收到通知时打开后台活动

Question

我必须在收到推送通知时打开我的特定活动。当应用程序在前台时，我可以处理相同的操作，但是当应用程序在后台或被终止时，活动不显示。

我的通知帮助程序类

package com.oxicodes.apple.edropsStaff.firebaseservice

import android.app.Notification
import android.app.PendingIntent
import android.content.Context
import android.content.Intent
import android.media.MediaPlayer
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat

import com.oxicodes.apple.edropsStaff.Activity_pendingorders
import com.oxicodes.apple.edropsStaff.MainActivity
import com.oxicodes.apple.edropsStaff.R
import java.util.*


object NotificationHelper {
var pendingIntent: PendingIntent? = null
fun displayNotification(context: Context, title: String, body: String, notId: Int, foreground: Boolean) {

    if (title.equals("New Order")) {
        val random = Random().nextInt(1000).toString()

        val mBuilder = NotificationCompat.Builder(context, MainActivity.CHANNEL_ID)
                .setSmallIcon(R.drawable.ic_waterlogo)
                .setContentTitle(title)
                .setContentText(body)
                .setStyle(NotificationCompat.BigTextStyle()
                        .bigText(body))
                .setAutoCancel(true)
                .setPriority(NotificationCompat.PRIORITY_HIGH)
                .setDefaults(Notification.FLAG_ONLY_ALERT_ONCE)
        val mNotificationMgr = NotificationManagerCompat.from(context)
        val mp: MediaPlayer = MediaPlayer.create(context, R.raw.notificationb)
        mp.start()
        mNotificationMgr.notify(notId, mBuilder.build())
        if (foreground) { //app in foreground
            var intent = Intent(context, Activity_pendingorders::class.java)
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP or Intent.FLAG_ACTIVITY_CLEAR_TASK)
            pendingIntent = PendingIntent.getActivity(context, Integer.valueOf(random) /* Request code */, intent, PendingIntent.FLAG_UPDATE_CURRENT)
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
            context.startActivity(intent)      // to directly open activity if app is foreground
        }

    } else {
        val intent = Intent(context, MainActivity::class.java)
        val pendingIntent = PendingIntent.getActivity(
                context,
                100,
                intent,
                PendingIntent.FLAG_CANCEL_CURRENT
        )
        val mBuilder = NotificationCompat.Builder(context, MainActivity.CHANNEL_ID)
                .setSmallIcon(R.drawable.ic_waterlogo)
                .setContentTitle(title)
                .setContentText(body)
                .setStyle(NotificationCompat.BigTextStyle()
                        .bigText(body))
                .setContentIntent(pendingIntent)
                .setAutoCancel(true)
                .setPriority(NotificationCompat.PRIORITY_HIGH)
                .setDefaults(Notification.FLAG_ONLY_ALERT_ONCE)
        val mNotificationMgr = NotificationManagerCompat.from(context)
        val mp: MediaPlayer = MediaPlayer.create(context, R.raw.notification)
        mp.start()
        mNotificationMgr.notify(notId, mBuilder.build())

    }

}
}

我的Firebase消息服务类

class myfirebasemessaging : FirebaseMessagingService() {

override fun onMessageReceived(remoteMessage: RemoteMessage?) {
    super.onMessageReceived(remoteMessage)
    if (remoteMessage!!.data != null) {
        val title = remoteMessage.data!!.get("title")
        val body = remoteMessage.data!!.get("body")
        val tag = remoteMessage.data!!.get("notId")!!.toInt()
        var foreground = false

        try {
            foreground = ForegroundCheckTask().execute(this).get()
        } catch (e: InterruptedException) {
            e.printStackTrace()
        } catch (e: ExecutionException) {
            e.printStackTrace()
        }
        NotificationHelper.displayNotification(applicationContext, title!!, body!!, tag,foreground)
        if (!foreground){

            val random = Random().nextInt(1000).toString()
            var intent = Intent(this, Activity_pendingorders::class.java)
            
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP or Intent.FLAG_ACTIVITY_CLEAR_TASK )
            NotificationHelper.pendingIntent = PendingIntent.getActivity(this, Integer.valueOf(random) /* Request code */, intent, PendingIntent.FLAG_UPDATE_CURRENT)
            NotificationHelper.pendingIntent!!.send(this,0,intent)
        }
    }
}
private inner class ForegroundCheckTask : AsyncTask<Context, Void, Boolean>() {
    override fun doInBackground(vararg p0: Context?): Boolean {

        val context = p0[0]!!.applicationContext
        return isAppOnForeground(context)
    }

    private fun isAppOnForeground(context: Context): Boolean {
        val activityManager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
        val appProcesses = activityManager.runningAppProcesses ?: return false
        val packageName = context.packageName
        for (appProcess in appProcesses) {
            if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND && appProcess.processName == packageName) {
                return true
            }
        }
        return false
    }
}
}

我认为我错过了一些事情，请帮助我解决这个问题。