Flutter不连续范围选择插件discontinuous_range的使用

Flutter 不连续范围选择插件 discontinuous_range 的使用

discontinuous_range 是一个用于处理不连续数字范围的 Dart 插件。它可以用来添加或减去一系列数字范围。

示例代码

以下是一个完整的示例代码，展示了如何在 Flutter 中使用 discontinuous_range 插件来处理不连续范围的选择。

import 'dart:math';
import 'package:flutter/material.dart';
import 'package:discontinuous_range/discontinuous_range.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('不连续范围选择插件示例')),
        body: RangeExample(),
      ),
    );
  }
}

class RangeExample extends StatefulWidget {
  @override
  _RangeExampleState createState() => _RangeExampleState();
}

class _RangeExampleState extends State<RangeExample> {
  late DRange allNums;
  late DRange badNums;
  late DRange goodNums;

  @override
  void initState() {
    super.initState();
    allNums = DRange(1, 100); // [ 1-100 ]
    badNums = DRange(13)
      ..add(DRange(8))
      ..add(DRange(60, 80)); // [8, 13, 60-80]
    goodNums = allNums.clone()..subtract(badNums);
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Text(
            '有效的数字范围：${goodNums.toString()}',
            style: TextStyle(fontSize: 18),
          ),
          SizedBox(height: 20),
          ElevatedButton(
            onPressed: () {
              int randomGoodNum =
                  goodNums.index((Random().nextDouble() * goodNums.length).floor());
              setState(() {
                // 更新随机数
              });
              showDialog(
                context: context,
                builder: (BuildContext context) {
                  return AlertDialog(
                    title: Text('随机选择的数字'),
                    content: Text('$randomGoodNum'),
                    actions: <Widget>[
                      TextButton(
                        child: Text('确定'),
                        onPressed: () {
                          Navigator.of(context).pop();
                        },
                      ),
                    ],
                  );
                },
              );
            },
            child: Text('随机选择一个有效数字'),
          ),
        ],
      ),
    );
  }
}

代码解释

1. 导入必要的库：

   import 'dart:math';
   import 'package:flutter/material.dart';
   import 'package:discontinuous_range/discontinuous_range.dart';
   

2. 定义主应用类：

   void main() {
     runApp(MyApp());
   }
   
   class MyApp extends StatelessWidget {
     @override
     Widget build(BuildContext context) {
       return MaterialApp(
         home: Scaffold(
           appBar: AppBar(title: Text('不连续范围选择插件示例')),
           body: RangeExample(),
         ),
       );
     }
   }
   

3. 定义范围选择示例类：

   class RangeExample extends StatefulWidget {
     @override
     _RangeExampleState createState() => _RangeExampleState();
   }
   
   class _RangeExampleState extends State<RangeExample> {
     late DRange allNums;
     late DRange badNums;
     late DRange goodNums;
   
     @override
     void initState() {
       super.initState();
       allNums = DRange(1, 100); // [ 1-100 ]
       badNums = DRange(13)
         ..add(DRange(8))
         ..add(DRange(60, 80)); // [8, 13, 60-80]
       goodNums = allNums.clone()..subtract(badNums);
     }
   
     @override
     Widget build(BuildContext context) {
       return Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
             Text(
               '有效的数字范围：${goodNums.toString()}',
               style: TextStyle(fontSize: 18),
             ),
             SizedBox(height: 20),
             ElevatedButton(
               onPressed: () {
                 int randomGoodNum =
                     goodNums.index((Random().nextDouble() * goodNums.length).floor());
                 setState(() {
                   // 更新随机数
                 });
                 showDialog(
                   context: context,
                   builder: (BuildContext context) {
                     return AlertDialog(
                       title: Text('随机选择的数字'),
                       content: Text('$randomGoodNum'),
                       actions: <Widget>[
                         TextButton(
                           child: Text('确定'),
                           onPressed: () {
                             Navigator.of(context).pop();
                           },
                         ),
                       ],
                     );
                   },
                 );
               },
               child: Text('随机选择一个有效数字'),
             ),
           ],
         ),
       );
     }
   }