DropdownButton class - material library - Dart API
API docs for the DropdownButton class from the material library, for the Dart programming language.
lib/my_first_page.dart
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
class MyFirstPage extends StatefulWidget {
const MyFirstPage({Key? key}) : super(key: key);
@override
State<MyFirstPage> createState() => _MyFirstPageState();
}
class _MyFirstPageState extends State<MyFirstPage> {
late TextEditingController _controller;
bool isChecked = false;
@override
void initState() {
super.initState();
_controller = TextEditingController();
}
@override
void dispose() {
_controller.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
Color getColor(Set<MaterialState> states) {
const Set<MaterialState> interactiveStates = <MaterialState>{
MaterialState.pressed,
MaterialState.hovered,
MaterialState.focused,
};
if (states.any(interactiveStates.contains)) {
return Colors.blue;
}
return Colors.red;
}
String dropdownValue = 'One';
return Scaffold(
appBar: AppBar(
title: Text(AppLocalizations.of(context)!.firstPage),
),
body: Container(
padding: const EdgeInsets.all(8),
child: Column(
children: <Widget>[
Text(AppLocalizations.of(context)!.firstPage),
TextField(
controller: _controller,
onSubmitted: (String value) async {
await showDialog<void>(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text('Title'),
content: Text(
'"$value", which has length ${value.characters.length}.'),
actions: <Widget>[
TextButton(
onPressed: () {
Navigator.pop(context);
},
child: const Text('OK'),
),
],
);
},
);
},
),
Checkbox(
checkColor: Colors.white,
fillColor: MaterialStateProperty.resolveWith(getColor),
value: isChecked,
onChanged: (bool? value) {
setState(() {
isChecked = value!;
});
}),
DropdownButton<String>(
value: dropdownValue,
icon: const Icon(Icons.arrow_downward),
iconSize: 24,
elevation: 16,
style: const TextStyle(color: Colors.deepPurple),
underline: Container(
height: 2,
color: Colors.deepPurpleAccent,
),
onChanged: (String? newValue) {
setState(() {
dropdownValue = newValue!;
});
},
items: <String>['One', 'Two', 'Free', 'Four']
.map<DropdownMenuItem<String>>((String value) {
return DropdownMenuItem<String>(
value: value,
child: Text(value),
);
}).toList(),
),
],
),
),
);
}
}
