Slide 的用法

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;
        });
      },
    );
  }
}