I need to create a shared component but this error appears

<The argument type 'Function?' can't be assigned to the parameter type 'void Function(String)?>

although I changed Function type into VoidCallback type but it didn't work, please help

Widget defaultFormField({
       required TextEditingController controller,
       required String label,
       required TextInputType type,
       required VoidCallback validate,
       Function? onSubmit,
       required IconData prefix}) => 
       onFieldSubmitted: onSubmit,
       validator: validate,
       controller: controller,
       keyboardType: type,    
);

CodePudding user response：

You need to pass onSubmit as Function(String)?. Try this:

Widget defaultFormField({
       required TextEditingController controller,
       required String label,
       required TextInputType type,
       required VoidCallback validate,
       Function(String)? onSubmit,
       required IconData prefix}) => 
       onFieldSubmitted: onSubmit,
       validator: validate,
       controller: controller,
       keyboardType: type,    
);

CodePudding user response：

Change Function? into Function(String)?