Java 运行API 27的仿真器上未显示Android通知

有人能帮我理解我做错了什么吗？我有一个Alarm Receiver对象，当我的三星Galaxy Tab 4上运行几年前获得的API 19触发通知时，它似乎可以工作。但是代码显然有一些bug，因为模拟器上从来没有触发过什么。我一直在读到，对于较新的API，创建NotificationChannel对象是必要的，但即使在我的代码中有了这个对象，我似乎也无法得到想要的结果

 class AlarmReceiver : BroadcastReceiver() {

        override fun onReceive(context: Context, intent: Intent) {
        val notificationIntent = Intent(context, NotificationActivity::class.java)

        val stackBuilder = TaskStackBuilder.create(context)
        stackBuilder.addParentStack(NotificationActivity::class.java)
        stackBuilder.addNextIntent(notificationIntent)

        val pendingIntent = stackBuilder.getPendingIntent(100, PendingIntent.FLAG_UPDATE_CURRENT)


        val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            var builder = NotificationCompat.Builder(context, "DailyJoke")

        if (android.os.Build.VERSION_CODES.O <= android.os.Build.VERSION.SDK_INT) {
            val importance = NotificationManager.IMPORTANCE_HIGH

            //Here's the notificationChannel object. It doesn't seem to work, idk why
            val notificationChannel = NotificationChannel("DailyJoke", "Name", importance)

            notificationManager.createNotificationChannel(notificationChannel)

            Builder(context, notificationChannel.id)
        } else {
            Builder(context)
        }


            val sound = Uri.parse("android.resource://" + context.packageName + "/" + "raw/drumroll")


            builder = builder
                    .setSmallIcon(R.mipmap.ic_launcher_round)
                    .setColor(Color.BLUE)
                    .setContentTitle("Content Title")
                    .setTicker("TICKER Text")
                    .setContentText("KDW setContentText")
                    .setAutoCancel(true)
                    .setContentIntent(pendingIntent)
                    .setChannelId("DailyJoke")
                    .setSound(sound)

                notificationManager.notify(1, builder!!.build())

    }
}

class AlarmReceiver:BroadcastReceiver（）{
覆盖接收（上下文：上下文，意图：意图）{
val notificationIntent=Intent（上下文，NotificationActivity:：class.java）
val stackBuilder=TaskStackBuilder.create（上下文）
addParentStack（NotificationActivity:：class.java）
stackBuilder.addNextIntent（notificationIntent）
val pendingent=stackBuilder.getpendingent（100，pendingent.FLAG_UPDATE_CURRENT）
val notificationManager=context.getSystemService（context.NOTIFICATION\u服务）作为notificationManager
var builder=NotificationCompat.builder（上下文，“DailyJoke”）
if（android.os.Build.VERSION_code.O