android_alarm_manager_plus 1.2.0 Unhandled Exception

[spacekestrel]

Upon adding this line:

 await AndroidAlarmManager.initialize();

flutter gives this message:

E/flutter ( 3632): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Null check operator used on a null value
E/flutter ( 3632): #0      MethodChannel.binaryMessenger
package:flutter/…/services/platform_channel.dart:121
E/flutter ( 3632): #1      MethodChannel._invokeMethod
package:flutter/…/services/platform_channel.dart:146
E/flutter ( 3632): #2      MethodChannel.invokeMethod
package:flutter/…/services/platform_channel.dart:329
E/flutter ( 3632): #3      AndroidAlarmManager.initialize
package:android_alarm_manager_plus/android_alarm_manager_plus.dart:99
E/flutter ( 3632): #4      main
package:test_alarm/main.dart:6
E/flutter ( 3632): #5      _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:145:25)
E/flutter ( 3632): #6      _rootRun (dart:async/zone.dart:1428:13)
E/flutter ( 3632): #7      _CustomZone.run (dart:async/zone.dart:1328:19)
E/flutter ( 3632): #8      _runZoned (dart:async/zone.dart:1863:10)
E/flutter ( 3632): #9      runZonedGuarded (dart:async/zone.dart:1851:12)
E/flutter ( 3632): #10     _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:141:5)
E/flutter ( 3632): #11     _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:283:19)
E/flutter ( 3632): #12     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)
E/flutter ( 3632):

[JamiuJimoh]

Can I work on this? @mhadaily

[ScottishRoss]

@mhadaily I may have a solution for this. There was another issue that I can no longer find that was related to this. All I need is some advice on how to set get everything set up so I can package the PR together.

[mhadaily]

@JamiuJimoh and @ScottishRoss can you both work on this and see if you have a similar solution ? you may continue here in the comments.

[JamiuJimoh]

Alright. @ScottishRoss let's do this

[ScottishRoss]

@JamiuJimoh Awesome! So what I did is I made all instances of BinaryMessenger nullable, then in platform_channel.dart (line 150) I modified _invokeMethod to check if binaryMessenger is null:

Future<T?> _invokeMethod<T>(String method,
      {required bool missingOk, dynamic arguments}) async {
    assert(method != null);
    if (binaryMessenger != null) {
      final ByteData? result = await binaryMessenger!.send(
        name,
        codec.encodeMethodCall(MethodCall(method, arguments)),
      );
      if (result == null) {
        if (missingOk) {
          return null;
        }
        throw MissingPluginException(
            'No implementation found for method $method on channel $name');
      }
      return codec.decodeEnvelope(result) as T?;
    }
  }

I'm not too sure of this solution, truthfully. But it appears BinaryMessenger can be null at the start, which is why this is happening.

Another solution was to add WidgetsFlutterBinding.ensureInitialized(); to the start of my main().

[JamiuJimoh]

@ScottishRoss i'm sorry for the late reply. I just got everything setup on my PC. I can't find the platform_channel.dart file.

[ScottishRoss]

@JamiuJimoh Yeah, it's a Flutter file, so let's not do that! My bad.

[JamiuJimoh]

Alright. I'll keep on debugging. I'll let you know when I find something. I'm checking where the error is coming from and then i'll check what's causing it.