Shutting down VM

[xxzj990]

When I call FlutterForegroundServicePlugin.startPeriodicTask,get the following error:

D/AndroidRuntime( 7848): Shutting down VM E/AndroidRuntime( 7848): FATAL EXCEPTION: main E/AndroidRuntime( 7848): Process: xxx, PID: 7848 E/AndroidRuntime( 7848): java.lang.RuntimeException: Unable to start service com.saywut.flutter_foreground_service_plugin.FlutterForegroundService@204d1b2 with Intent { act=START_FOREGROUND_TASK cmp=xxx/com.saywut.flutter_foreground_service_plugin.FlutterForegroundService }: java.lang.NullPointerException: Attempt to invoke interface method 'void io.flutter.plugin.common.BinaryMessenger.setMessageHandler(java.lang.String, io.flutter.plugin.common.BinaryMessenger$BinaryMessageHandler)' on a null object reference E/AndroidRuntime( 7848): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3057) E/AndroidRuntime( 7848): at android.app.ActivityThread.access$2200(ActivityThread.java:165) E/AndroidRuntime( 7848): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1467) E/AndroidRuntime( 7848): at android.os.Handler.dispatchMessage(Handler.java:102) E/AndroidRuntime( 7848): at android.os.Looper.loop(Looper.java:150) E/AndroidRuntime( 7848): at android.app.ActivityThread.main(ActivityThread.java:5546) E/AndroidRuntime( 7848): at java.lang.reflect.Method.invoke(Native Method) E/AndroidRuntime( 7848): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794) E/AndroidRuntime( 7848): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:684) E/AndroidRuntime( 7848): Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'void io.flutter.plugin.common.BinaryMessenger.setMessageHandler(java.lang.String, io.flutter.plugin.common.BinaryMessenger$BinaryMessageHandler)' on a null object reference E/AndroidRuntime( 7848): at io.flutter.plugin.common.MethodChannel.setMethodCallHandler(MethodChannel.java:119) E/AndroidRuntime( 7848): at com.saywut.flutter_foreground_service_plugin.FlutterForegroundServicePlugin.setupChannels(FlutterForegroundServicePlugin.java:45) E/AndroidRuntime( 7848): at com.saywut.flutter_foreground_service_plugin.FlutterForegroundServicePlugin.registerWith(FlutterForegroundServicePlugin.java:23) E/AndroidRuntime( 7848): at com.saywut.flutter_foreground_service_plugin.FlutterForegroundService.createFlutterEngineAndBackgroundChannel(FlutterForegroundService.java:220) E/AndroidRuntime( 7848): at com.saywut.flutter_foreground_service_plugin.FlutterForegroundService.onStartCommand(FlutterForegroundService.java:95) E/AndroidRuntime( 7848): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3040) E/AndroidRuntime( 7848): ... 8 more I/Process ( 7848): Sending signal. PID: 7848 SIG: 9

[SayWut]

what is your flutter?
what is your android version?

paste the code sample when the exception occurs

from what I see, it is happens when you try to start the service task but I need your code to understand why it happens

[xxzj990]

@SayWut thank you for your reply.

I don't know how it happened.I will directly copy your sample code to main.dart and report this problem.It may be related to a library I referenced.

At present, I have made the following changes to the library code, and the problem no longer occurs：

private void setupChannels(BinaryMessenger messenger, Context context)
  {
    if(messenger != null) {
        FlutterForegroundServiceChannelHandler handler = new FlutterForegroundServiceChannelHandler(context);

        methodChannel = new MethodChannel(messenger, FOREGROUND_CHANNEL_CHANNEL);
        methodChannel.setMethodCallHandler(handler);
    }
  }

flutter doctor:

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 1.22.5, on Microsoft Windows [Version 10.0.19041.572], locale zh-CN)

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[!] Android Studio (version 4.1.0)
    X Flutter plugin not installed; this adds Flutter specific functionality.
    X Dart plugin not installed; this adds Dart specific functionality.
[√] IntelliJ IDEA Ultimate Edition (version 2019.2)
[√] VS Code, 64-bit edition (version 1.47.0)
[√] Connected device (1 available)

! Doctor found issues in 1 category.

[SayWut]

@xxzj990 But if the messnger is null and we do your solution the channels between flutter and android will not astublish and nothing will work

[SayWut]

can you copy your code to here?

[Piero512]

I too have this problem. I'm not entirely sure why Flutter is calling it like it was a V1 embedding plugin, but it does now I guess.
I'm using Flutter 2.2.3 stable. I can't reproduce it on the example one, but the stack trace seems exactly the same. Maybe the plugin needs to be ServiceAware?