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dropdown_example.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Car _selectedCar;
  List<Car> _cars;

  @override
  void initState() {
    super.initState();

    _cars = Car.getCars();
    _selectedCar = _cars.first;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(child: getDropDown()));
  }

  Widget getDropDown() {
    var items = _cars.map((car) {
      return new DropdownMenuItem<Car>(
        value: car,
        child: new Text(
          car.make,
          style: new TextStyle(color: Colors.black),
        ),
      );
    }).toList();

    return DropdownButton<Car>(
      value: this._selectedCar,
      onChanged: (Car car) {
        setState(() {
          this._selectedCar = car;
        });
      },
      items: items);
  }
}

class Car {
  final int id;
  final String make;

  Car(this.id, this.make);

  static List<Car> getCars() {
    return <Car>[
      Car(1, "Ford"),
      Car(2, "Toyota"),
      Car(3, "BMW"),
    ];
  }
}

hallall je i madh