Flutter代码质量检查插件lint的使用

简介

lint 是一个为Dart和Flutter项目提供的开源社区驱动的代码质量检查工具。它遵循 Effective Dart: Style Guide 的规则，旨在帮助开发者编写更清晰、更一致的代码。

lint 支持三种不同严格程度的规则集：

• strict：适用于生产环境的应用代码，规则较为严格但不会过于繁琐。
• casual：适用于原型开发、代码示例或其他非生产环境的代码，规则较为宽松。
• package：适用于具有公共API的Dart包，类似于 strict 规则集。

安装

1. 添加依赖

在项目的 pubspec.yaml 文件中添加 lint 作为开发依赖：

dev_dependencies:
  lint: ^2.0.0

2. 创建 analysis_options.yaml

在项目的根目录下创建 analysis_options.yaml 文件，并根据需要选择合适的规则集：

include: package:lint/strict.yaml # For production apps
# include: package:lint/casual.yaml # For code samples, hackathons and other non-production code
# include: package:lint/package.yaml # Use this for packages with public API

analyzer:
  exclude:
    #- '**.freezed.dart'
    #- '**.g.dart'

linter:
  rules:
    # Customize the rules as per your project's needs
    sort_constructors_first: true
    prefer_single_quotes: true
    public_member_api_docs: true
    always_specify_types: true
    lines_longer_than_80_chars: true
    always_put_required_named_parameters_first: false
    avoid_classes_with_only_static_members: false

使用示例

以下是一个完整的示例项目结构，展示了如何配置 lint 并应用规则：

项目结构

my_flutter_app/
├── lib/
│   └── main.dart
├── pubspec.yaml
└── analysis_options.yaml

pubspec.yaml

name: my_flutter_app
description: A new Flutter application.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

environment:
  sdk: ">=2.12.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

dev_dependencies:
  flutter_test:
    sdk: flutter
  lint: ^2.0.0

flutter:
  uses-material-design: true

analysis_options.yaml

include: package:lint/strict.yaml

analyzer:
  exclude:
    - '**.freezed.dart'
    - '**.g.dart'

linter:
  rules:
    sort_constructors_first: true
    prefer_single_quotes: true
    public_member_api_docs: true
    always_specify_types: true
    lines_longer_than_80_chars: true
    always_put_required_named_parameters_first: false
    avoid_classes_with_only_static_members: false

lib/main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  final String title;

  MyHomePage({required this.title});

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

Lint Badge

如果你在开源项目中使用了 lint，可以在 README.md 中添加一个徽章来展示你遵循严格的 lint 规则：

## 版本选择

根据你的 Dart 版本选择合适的 `lint` 版本。通常情况下，你可以直接使用 `^2.0.0` 来获取与 Dart 版本兼容的最新版本。

| Dart Version | Lint Version |
|--------------|--------------|
| 3.1          | [2.2.0](https://pub.dev/packages/lint/versions/2.2.0/changelog) |
| 3.0          | [2.1.0](https://pub.dev/packages/lint/versions/2.1.0/changelog) |
| 2.18         | [2.0.0](https://pub.dev/packages/lint/versions/2.0.0/changelog) |
| 2.17         | [1.10.0](https://pub.dev/packages/lint/versions/1.10.0/changelog) |
| 2.16         | [1.9.0](https://pub.dev/packages/lint/versions/1.9.0/changelog) |
| 2.15         | [1.8.0](https://pub.dev/packages/lint/versions/1.8.0/changelog) |
| 2.14         | [1.7.0](https://pub.dev/packages/lint/versions/1.7.0/changelog) |
| 2.13         | [1.6.0](https://pub.dev/packages/lint/versions/1.6.0/changelog) |
| 2.12         | [1.5.0](https://pub.dev/packages/lint/versions/1.5.0/changelog) |

## 总结

通过配置 `lint` 插件，你可以确保你的 Flutter 项目遵循最佳实践和一致的编码风格。合理选择规则集并根据项目需求进行定制化配置，将有助于提高代码质量和可维护性。希望这个指南对你有所帮助！如果有任何问题或需要进一步的帮助，请随时提问。