微信小程序swiper切换卡内嵌滚动条不显示

<view class="swiper-tab"> 
  <view class="swiper-tab-item {{currentTab==0 ? 'on' : ''}}" data-current="0" bindtap="swichNav">为你推荐</view> 
  <view class="swiper-tab-item {{currentTab==1 ? 'on' : ''}}" data-current="1" bindtap="swichNav">新品上架</view> 
  <view class="swiper-tab-item {{currentTab==2 ? 'on' : ''}}" data-current="2" bindtap="swichNav">最热商品</view> 
</view> 
<swiper current="{{currentTab}}" class="swiper-box" duration="300" style="height:{{clientHeight?clientHeight-'40'+'px':'auto'}}" bindchange="bindChange" > 

  <swiper-item> 
  <scroll-view scroll-y="{{true}}" style="height: {{clientHeight?clientHeight+'px':'auto'}}">
   <view style='height:200px'>为你推荐</view> 
   <view style='height:200px'>为你推荐</view> 
   <view style='height:200px'>为你推荐</view> 
   <view style='height:200px'>为你推荐</view> 
   <view style='height:200px'>为你推荐</view>
  </scroll-view>
  </swiper-item> 


  <swiper-item> 
   <view>新品上架</view> 
  </swiper-item> 


  <swiper-item> 
   <view>最热商品</view> 
  </swiper-item> 



</swiper> 

/**index.wxss**/
.userinfo {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.userinfo-avatar {
  width: 128rpx;
  height: 128rpx;
  margin: 20rpx;
  border-radius: 50%;
}

.userinfo-nickname {
  color: #aaa;
}

.usermotto {
  margin-top: 200px;
}


.swiper-tab {
  width: 100%;
  text-align: center;
  line-height: 80rpx;
  margin-top:10rpx;
  margin-bottom: 20rpx;
}

.swiper-tab-item {
  font-size: 30rpx;
  display: inline-block;
  width: 33.33%;
  color: #666;
}

.on {
  color: #FEA611;
  border-bottom: 5rpx solid #FEA611;
}

.swiper-box {
  display: block;
  height: 100%;
  width: 100%;
  overflow: hidden;
}

.swiper-box view {
  text-align: center;
}

//index.js
//获取应用实例
const app = getApp()

Page({
  data: {
    motto: 'Hello World',
    userInfo: {},
    hasUserInfo: false,
    canIUse: wx.canIUse('button.open-type.getUserInfo'),
    clientWidth: 0,
    clientHeight: 0,
    // tab切换 
    currentTab: 0
  },
  //事件处理函数
  bindViewTap: function () {
    wx.navigateTo({
      url: '../logs/logs'
    })
  },
  onLoad: function () {
    var that = this;
    wx.getSystemInfo({
      success: function (res) {
        that.setData({
          clientHeight: res.windowHeight
        });
      }
    });
    if (app.globalData.userInfo) {
      this.setData({
        userInfo: app.globalData.userInfo,
        hasUserInfo: true
      })
    } else if (this.data.canIUse) {
      // 由于 getUserInfo 是网络请求，可能会在 Page.onLoad 之后才返回
      // 所以此处加入 callback 以防止这种情况
      app.userInfoReadyCallback = res => {
        this.setData({
          userInfo: res.userInfo,
          hasUserInfo: true
        })
      }
    } else {
      // 在没有 open-type=getUserInfo 版本的兼容处理
      wx.getUserInfo({
        success: res => {
          app.globalData.userInfo = res.userInfo
          this.setData({
            userInfo: res.userInfo,
            hasUserInfo: true
          })
        }
      })
    }
  },
  getUserInfo: function (e) {
    console.log(e)
    app.globalData.userInfo = e.detail.userInfo
    this.setData({
      userInfo: e.detail.userInfo,
      hasUserInfo: true
    })
  },
  bindChange: function (e) {

    var that = this;
    that.setData({ currentTab: e.detail.current });

  },

  swichNav: function (e) {

    var that = this;

    if (this.data.currentTab === e.target.dataset.current) {
      return false;
    } else {
      that.setData({
        currentTab: e.target.dataset.current
      })
    }
  }  
})