Flutter偏好设置管理插件sp_util的使用

sp_util

sp_util 是一个用于Flutter项目的共享偏好设置插件，它简化了SharedPreferences的使用，支持获取默认值、保存对象和对象列表。以下是其主要功能和使用方法。

Pub配置

在pubspec.yaml文件中添加依赖：

dependencies:
  sp_util: ^2.0.3

API接口

• getObj, getObjList, putObject, getObject, putObjectList, getObjectList
• getString, putString
• getBool, putBool
• getInt, putInt
• getDouble, putDouble
• getStringList, putStringList
• getDynamic
• haveKey
• getKeys
• remove
• clear
• reload
• isInitialized

示例代码

初始化与基本用法

确保在应用启动前完成SpUtil的初始化。这通常是在main()函数中进行异步等待。

import 'package:flutter/material.dart';
import 'package:sp_util/sp_util.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await SpUtil.getInstance();
  runApp(MyApp());
}

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

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

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  String spLastCounter = 'last_counter';

  void _incrementCounter() {
    setState(() {
      _counter++;
      SpUtil.putInt(spLastCounter, _counter);
    });
  }

  @override
  void initState() {
    super.initState();

    // 使用sp读取上次计数
    _counter = SpUtil.getInt(spLastCounter, defValue: 0)!;
  }

  @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),
      ),
    );
  }
}

对象存储示例

除了简单的数据类型外，sp_util还支持复杂的对象和对象列表的存储与读取。

class City {
  String name;

  City({required this.name});

  factory City.fromJson(Map<String, dynamic> json) => City(name: json['name']);
  
  Map<String, dynamic> toJson() => {'name': name};
}

// 存储单个对象
City city = City(name: "成都市");
SpUtil.putObject("loc_city", city);

// 读取单个对象
City? hisCity = SpUtil.getObj("loc_city", (v) => City.fromJson(v as Map<String, dynamic>));
print("City: " + (hisCity == null ? "null" : hisCity.toString()));

// 存储对象列表
List<City> list = [];
list.add(City(name: "成都市"));
list.add(City(name: "北京市"));
SpUtil.putObjectList("loc_city_list", list);

// 读取对象列表
List<City>? dataList = SpUtil.getObjList("loc_city_list", (v) => City.fromJson(v as Map<String, dynamic>));
print("CityList: " + (dataList == null ? "null" : dataList.toString()));

通过上述内容，您可以轻松地在Flutter项目中集成并使用sp_util来管理和持久化应用程序的数据。此外，如果您需要更多工具类的支持，可以考虑引入common_utils或flustars库。