为什么使用preferences的flush持久化成功的数据在重启应用后还是被清除了

import { preferences } from '@kit.ArkData';
import common from '@ohos.app.ability.common';

class Store {
  private dataPreferences: preferences.Preferences | null = null;
  private context: common.UIAbilityContext | null = null;

  /** 初始化 */
  init(context: common.UIAbilityContext) {
    this.context = context
    preferences.getPreferences(context, 'myStore', (err: BusinessError, obj: preferences.Preferences) => {
      if (err === undefined) {
        console.log('初始化成功')
        this.dataPreferences = obj
      } else {
        this.dataPreferences = null
        console.log('失败原因:', err.message)
      }
    });
  }

  /** 设置token */
  setToken(token: string) {
    console.log('设置token', token);
    this.dataPreferences?.put('token', token, (err: BusinessError) => {
      if (err === undefined) {
        console.log('写入成功')
        this.flushToken()
      } else {
        this.setToken(token)
      }
    })

  }

  /** 持久化token */
  flushToken() {
    this.dataPreferences?.flush((flushErr: BusinessError) => {
      if (flushErr === undefined) {
        console.log('持久化成功')
      } else {
        console.log('持久化失败:', flushErr.message)
        this.flushToken()
      }
    })
  }

  /** 获取token */
  getToken(): string {
    try {
      return this.dataPreferences?.getSync('token', '') as string
    } catch (err) {
      return ''
    }

  }

  /** 清除token */
  removeToken() {
    this.dataPreferences?.delete('token', (err: BusinessError) => {
      if (err === undefined) {
        console.log('删除成功')
        this.flushToken()
      } else {
        this.removeToken()
      }
    })
  }
}

export default new Store()
在EntryAbility中初始化,在其它页面使用set和get方法均成功,但是重启应用后数据就没有了,使用的是模拟器(Mate 80 Pro Max)