如图布局图，在点击查询后，在查询的状态下，下拉刷新，没有退出查询状态，下拉刷新失效，在第二次下拉才生效。在查询状态下，切换到其他页面，再回到该页面，没有回到初始页面，一直保持在查询状态下。

想要的效果是，在查询状态下，下拉刷新退出查询状态，回到初始页面状态，从其他页面切换到该页面，回到初始页面。

代码：

/**
   * 获取选项卡
   */
  onItemChengdeEvent(event) {
    var index = event.detail.index;
    // console.log(index);
    this.setData({
      currentIndex: index
    });
    if (!this.data.isQuerying) {
      this.lowdrelease();
    } else {
      this.onchaxun()
    }
  },
/**
   * 获取数据库数据
   */


  async loadData(start = 0, vehicle,newQuery = {}) {
    const that = this;
    const index = that.data.currentIndex;
    console.log(index);
    let query = {};
    switch (index) {
      case 0:
        break;
      case 1:
        query = {carpool: '我要找车'};
        break;
      case 2:
        query = {carpool: '我要找人'};
        break;
      case 3:
        query = {carpool: '我找货车'};
        break;
      case 4:
        query = {carpool: '我要找货'};
        break;
    }
    console.log(query)
    if (that.data.isQuerying) {
      newQuery = _.and(query,{
        startPoint: db.RegExp({
          regexp: '^' + that.data.startPoint
        }),
        goal: db.RegExp({
          regexp: '^' + that.data.goal
        }),
      })
    } else {
      newQuery = query
    }
    console.log('条件查询', newQuery)
    try {
      let promise = db.collection(vehicle).where(newQuery);
      if (start > 0) {
        promise = promise.skip(start);
      }
      promise = promise.limit(2)
        .orderBy("redden.reddenStartTime", 'desc')
        .orderBy("topping.toppingStarttime", "desc")
        .orderBy("create_time", "desc");
      const vehiclesRes = await promise.get();
      const vehicles = vehiclesRes.data;
      console.log('获取数据库数据', vehicles)
      const countResult = await promise.count();
      const total = countResult.total;
      console.log('总计数', total)
      const newVehicles = start > 0 ? this.data.vehicles.concat(vehicles) : vehicles;
      newVehicles.forEach((vehicle, index) => {
        vehicle.create_time = vehicle.create_time.toString();
      });
      const hasmore = false;
      return {
        newVehicles,
        total,
        hasmore,
      };
    } catch (error) {
      console.log('failed to load data:', error);
      throw error;
    }
  },
  /**
   * 获取初始数据
   */
  async lowdrelease(start = 0) {
    const that = this;
    try {
      const {
        newVehicles: vehicles,
        total: vehiclesTotal,
        hasmore: hasmore
      } = await that.loadData(start, 'vehicle');
      that.setData({
        vehicles: vehicles,
        hasmore: hasmore,
        result: vehiclesTotal,
      })
    } catch (error) {
      console.log('failed to load data:', error);
      throw error;
    }
  },
/**
   * 点击查询事件
   */
  async onchaxun(start = 0) {
    const that = this;
    that.setData({
      isQuerying:true
    })
    try {
      const {
        newVehicles: vehicles,
        total: vehiclesTotal,
        hasmore: hasmore
      } = await that.loadData(start, 'vehicle');


      that.setData({
        startPointStr: '',
        goalStr: '',
        vehicles: vehicles,
        hasmore: hasmore,
        result: vehiclesTotal,
      });
    } catch (error) {
      console.log('failed to load data:', error);
      throw error;
    }
  },
/**
   * 生命周期函数--监听页面显示
   */
  onShow() {
    this.lowdrelease(0);
  },
/**
   * 页面相关事件处理函数--监听用户下拉动作
   */
  onPullDownRefresh() {
    this.lowdrelease(0);
    this.setData({
      isQuerying: false
    })
    wx.stopPullDownRefresh();


  },