Flutter直接选择组件插件reactive_direct_select的使用

Flutter 直接选择组件插件 reactive_direct_select 的使用

reactive_direct_select 是一个用于与 reactive_forms 配合使用的直接选择组件。它包装了 direct_select 组件，并提供了更方便的表单集成。

示例代码

以下是一个完整的示例，展示了如何在 Flutter 应用程序中使用 reactive_direct_select。

import 'package:flutter/material.dart';
import 'package:reactive_direct_select/reactive_direct_select.dart';
import 'package:reactive_forms/reactive_forms.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // 构建表单
  FormGroup buildForm() => fb.group({
        'input': FormControl<String>(value: 'Tunisia'),
      });

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: Scaffold(
        appBar: AppBar(),
        body: SafeArea(
          child: SingleChildScrollView(
            physics: const BouncingScrollPhysics(),
            padding: const EdgeInsets.symmetric(
              horizontal: 20.0,
              vertical: 20.0,
            ),
            child: ReactiveFormBuilder(
              form: buildForm,
              builder: (context, form, child) {
                return Column(
                  children: [
                    // 使用 ReactiveDirectSelect 组件
                    ReactiveDirectSelect<String, String>(
                      formControlName: 'input',
                      decoration: const InputDecoration(
                        border: OutlineInputBorder(),
                        suffixIcon: Icon(Icons.arrow_drop_down),
                      ),
                      itemExtent: 35.0,
                      items: const [
                        'Tunisia',
                        'Brazil',
                      ],
                      itemBuilder: (context, item) =>
                          item == null ? const SizedBox.shrink() : Text(item),
                      selectedItemBuilder: (context, item) =>
                          item == null ? const SizedBox.shrink() : Text(item),
                    ),
                    ElevatedButton(
                      child: const Text('Sign Up'),
                      onPressed: () {
                        if (form.valid) {
                          // 打印表单值
                          print(form.value);
                        } else {
                          // 如果表单无效，则标记所有字段为已触碰
                          form.markAllAsTouched();
                        }
                      },
                    ),
                  ],
                );
              },
            ),
          ),
        ),
      ),
    );
  }
}

代码说明

1. 导入必要的包

   import 'package:flutter/material.dart';
   import 'package:reactive_direct_select/reactive_direct_select.dart';
   import 'package:reactive_forms/reactive_forms.dart';
   

2. 创建主应用类

   void main() {
     runApp(const MyApp());
   }
   
   class MyApp extends StatelessWidget {
     const MyApp({super.key});
   

3. 构建表单

     // 构建表单
     FormGroup buildForm() => fb.group({
           'input': FormControl<String>(value: 'Tunisia'),
         });
   

4. 创建 Material 应用程序

     @override
     Widget build(BuildContext context) {
       return MaterialApp(
         title: 'Flutter Demo',
         theme: ThemeData(
           primarySwatch: Colors.blue,
           visualDensity: VisualDensity.adaptivePlatformDensity,
         ),
         home: Scaffold(
           appBar: AppBar(),
           body: SafeArea(
             child: SingleChildScrollView(
               physics: const BouncingScrollPhysics(),
               padding: const EdgeInsets.symmetric(
                 horizontal: 20.0,
                 vertical: 20.0,
               ),
               child: ReactiveFormBuilder(
                 form: buildForm,
                 builder: (context, form, child) {
                   return Column(
                     children: [
                       // 使用 ReactiveDirectSelect 组件
                       ReactiveDirectSelect<String, String>(
                         formControlName: 'input',
                         decoration: const InputDecoration(
                           border: OutlineInputBorder(),
                           suffixIcon: Icon(Icons.arrow_drop_down),
                         ),
                         itemExtent: 35.0,
                         items: const [
                           'Tunisia',
                           'Brazil',
                         ],
                         itemBuilder: (context, item) =>
                             item == null ? const SizedBox.shrink() : Text(item),
                         selectedItemBuilder: (context, item) =>
                             item == null ? const SizedBox.shrink() : Text(item),
                       ),
                       ElevatedButton(
                         child: const Text('Sign Up'),
                         onPressed: () {
                           if (form.valid) {
                             // 打印表单值
                             print(form.value);
                           } else {
                             // 如果表单无效，则标记所有字段为已触碰
                             form.markAllAsTouched();
                           }
                         },
                       ),
                     ],
                   );
                 },
               ),
             ),
           ),
         ),
       );
     }
   }