title: Firebase notifications not shown on foreground
body: <p>I'm trying to manage notifications, but I am not able to do nothing with them when app is in foreground.</p>
  
  <p>When app is minimified or completly closed, the notification is correctly shown, but if app is in foreground it is not seen.</p>
  
  <p>I have test variations of this code, but nothing works. The notifications with app closed or minimified works wit any modification of this code, or with any this code at all:</p>
  
  <p>(EDITED following comments indications, same result)</p>
  
  <pre><code>import android.app.Notification
  import android.app.NotificationManager
  import android.app.PendingIntent
  import android.content.Context
  import android.content.Intent
  import android.os.Looper
  import android.util.Log
  import androidx.appcompat.app.AlertDialog
  import androidx.core.app.NotificationCompat
  import com.google.firebase.messaging.FirebaseMessagingService
  import com.google.firebase.messaging.RemoteMessage
  import PACKAGE_NAME.ContenedorPrincipal
  import PACKAGE_NAME.R
  import PACKAGE_NAME.general.General
  import java.text.SimpleDateFormat
  import java.util.*
  //import java.util.concurrent.atomic.AtomicInteger
  
  class ServicioNotificaciones: FirebaseMessagingService()
  {
      //private val c = AtomicInteger(0)
  
      override fun onMessageReceived(remoteMessage: RemoteMessage) {
          super.onMessageReceived(remoteMessage)
  
          try{
              val uniqueID = Integer.parseInt(SimpleDateFormat("ddHHmmss",  Locale.getDefault()).format(Date()))
  
              val mNotificationManager: NotificationManager = applicationContext.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
  
              if(Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.O) {
                  val notificationChannel = NotificationChannel(
                      "notificationChannelID",
                      "notificationChannelName",
                      NotificationManager.IMPORTANCE_HIGH)
  
                  mNotificationManager.createNotificationChannel(notificationChannel)
              }
  
  
              val mBuilder: NotificationCompat.Builder = NotificationCompat.Builder(applicationContext, "notify_001")
              val ii = Intent(applicationContext, ContenedorPrincipal::class.java)
              val pendingIntent = PendingIntent.getActivity(applicationContext, 0, ii, 0)
  
              val bigText = NotificationCompat.BigTextStyle()
              bigText.bigText(remoteMessage.notification?.body ?: "")
              bigText.setBigContentTitle(remoteMessage.notification?.title ?: "")
              bigText.setSummaryText(remoteMessage.notification?.body ?: "")
  
              mBuilder.setContentIntent(pendingIntent)
              mBuilder.setSmallIcon(R.mipmap.ic_launcher_round)
              mBuilder.setContentTitle(remoteMessage.notification?.title ?: "")
              mBuilder.setContentText(remoteMessage.notification?.body ?: "")
              @Suppress("DEPRECATION")
              mBuilder.priority = Notification.PRIORITY_MAX
              mBuilder.setStyle(bigText)
  
              val buildedNotification = mBuilder.build()
  
              //mNotificationManager.notify(c.incrementAndGet(), buildedNotification)
              mNotificationManager.notify(uniqueID, buildedNotification)
  
              /*Looper.prepare()
              General.mostrarConfirmacion(
                  remoteMessage.notification?.title ?: "",
                  remoteMessage.notification?.body ?: "",
                  AlertDialog.Builder(this)
              )*/
          }
          catch (ex: Exception){
              Log.wtf("onMessageReceivedEX", ex.message.toString())
          }
      }
  }
  </code></pre>
  
  <p>And manifest:</p>
  
  <pre><code>   &lt;service
              android:name="PACKAGE_NAME.servicios.ServicioNotificaciones"
              android:enabled="true"
              android:exported="true"&gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="com.google.firebase.MESSAGING_EVENT" /&gt;
              &lt;/intent-filter&gt;
      &lt;/service&gt;
  </code></pre>
  
  <p>EDIT 2:
  I finnaly make it work with this code:</p>
  
  <pre><code>                val intent2 = Intent(this, MainActivity::class.java)
              intent2.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
              val pendingintent2 = PendingIntent.getActivity(this, 0, intent2, PendingIntent.FLAG_ONE_SHOT)
              val channelId = "Default"
              val builder = NotificationCompat.Builder(this, channelId)
                  .setSmallIcon(R.mipmap.ic_launcher)
                  .setContentTitle(remoteMessage.notification?.title)
                  .setContentText(remoteMessage.notification?.body).setAutoCancel(true)
                  .setContentIntent(pendingintent2)
              val manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
              if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.O) {
                  val channel = NotificationChannel(
                      channelId,
                      "Default channel",
                      NotificationManager.IMPORTANCE_DEFAULT
                  )
                  manager.createNotificationChannel(channel)
              }
              manager.notify(uniqueID, builder.build())
  </code></pre>
  
  <p>Thanks you all!</p>