Flutter对象扩展功能插件dart_object_extension的使用

该插件是一个用于Dart对象扩展的插件。

功能

• CopyWith（支持可空参数）

配置

在pubspec.yaml文件中添加以下依赖：

dependencies:
  ...
  dart_object_extension: latest

dev_dependencies:
  ...
  build_runner: ^2.1.11
  dart_object_extension_gen: latest

运行代码生成命令：

flutter pub run build_runner build

注解示例

CopyWith

例如，在student.dart文件中创建一个Person类：

import 'package:dart_object_extension/dart_object_extension.dart';

part 'person.g.dart';

@CopyWith()
class Person {
  final int id;
  final String name;
  final int? age;

  const Person({
    required this.id,
    required this.name,
    this.age,
  });
}

基本示例

const person = Person(id: 0, name: 'Jin');
final personOther = person.copyWith(
  name: () => 'Sugar',  // 更新名称为'Sugar'
  age: () => 25,        // 设置年龄为25
);

编译错误示例（名称不可为空）

const person = Person(id: 0, name: 'Jin');
final personOther = person.copyWith(
  name: () => null, // 这将导致编译错误，因为name不可为空
);

编译通过示例（年龄可以为空）

const person = Person(id: 0, name: 'Jin');
final personOther = person.copyWith(
  age: () => null, // 这将通过编译，因为age可以为空
);

完整示例Demo

以下是完整的示例代码，展示了如何在Flutter应用中使用dart_object_extension插件。

import 'package:flutter/material.dart';

import 'models/person.dart'; // 导入Person模型

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  [@override](/user/override)
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Person _person = const Person(id: 0, name: 'Jin'); // 初始化Person对象

  [@override](/user/override)
  void initState() {
    super.initState();
  }

  void _incrementCounter() {
    setState(() {
      _person = _person.copyWith(
        name: () => 'Sugar',  // 更新名称为'Sugar'
        age: () => 25,        // 设置年龄为25
      );
    });
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Text('Person Name'), // 显示Person的名称
            Text(
              _person.name,
              style: Theme.of(context).textTheme.bodyLarge,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter, // 按钮点击事件
        tooltip: 'Change',
        child: const Icon(Icons.cached), // 图标
      ),
    );
  }
}