HarmonyOS dataPreferences如何持久化存储数据，重启app后被清空？

Question

代码实现：

export class UserCache {
  //首选项
  private preferences: dataPreferences.Preferences | null = null;

  private constructor() {
  }

  private static instance: UserCache

  public static getInstance(): UserCache {
    if (!UserCache.instance) {
      UserCache.instance = new UserCache();
    }
    return UserCache.instance;
  }


  initConfig(context: Context) {
    dataPreferences.getPreferences(context, APP_STORE_PREFERENCES,
      (error: BusinessError, val: dataPreferences.Preferences) => {
        if (error) {
          return;
        }
        this.preferences = val
      })
  }

  saveLoginInfo(model: LoginModel) {
    this.saveTokenSync(model.token)
    this.saveUserNameSync(model.userName)
    this.saveUserIdSync(model.userId)
    this.saveUniqueCodeSync(model.uniqueCode)
  }

  /**
   * 同步保存token
   * @param tokenStr
   */
  saveTokenSync(tokenStr: string) {
    this.preferences?.putSync(USER_TOKEN, tokenStr)
  }

  /**
   * 同步保存token
   * @param tokenStr
   */
  saveUserIdSync(userId: string) {
    this.preferences?.putSync(USER_ID, userId)
  }

  /**
   * 同步保存userName
   * @param username
   */
  saveUserNameSync(username: string) {
    this.preferences?.putSync(USER_NAME, username)
  }

  /**
   * 同步保存uniqueCode
   * @param uniqueCode
   */
  saveUniqueCodeSync(uniqueCode: string) {
    this.preferences?.putSync(UNIQUE_CODE, uniqueCode)
  }


  /**
   * 同步获取token
   * @returns token
   */
  getTokenSync() {
    return (this.preferences?.getSync(USER_TOKEN, "") ?? "").toString()
  }

  /**
   * 同步获取userName
   * @returns
   */
  getUserNameSync() {
    return (this.preferences?.getSync(USER_NAME, "") ?? "").toString()
  }

  /**
   * 判断是否登录
   * @returns 是否登录
   */
  isLoginSync() {
    const token = (this.getTokenSync() ?? "").toString()
    console.log("isLoginSync", this.getTokenSync())
    console.log("isLoginSync", token)
    return token.length > 0
  }

  /**
   * 清除缓存信息
   */
  cleanCache() {
    this.saveUserNameSync("")
    this.saveTokenSync("")
    this.saveUserIdSync("")
    this.saveUniqueCodeSync("")
  }
}

Answer 1

需要持久化时可以使用flush接口将内存中的数据写入持久化文件中。参考链接：https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/data-persistence-by-preferences-V5

确认ide的相关设置：点击IDE页面菜单栏run-\>Edit　Confingurations。确定Keep Application Data是否勾选。