Flutter how to pass back data from model - flutter

Question

I'm practicing draggable widget. Thanks to amazing video by Tensor Programming. I was able to understand how things work.
However, there is one thing I'm not sure. Let's say if one of the DragBox tapped, I want to get text inside of the tapped DragBox. I wrapped Container with GestureDetector, but I have no idea how to make onTap function pass widget.label to AppState.
Should I use constructor or something to pass it?
Does anyone know hot to achieve this?
Thanks in advance.
import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: App(),
),
);
}
}
class App extends StatefulWidget {
#override
AppState createState() => AppState();
}
class AppState extends State<App> {
Color caughtColor = Colors.grey;
#override
Widget build(BuildContext context) {
return Stack(
children: <Widget>[
DragBox(Offset(0.0, 0.0), 'Box One', Colors.blueAccent),
DragBox(Offset(200.0, 0.0), 'Box Two', Colors.orange),
DragBox(Offset(300.0, 0.0), 'Box Three', Colors.lightGreen),
Positioned(
left: 100.0,
bottom: 0.0,
child: DragTarget(
onAccept: (Color color) {
caughtColor = color;
},
builder: (
BuildContext context,
List<dynamic> accepted,
List<dynamic> rejected,
) {
return Container(
width: 200.0,
height: 200.0,
decoration: BoxDecoration(
color: accepted.isEmpty ? caughtColor : Colors.grey.shade200,
),
child: Center(
child: Text("Drag Here!"),
),
);
},
),
)
],
);
}
}
class DragBox extends StatefulWidget {
final Offset initPos;
final String label;
final Color itemColor;
DragBox(this.initPos, this.label, this.itemColor);
#override
DragBoxState createState() => DragBoxState();
}
class DragBoxState extends State<DragBox> {
Offset position = Offset(0.0, 0.0);
#override
void initState() {
super.initState();
position = widget.initPos;
}
#override
Widget build(BuildContext context) {
return Positioned(
left: position.dx,
top: position.dy,
child: Draggable(
data: widget.itemColor,
child: GestureDetector(
onTap() {
// want to pass widget.label here
},
child: Container(
width: 100.0,
height: 100.0,
color: widget.itemColor,
child: Center(
child: Text(
widget.label,
style: TextStyle(
color: Colors.white,
decoration: TextDecoration.none,
fontSize: 20.0,
),
),
),
),
),
onDraggableCanceled: (velocity, offset) {
setState(() {
position = offset;
});
},
feedback: Container(
width: 120.0,
height: 120.0,
color: widget.itemColor.withOpacity(0.5),
child: Center(
child: Text(
widget.label,
style: TextStyle(
color: Colors.white,
decoration: TextDecoration.none,
fontSize: 18.0,
),
),
),
),
));
}
}

Answer 1

Can you please refer this answer. In the link
RootPage is similar to App,
AppState is similar to _RootPageState,
DragBox is similar to FeedPage and
DragBoxState is similar to _feedPageState
If it is not helpful, please comment, i can put example for your App