(MethodCall) => Null' is not a subtype of type '((MethodCall) => Future<dynamic>)?'

[zeed-dev]

════════ Exception caught by widgets library ═══════════════════════════════════ type '(MethodCall) => Null' is not a subtype of type '((MethodCall) => Future)?' in type cast The relevant error-causing widget was

STUCK IN THIS issue please help.

[22syamsudar]

same with... :(

[zeed-dev]

To fix it, replace default constructor in 34 line of blue_thermal_printer.dart from this:

  BlueThermalPrinter._() {
    _channel.setMethodCallHandler((MethodCall call) {
      _methodStreamController.add(call);
    } as Future<dynamic> Function(MethodCall)?);
  }

to this:

BlueThermalPrinter._() {
    _channel.setMethodCallHandler((MethodCall call) async{
      _methodStreamController.add(call);
    });
  }