Flutter basic app

flutter_basic_app.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyMainApp());
}

class MyMainApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home:_MyApp() 
    );
  }
}

class _MyApp extends StatefulWidget {

 @override
 _MyAppState createState()=> new _MyAppState(); 
}


class _MyAppState extends State<_MyApp> {
  
  final questions = [
    {"question":"whats your favourite color?",
     "answers":["Red","Green","Blue"]
    },
  
    {"question":"whats your favourite guy?",
     "answers":["Myself","Eren","Ozgur"]
    }
   ];
  
  int _counter = 0;
  
 incrementCounter(){
   setState(()=>_counter++);
 }
 
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title:Text("Quiz Sample") , actions: [ new Icon(Icons.refresh) ], ),
        body: Center(
          child: Column(
          children: [
            Text(questions[_counter]["question"] as String)
          
          ],
          ),
        ),//end of body
       floatingActionButton: MyFloatingActionButton(text: "+",pressHandler: incrementCounter),
      );
  }
}

class MyFloatingActionButton extends  StatelessWidget{
  
  final String text;
  final void Function() pressHandler;
  
  MyFloatingActionButton({required this.text,required this.pressHandler});
  
    @override
  Widget build(BuildContext context) 
  {
    return FloatingActionButton( onPressed: this.pressHandler,
                                 child: Icon(Icons.check_circle)
                                  );
  }
  
}