.Net Maui app crashes when using sbn.PackageName in OnNotificationPosted() when implementing NotificationListenerService

Question

Have implemented NotificationListenerService in my app as below, if I use sbn.PackageName (commented below) app crashes. It appears to be a .Net MAUI bug, because while developing the same in Java it(sbn.getPackageName()) seem to work fine . In order to see which Package the notification is targeted to, I have to identify this info from the received notification, appreciate any help in this regard. EDIT : Further trouble shooting realized that this "PackageName" works fine in Emulator, but when deploying in real device (tested in 2 devices Redmi Note 5 pro and 10i) app crashes upon opening itself.

[Service(Label = "ServiceName", Permission = "android.permission.BIND_NOTIFICATION_LISTENER_SERVICE")]  
   [IntentFilter(new[] { "android.service.notification.NotificationListenerService" })]  
   public class NLService : NotificationListenerService  
   {  
       public override void OnCreate()  
       {  
           base.OnCreate();  
           Log.Info("start running", "Servico Criado");  
       }  
       public override void OnDestroy()  
       {  
           base.OnDestroy();  
       }  
       public override IBinder OnBind(Intent intent)  
       {  
           return base.OnBind(intent);  
       }  
       public override bool OnUnbind(Intent intent)  
       {  
           return base.OnUnbind(intent);  
       }  
       public override void OnNotificationPosted(StatusBarNotification sbn)  
       {  
         var  notification= sbn.Notification;  
           Bundle extras = notification.Extras; 

           // if below line is uncommented, APP will CRASH
           // if(sbn.PackageName == "com.xyzapp"){ //Do Something }

           if (extras != null)  
           {  
               // Get the title from notification  
               string title = extras.GetString(Notification.ExtraText, "");  

               // Get the content from notification  
               string content = extras.GetString(Notification.ExtraText, "");  
               Console.WriteLine("============" + content + "======================");  
           }  



           base.OnNotificationPosted(sbn);  
       }  

       public override void OnNotificationRemoved(StatusBarNotification sbn)  
       {  
           base.OnNotificationRemoved(sbn);  
       }  
   }

Below is first few lines of error report

backtrace:
    #00 pc 000000000002216c  /system/lib64/libc.so (abort+116)
    #01 pc 0000000000039f1c  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonodroid.so (xamarin::android::internal::MonodroidRuntime::mono_log_handler(char const*, char const*, char const*, int, void*)+144)
    #02 pc 00000000002da9a8  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonosgen-2.0.so
    #03 pc 00000000002daad4  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonosgen-2.0.so
    #04 pc 00000000002dab18  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonosgen-2.0.so
    #05 pc 00000000000df8a8  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonosgen-2.0.so
    #06 pc 0000000000113c0c  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonosgen-2.0.so (mono_method_get_unmanaged_callers_only_ftnptr+60)
    #07 pc 0000000000026108  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonodroid.so (xamarin::android::internal::MonodroidRuntime::init_android_runtime(_JNIEnv*, _jclass*, _jobject*)+1320)
    #08 pc 0000000000027bac  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonodroid.so (xamarin::android::internal::MonodroidRuntime::create_and_initialize_domain(_JNIEnv*, _jclass*, xamarin::android::jstring_array_wrapper&, xamarin::android::jstring_array_wrapper&, _jobjectArray*, xamarin::android::jstring_array_wrapper&, _jobject*, bool, bool, bool)+160)
    #09 pc 000000000002b0f4  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonodroid.so (xamarin::android::internal::MonodroidRuntime::Java_mono_android_Runtime_initInternal(_JNIEnv*, _jclass*, _jstring*, _jobjectArray*, _jstring*, _jobjectArray*, int, _jobject*, _jobjectArray*, int, unsigned char, unsigned char)+4116)
    #10 pc 000000000002e5e4  /data/app/com.companyname.wmoni-AciNshhqc0_S-X8oLMzwAw==/lib/arm64/libmonodroid.so (Java_mono_android_Runtime_initInternal+88)

Answer 1

When you implemented NotificationListenerService, please check if the service has been enabled at first.

And I used the following code to go to the Notification settings to check if the app has been granted by the permission.

Platform.CurrentActivity.StartActivity(
     new Android.Content.Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS"));

In addition, starting from the Android 12.0, the component with intent filter need to declare the exported attribute. So you can declare it for the service:

[Service(Exported = True ,Label = "ServiceName", Permission = "android.permission.BIND_NOTIFICATION_LISTENER_SERVICE")]  

After this, the NotificationListenerService worked for me.

The result image: