Flutter) I want to change screen in ModalBottomSheet... WHAT IS PROBLEM..? - flutter

Question

I made an int variable tab1 and a function addTab to control the screen in modalBottomSheet, and I thought that when TextButton in HandAdd1() is pressed, a function addTab is executed, and changes the int variable tab1.
In MyApp(), as a result HandAdd2() widget is shown according to the list in MyApp(), but int variable tab1 doesn't change no matter how many times I press the TextButton in HandAdd1(), so the screen doesn't change, and I don't know what the problem is.
Can you help me ?
Here's the code:
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
int tab1 = 0;
addTab (){
setState(() {
tab1++;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton:FloatingActionButton.extended(
onPressed: () {
showModalBottomSheet(
context: context,
builder: (BuildContext context) {
return Container(
padding:EdgeInsets.fromLTRB(20,30,20,20),
height:MediaQuery.of(context).size.height * 50,
margin: const EdgeInsets.only(
left: 0,
right: 0,
bottom: 0,
),
decoration: const BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topLeft:Radius.circular(25),
topRight: Radius.circular(25),
),
),
child: Scaffold(body:[HandAdd1(addTab:addTab) , HandAdd2()][tab1]),
);
},
backgroundColor: Colors.transparent,
);
);
}
}
and here's HandAdd1() WIdget. (HandAdd2() is almost similar to HandAdd1())
class HandAdd1 extends StatefulWidget {
const HandAdd1({Key? key, this.addTab}) : super(key: key);
final void addTab;
#override
HandAdd1State createState() => HandAdd1State();
}
class HandAdd1State extends State<HandAdd1> {
#override
Widget build(BuildContext context) {
return Column(
children:[
Align(alignment:Alignment.centerLeft, child:Padding(
padding:EdgeInsets.fromLTRB(0,20,0,0,),
child:Text('''title''' ,
),
),
),
Padding(
padding:EdgeInsets.fromLTRB(0,20,0,20,),
child:Container(),
),
InkWell(child: Container(
margin:EdgeInsets.fromLTRB(0,20,0,0,),
alignment:Alignment.center,
width: MediaQuery.of(context).size.width * 50,
height:60,
decoration: BoxDecoration(
borderRadius:BorderRadius.all(Radius.circular(10)),
color: Colors.pinkAccent,
),
child:Text('button' , style: TextStyle(color:Colors.white , fontWeight:FontWeight.w500 , fontSize: 20,))
),
onTap: (){
widget.addTab;
}
),
],
);
}
}

Answer 1

You need to pass addTab function to a addTab property as a VoidCallback.
In your HandAdd1 widget,
Change from final void addTab; to final VoidCallback addTab;
And from widget.addTab; to widget.addTab();