flutter - 重新启动设备后在flutter中调用方法

Question

我构建了一个待办事项列表应用程序，该应用程序应显示提醒任务的通知。为了能够将通知安排到截止日期的确切时间，我将通知数据从 flutter 传递到Kotlin，并显示来自广播接收器的通知。
在这里，我将通知数据发送给kotlin:

 await platform.invokeMethod('setNextNotification', {
      'tasksNames': tasksNames,
      'notificationsTimeInMillis': notificationsTimeInMillis
    });

这就是我在FlutterActivity中获取数据的方式:

private const val CHANNEL = "flutter.native/helper"

class MainActivity : FlutterActivity() {

companion object {
    const val TASKS_NAMES_EXTRA = "tasksNames"
    const val NOTIFICATIONS_TIME_IN_MILLIS_EXTRA = "notificationsTimeInMillis"

}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    GeneratedPluginRegistrant.registerWith(this)

    // Init the AlarmManager.
    val alarmManager = getSystemService(Context.ALARM_SERVICE) as AlarmManager

    // We got here from the setNotifications() method in flutter...
    MethodChannel(flutterView, CHANNEL).setMethodCallHandler { call, result ->
        if (call.method == "setNextNotification") {

            // Get the time till next notification
            val notificationsTimeInMillis: ArrayList<Long> = call.argument(NOTIFICATIONS_TIME_IN_MILLIS_EXTRA)
                    ?: ArrayList()

            // Create a pending intent for the notifications
            val pIntent: PendingIntent? = createPendingIntent(call.argument(TASKS_NAMES_EXTRA), call.argument(TIME_LEFT_TEXTS_EXTRA), notificationsTimeInMillis, this)

            // Cancel all alarms
            while (alarmManager.nextAlarmClock != null)
                alarmManager.cancel(alarmManager.nextAlarmClock.showIntent)

            // Set the alarm
            setAlarm(notificationsTimeInMillis[0], pIntent, alarmManager)

        } 
    }
}

private fun setAlarm(notificationTime: Long, pIntent: PendingIntent?, alarmManager: AlarmManager) {

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { // The API is 23 or higher...
        alarmManager.setAlarmClock(AlarmManager.AlarmClockInfo(notificationTime, pIntent), pIntent)
    } else { // The API is 19 - 22...
        // We want the alarm to go of on the exact time it scheduled for so we use the setExact method.
        alarmManager.setExact(AlarmManager.RTC_WAKEUP, notificationTime, pIntent)
    }

}

private fun createPendingIntent(tasksNames: ArrayList<String>?, timeTillNotificationsInMillis: ArrayList<Long>?,
                                context: Context): android.app.PendingIntent? {

  
    return try {

        val intent: android.content.Intent = android.content.Intent(context, AlarmManagerHelperWakeful::class.java)
        intent.action = "notification"
     
        intent.putStringArrayListExtra(TASKS_NAMES_EXTRA, tasksNames)
        intent.putStringArrayListExtra(NOTIFICATIONS_TIME_IN_MILLIS_EXTRA, timeTillNotificationsInMillisAsString)
        android.app.PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
    } catch (e: java.lang.Exception) {
        null
    }
}

}
这就是我在BroadcastReceiver上显示通知的方式，然后设置下一个通知:

Class AlarmManagerHelperWakeful : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {

    if (intent != null && intent.action == "notification" && context != null) {
        
       
        val tasksLabels: ArrayList<String> = intent.getStringArrayListExtra(MainActivity.TASKS_NAMES_EXTRA)
                ?: ArrayList()

        val notificationsTimeInMillisAsString: ArrayList<String> = intent.getStringArrayListExtra(MainActivity.NOTIFICATIONS_TIME_IN_MILLIS_EXTRA)
                ?: ArrayList()

        if (tasksLabels.size > 0) {
          
            // Create a notification manager.
            val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            var builder = NotificationCompat.Builder(context) // The initialization is for api 25 or lower so it is deprecated.


            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { // This is API 26 or higher...
                // Create a channel for API 26 or higher;
                val channelId = "channel_01" // The id of the channel.
                if (notificationManager.getNotificationChannel(channelId) == null) {
                    val channel = NotificationChannel(channelId,
                            context.getString(R.string.notification_channel_name),
                            NotificationManager.IMPORTANCE_DEFAULT)
                    notificationManager.createNotificationChannel(channel)

                }
                // Update the builder to a no deprecated one.
                builder = NotificationCompat.Builder(context, channelId)
            }

            // Set the notification details.
            builder.setSmallIcon(android.R.drawable.ic_notification_overlay)
            builder.setContentTitle(tasksLabels[0])
            builder.setContentText(someText)
            builder.priority = NotificationCompat.PRIORITY_DEFAULT

            notificationId = someUniqueId

            // Show the notification.
            notificationManager.notify(notificationId.toInt(), builder.build())

            // Remove this notification from the notifications lists.
            tasksLabels.removeAt(0)
            notificationsTimeInMillisAsString.removeAt(0)

            // There are more notifications...
            if (tasksLabels.size > 0) {

                // Init the AlarmManager.
                val alarmManager = context.getSystemService(Context.ALARM_SERVICE) as AlarmManager

                // Cancel all alarms
                while (alarmManager.nextAlarmClock != null)
                    alarmManager.cancel(alarmManager.nextAlarmClock.showIntent)

                // Create a pending intent for the notifications
                val pIntent: PendingIntent? = createPendingIntent(tasksLabels, cnotificationsTimeInMillisAsString, context)

                // Set the alarm
                setAlarm(notificationsTimeInMillisAsString[0].toLong(), pIntent, alarmManager)

            }

        }

    } else {
        if (intent == null) {
            Log.d("Debug", "Checking: intent == null")
        } else if ( intent.action != "notification") {
            Log.d("Debug", "Checking: intent.action != notification")
            val tasksLabels: ArrayList<String> = intent.getStringArrayListExtra(MainActivity.TASKS_NAMES_EXTRA)
                    ?: ArrayList()
            Log.d("Debug", "Checking: tasksNames.size inside else if" + tasksLabels.size)
        }
    }

}
}

除非我重新启动设备，否则一切正常。然后，广播接收器得到了没有任何数据的意图。为了让BoradcastReceiver能够接收通知数据，我需要从flutter代码中调用该方法(将通知数据发送到kotlin代码的方法)，这意味着现在用户必须为此输入应用程序。否则，用户只有进入我的应用程序并重新调用 flutter 代码，才能看到通知。
我该如何克服这个问题？

Answer 1

您应该使用“推送通知”，而不是将本地通知发送到广播接收器。在很多情况下，您的应用无法发送本地通知。例如:用户关闭了应用程序(使用后用户总是关闭应用程序)，操作系统关闭了应用程序或清除了内存，Dart方法崩溃了。
Firebase FCM非常简单，比使用广播接收器的解决方案简单得多。也完全免费。
https://pub.dev/packages/firebase_messaging
Pushwoosh也很好，它有时间表通知
https://pub.dev/packages/pushwoosh
使用推送通知还具有其他优点，即您的应用程序也可以在iOS上运行，不需要让您的应用程序在后台运行，如果您的应用程序没有任何需要在后台运行的特殊功能(音乐播放器)，则是个坏主意，地理位置，VOIP)
如果您不想使用推送通知。看一下这个库:
https://pub.dev/packages/flutter_local_notifications