Flutter Access child function from its grand parent - flutter

Question

In my e-commerce admin cpanel app
I have a very big form (product form) with lots of section one for title and description and price, one for sale one for colors and seizes and images etc.
I divided it into smaller widget in separated classes and each of them has its own children widgets in another separated classes
each child class has a ( onSave ) function which I need to trigger from the main form button located in the grand grand parent so how can I access all ( onSave ) functions from this parent
In this ( onSave ) functions I'm using provider pattern to pass the data I collect in each widget to a provider class and in there I can send the datd to the server

Answer 1

You can use the Form() widget and place your input fields in it as children. then you define a GlobalKey() and pass it to the form's key property. once you call the save method on the GlobalKey, all children widgets onSaved function will be called.
e.g.
import 'package:flutter/material.dart';
class MyScreen extends StatefulWidget {
#override
_MyScreenState createState() => _MyScreenState();
}
class _MyScreenState extends State<MyScreen> {
final _formKey = GlobalKey<FormState>();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
children: [
Form(
key: _formKey,
child: Column(
children: [
TextFormField(
decoration: InputDecoration(labelText: "Name"),
onSaved: (name) {
// do stuff
},
),
TextFormField(
decoration: InputDecoration(labelText: "Category"),
onSaved: (category) {
// do stuff
},
),
],
)),
ElevatedButton(
onPressed: () {
_formKey.currentState.save();
},
child: Text("pressme"),
)
],
),
),
);
}
}