Cannot run example app from pub.dev

[BenShelbourne]

I am trying to run the example found here but when I run it I get the following error.

The following _CastError was thrown attaching to the render tree:
type '(MethodCall) => Null' is not a subtype of type '((MethodCall) => Future<dynamic>)?' in type cast

What is the fix for this?

[fxia86]

the same issue.

pubspec.yaml
environment:
sdk: ">=2.10.0 <3.0.0" works well

environment:
sdk: ">=2.12.0 <3.0.0" will throw the exception below

════════ Exception caught by widgets library ═══════════════════════════════════
The following _CastError was thrown building Builder:
type '(MethodCall) => Null' is not a subtype of type '((MethodCall) => Future<dynamic>)?' in type cast

The relevant error-causing widget was
GestureDetector
lib\main.dart:29
When the exception was thrown, this was the stack
#0      new BluetoothPrint._
package:bluetooth_print/bluetooth_print.dart:26
#1      BluetoothPrint._instance
package:bluetooth_print/bluetooth_print.dart:29
#2      BluetoothPrint._instance (package:bluetooth_print/bluetooth_print.dart)
package:bluetooth_print/bluetooth_print.dart:1
#3      BluetoothPrint.instance
package:bluetooth_print/bluetooth_print.dart:31
#4      new _PrinterManagePageState
package:bubble_tea/…/printer/printer_manage_page.dart:44
...
════════════════════════════════════════════════════════════════════════════════

[BenShelbourne]

@thon-ju are there any plans to migrate to 2.12 ?

[tranthanhvu]

I have to modify the constructor to fix it
From

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

To

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

environment:
sdk: ">=2.12.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
bluetooth_print: ^3.0.1