import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
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> {
int _counter = 0;
List<int> myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
int currentNumber = 1;
int anotherNumber = 9;
void _incrementCounter() {
setState(() {
_counter++;
anotherNumber = _counter;
currentNumber = _counter;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
DropdownButtonFormField<int>(
value: currentNumber,
items: myList.map((int value) {
return DropdownMenuItem<int>(
value: value,
child: Container(
width: 200,
child: Text(
value.toString(),
),
),
);
}).toList(),
onChanged: (int newValue) {
setState(() {
anotherNumber = newValue;
currentNumber = newValue;
});
},
),
DropdownButtonFormField<int>(
value: anotherNumber,
items: myList.map((int value) {
return DropdownMenuItem<int>(
value: value,
child: Container(
width: 200,
child: Text(
value.toString(),
),
),
);
}).toList(),
onChanged: (int newValue) {
setState(() {
anotherNumber = newValue;
});
},
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
$ flutter doctor -v
[✓] Flutter (Channel stable, v1.17.0, on Mac OS X 10.15.4 19E287, locale en-RS)
• Flutter version 1.17.0 at /Users/lazarjovicic/flutter
• Framework revision e6b34c2b5c (9 days ago), 2020-05-02 11:39:18 -0700
• Engine revision 540786dd51
• Dart version 2.8.1
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
• Android SDK at /Users/lazarjovicic/Library/Android/sdk
• Platform android-29, build-tools 29.0.2
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 11.4.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 11.4.1, Build version 11E503a
• CocoaPods version 1.8.4
[✓] Android Studio (version 3.6)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 45.1.1
• Dart plugin version 192.7761
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)
[✓] VS Code (version 1.44.2)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.10.1
[✓] Connected device (1 available)
• SM G970F • RF8M728WTMP • android-arm64 • Android 10 (API 29)
• No issues found!
Please let me know if you need additional information or any further explanation regarding the problem.
I just created a simple app in order to see what am I doing wrong
The code:
The flutter doctor -v:
The demonstration with code above:
https://streamable.com/fwwd46
EDIT:
The Expectation:
Update the first dropdown filed -> the second dropdown field will be updated automatically
The Result:
Update the first dropdown field -> the second dropdown field remains unchanged.
Please let me know if you need additional information or any further explanation regarding the problem.
Thanks