在一條線上滑動,得到不同的值。
/// Flutter code sample for Slider
// ![A slider widget, consisting of 5 divisions and showing the default value
// indicator.](https://flutter.github.io/assets-for-api-docs/assets/material/slider.png)
//
// The Sliders value is part of the Stateful widget subclass to change the value
// setState was called.
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
/// This is the main application widget.
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
static const String _title = 'Flutter Code Sample';
@override
Widget build(BuildContext context) {
return MaterialApp(
title: _title,
home: Scaffold(
appBar: AppBar(title: const Text(_title)),
body: const MyStatefulWidget(),
),
);
}
}
/// This is the stateful widget that the main application instantiates.
class MyStatefulWidget extends StatefulWidget {
const MyStatefulWidget({Key? key}) : super(key: key);
@override
State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}
/// This is the private State class that goes with MyStatefulWidget.
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
double _currentSliderValue = 20;
@override
Widget build(BuildContext context) {
return Slider(
value: _currentSliderValue,
min: 0,
max: 100,
divisions: 5,
label: _currentSliderValue.round().toString(),
onChanged: (double value) {
setState(() {
_currentSliderValue = value;
});
},
);
}
}