How we can control function from other page in flutter - flutter

Question

I make small app this app have two pages. First page main page then second page. now in each pages I add function this function to can add new data in MySQL database. Now my problem the user is work in main page and when click button add in main page I need to make the method on the other page work as well in same time.
So how we can control function from other page? How I can call AddNewColor() in MainPage in button (add new data).
Note: This is just an example of what I am trying to do also to understand the idea and the problem. In my full application, I display the second page on the first page to display a set of images.
Main page code:
void main() {
runApp(MainPage());
}
class MainPage extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MainPage> {
TextEditingController NameController = TextEditingController();
Future AddNewData() async {
final response = await http.post(Uri.parse("**********", ),
body: {
"Name": NameController.text,
}
);
if (response.statusCode == 200) {
} else {
throw Exception('Send Failed');
}
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: Column(children: [
TextFormField(
controller: NameController,
decoration: InputDecoration(
border: OutlineInputBorder(),
),
),
ElevatedButton(
child: Text('add new data'),
onPressed: () {
AddNewData();
},
),
],)
),
);
}
}
Second Page code:
class secondpage extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<secondpage> {
TextEditingController ColorController = TextEditingController();
Future AddNewColor() async {
final response = await http.post(Uri.parse("**********", ),
body: {
"Color": ColorController.text,
}
);
if (response.statusCode == 200) {
} else {
throw Exception('Send Failed');
}
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: Column(children: [
TextFormField(
controller: ColorController,
decoration: InputDecoration(
border: OutlineInputBorder(),
),
),
ElevatedButton(
child: Text('add new color'),
onPressed: () {
AddNewColor();
},
),
],)
),
);
}
}

Answer 1

Define AddNewColor() out of secondpage class:
Future AddNewColor(TextEditingController colorController) async {
final response = await http.post(Uri.parse("**********", ),
body: {
"Color": ColorController.text,
}
);
if (response.statusCode == 200) {
} else {
throw Exception('Send Failed');
}
}
class secondpage extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<secondpage> {
...
}
now you can call it every where you want. Note that use return way to pass the result data.
update:
try define ColorController here:
class _MyAppState extends State<MainPage> {
TextEditingController NameController = TextEditingController();
TextEditingController ColorController = TextEditingController();
Future AddNewData() async {
...
}
...
}
then change your second page to receive it like this:
class secondpage extends StatefulWidget {
final TextEditingController ColorController;
secondpage(this.ColorController);
#override
_MyAppState createState() => _MyAppState();
}
now you can use ColorController in both pages with AddNewColor.