ArgumentError（无效参数（onError）：Future.catchError 的错误处理程序必须返回未来类型的值）

Question

ArgumentError (Invalid argument(s) (onError): The error handler of Future.catchError must return a value of the future's type)

final User? firebaseUser = (
        await fAuth.signInWithEmailAndPassword(
        email: emailTextEditingController.text.trim(),
        password: passwordTextEditingController.text.trim()
        ).catchError((msg){
        
        Navigator.pop(context);
        Fluttertoast.showToast(msg: "Error" +msg.toString());
        })
        
        ).user;

       
  

Answer 1

Create async method to fetch user.

User? firebaseUser() async {
  return await fAuth
      .signInWithEmailAndPassword(
          email: emailTextEditingController.text.trim(),
          password: passwordTextEditingController.text.trim())
      .user;
}

you can show toast based on null user.

checkError() async {
  final user = await firebaseUser();

  if(user==null){
    //show message
  }
}