首先在 pubspec.yaml 文件中添加 shared_preferences 引用并 Packages get
dependencies:
  flutter:
    sdk: flutter
 
  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  shared_preferences: 
然后封装 SharedPreferences 工具类
import 'package:shared_preferences/shared_preferences.dart';
 
/**
 * @des SharedPreferences 工具类
 * @author liyongli 20190522
 * */
class SharedPreferencesDataUtils{
 
  // 保存数据
  Future setUserInfo(key, value) async{
    SharedPreferences sp = await SharedPreferences.getInstance();
    sp.setString(key, value);
  }
 
  // 获取数据
  Future getUserInfo(key) async{
    SharedPreferences sp = await SharedPreferences.getInstance();
    print(sp.get(key));
    return sp.get(key);
  }
 
  // 清除数据
  Future deleteUserInfo(key) async{
    SharedPreferences sp = await SharedPreferences.getInstance();
    sp.remove(key);
  }
 
}
调用方式
    SharedPreferencesDataUtils spDataUtils = new SharedPreferencesDataUtils();
 
    spDataUtils.setUserInfo("name","Flutter Flutter Flutter");
    spDataUtils.setUserInfo("type","Save Save Save");
 
    print(dataUtils.getUserInfo("name"));
    print(dataUtils.getUserInfo("type"));
运行结果
    I/flutter (13801): Flutter Flutter Flutter
    I/flutter (13801): Save Save Save