可以获取到接口对象，但是读不到具体内容是为什么啊

接口：
export interface userInfo{
  address:string
  age:number
  avatar:string
  flag:string
  id:number
  nickname:string
  password:string
  phone:string
  sex:string
  username:string
}
调用用户首选项：
async aboutToAppear(){
    this.vv = await preferencesUtil.getKey("myPreferences", 'userInfo', 'unknowns') as userInfo
    console.log('aboutToAppear==',this.vv)
    console.log('this.vv.avatar==',this.vv.avatar)
  }
log:
aboutToAppear== {"id":-1,"username":"未登录","password":"","age":-1,"sex":"-","nickname":"-","address":"-","phone":"-","avatar":'aaa',"flag":"1"}
this.vv.avatar== undefind
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