Flutter TextField value always null on ios device? - flutter

Question

I am currently testing my Flutter app on both my iPhone 8 and my Android moto G8.
However, the issue I am running into is that while everything works well on my Android moto G8, on my iPhone it seems that whenever I change a TextField the value in the previous TextField becomes null i.e.:
flutter: This is in error: 'package:firebase_auth/src/firebase_auth.dart': Failed assertion: line 174 pos 12: 'email != null': is not true.
But When I was typing on the device the printout is:
flutter: This is in email:test#gmail.com, value: test#gmail.com
Here is the code for my custom textfield:
class InputTextFields extends StatefulWidget {
InputTextFields({this.title, this.obscureText, this.setValue});
final String title;
final bool obscureText;
Function setValue;
final TextEditingController _controller = TextEditingController();
#override
_InputTextFieldsState createState() => _InputTextFieldsState();
}
class _InputTextFieldsState extends State<InputTextFields> {
#override
Widget build(BuildContext context) {
String hintText;
return Container(
padding: EdgeInsets.only(bottom: 10, left: 35, right: 35),
child: TextField(
obscureText: widget.obscureText,
decoration: InputDecoration(
labelText: widget.title,
labelStyle: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.bold,
color: Colors.grey),
focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Colors.grey,
),
),
hintText: hintText,
),
onChanged: widget.setValue,
),
);
}
}
So I am sure the TextField is working as intended but the error still persists. Any ideas how I can solve this?

Answer 1

The problem seems to be from your onChanged: widget.setValue in your TextField. Your function is making the previous TextField null. The best way to retrieve the value of a TextField is to use a TextEditingController. In order to use a TextEditingController in your custom TextField, you would have to pass it as a parameter.
class InputTextFields extends StatefulWidget {
InputTextFields({this.title, this.obscureText, this.controller});
final String title;
final bool obscureText;
final TextEditingController controller;
}
In your TextField:
controller:widget.controller
This is how you use that new custom TextField:
final TextEditingController myController=TextEditingController();
InputTextFields(title:"Test",obscureText:false,controller:myController),
I think you are trying to validate if the TextField's value is an email or not. You could easily check it by using RegExp or by using https://pub.dev/packages/email_validator package. You could also use TextFormField instead of TextField to check if the TextField's value is null. Have a look at this: https://flutter.dev/docs/cookbook/forms/validation. Good Luck!