dropdown.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: FirstPage(),
    );
  }
}

class FirstPage extends StatefulWidget {
  const FirstPage({Key? key}) : super(key: key);

  @override
  State<FirstPage> createState() => _FirstPageState();
}

class _FirstPageState extends State<FirstPage> {
  List<String> items = [
    'Item 1',
    'Item 2',
    'Item 3',
    'Item 4',
    'Item 5',
  ];
  String dropdownValue = 'Item 1';

  @override
  Widget build(BuildContext context) {
    List<DropdownMenuItem<String>> menuItems = [];

    for (int i = 0; i < items.length; i++) {
      DropdownMenuItem<String> item = DropdownMenuItem(
        value: items[i],
        child: Text(items[i]),
      );
      menuItems.add(item);
    }

    return Scaffold(
      appBar: AppBar(
        title: const Text('Heading'),
      ),
      body: Row(
        children: [
          Container(
            color: Colors.red,
            child: DropdownButton<String>(
              value: dropdownValue,
              items: items.map((e) => DropdownMenuItem(value: e, child: Text(e))).toList(),
              onChanged: (String? data) {
                dropdownValue = data!;
                setState(() {});
              },
            ),
          ),
          ElevatedButton(
            onPressed: () {},
            child: const Text('Change State'),
          ),
        ],
      ),
    );
  }
}