                setShowBadge(false)
            }

        notificationChannel.enableLights(true)
        notificationChannel.lightColor = Color.BLUE
        notificationChannel.enableVibration(true)
        notificationChannel.description =
            getString(R.string.task_notification_channel_description)

        val notificationManager = requireActivity().getSystemService(
            NotificationManager::class.java)
        notificationManager.createNotificationChannel(notificationChannel)
    }
}

createChannel(
    getString(R.string.task_notification_channel_id),
    getString(R.string.task_notification_channel_name)
)

// Entity, if needed

@Entity(tableName = "tasks_table")
@TypeConverters(Converters::class)
data class Task(
    @PrimaryKey(autoGenerate = true)
    var taskId: Long,

    @ColumnInfo(name = "task_title")
    var title: String,

    @ColumnInfo(name = "task_details")
    var details: String,

    @ColumnInfo(name = "task_date")
    var date: LocalDate = LocalDate.MIN,

    @ColumnInfo(name = "task_stage")
    var stage: Int = 0
)

提前谢谢！