Flutter get data from child widgets - flutter

Question

There is a signup section in My App with a main page and 3 widgets form inside it. form 1 and form 2 contain some TextFormField and on the last page, I get some pictures from the user. the user, enter data and click the next button on the main page, now should be validate entered data, and if the data was without any problem, finally send a request with the entered data to a server and step++ and go to the next form.
my question is how can I do this job and get child form data on the main page?

Answer 1

You can use callback function. eg void Function(String)
class MainScreen extends StatelessWidget {
const MainScreen({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Scaffold(
body: Column(
children: [
YourFormWidget(
onFirstNameChanged: (String firstName) {
print(firstName);
},
onLastNameChanged: (String lastName) {
print(lastName);
},
),
TextButton(
onPressed: () {},
child: Text("Submit"),
)
],
),
);
}
}
class YourFormWidget extends StatelessWidget {
const YourFormWidget({
Key? key,
required this.onFirstNameChanged,
required this.onLastNameChanged,
}) : super(key: key);
final void Function(String) onFirstNameChanged;
final void Function(String) onLastNameChanged;
#override
Widget build(BuildContext context) {
return Column(
children: [
TextField(onChanged: onFirstNameChanged),
TextField(onChanged: onFirstNameChanged),
],
);
}
}

Answer 2

This is called state management. https://flutter.dev/docs/development/data-and-backend/state-mgmt/options
I suggest provider. Create the object in the main page and update in one of it's children Widget.
An example with Provider https://flutter.dev/docs/development/data-and-backend/state-mgmt/simple