dropdown.dart

import 'package:flutter/material.dart';

void main() {
  runApp(
    const MaterialApp(
      title: 'Returning Data',
      home: HomeScreen(),
    ),
  );
}

class HomeScreen extends StatelessWidget {
  const HomeScreen({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Returning Data Demo'),
      ),
      body: Center(
        child: SummaryPayment(),
      ),
    );
  }
}

class SummaryPayment extends StatefulWidget {
  @override
  State<SummaryPayment> createState() => _SummaryPaymentState();
}

class _SummaryPaymentState extends State<SummaryPayment> {
  int index = 0;
  int _count = 1;
  String? dropdownvalue;
  Widget build(BuildContext context) {
    return DropdownButton<String>(
        value: dropdownvalue,
        items: <String>['A', 'B', 'C', 'D'].map((String value) {
          return DropdownMenuItem<String>(
            value: value,
            child: Text(value),
          );
        }).toList(),
        onChanged: (value) => setState(
              () => dropdownvalue = value,
            ));
  }
}