微信小程序自制scroll-view横向滑动滚动条(仿拼多多)

效果图

实现代码 
index.wxml

<scroll-view scroll-x="true" class="scroll-view-x" style="padding-top:10rpx" scroll-with-animation="true" wx:if="{{tlist[currentTab].secondList}}" scroll-left='0' bindscroll="getleft">
<!--内容区域-->
<view>
<view class="navigator_second" wx:for="{{tlist[currentTab].secondList}}" wx:for-item="childItem" bindtap="getProductList" data-id="{{childItem.id}}">
<image class="navigator_icon" src="{{childItem.icon}}"></image>
<text class="navigator_text">{{childItem.name}}</text>
</view>
</view>
<view wx:if="{{tlist[currentTab].thirdList}}">
<view class="navigator_second" wx:for="{{tlist[currentTab].thirdList}}" wx:for-item="childItem" data-id="{{childItem.id}}" bindtap="getProductList">
<image class="navigator_icon" src="{{childItem.icon}}" ></image>
<text class="navigator_text">{{childItem.name}}</text>
</view>
</view>
</scroll-view >
<!--滚动条部分-->
<view wx:if="{{slideShow}}" class="slide">
<view class='slide-bar' >
<view class="slide-show" style="width:{{slideWidth}}rpx; margin-left:{{slideLeft<=1 ? 0 : slideLeft+'rpx'}};"></view>
</view>
</view>

index.js

//获取应用实例
var app = getApp();
Page({
  data: {
    navigate_type:'',//分类类型，是否包含二级分类
    slideWidth:'',//滑块宽
    slideLeft:0 ,//滑块位置
    totalLength:'',//当前滚动列表总长
    slideShow:false,
    slideRatio:''
  },
  onLoad: function () {
    var self = this ;
    var systemInfo = wx.getSystemInfoSync() ;
    self.setData({
      list: _list,
      windowHeight: app.globalData.navigate_type == 1 ? systemInfo.windowHeight : systemInfo.windowHeight - 35,
      windowWidth: systemInfo.windowWidth,
      navigate_type: app.globalData.navigate_type
    })
    //计算比例
    self.getRatio();
  },
  //根据分类获取比例
  getRatio(){
    var self = this ;
    if (!self.data.tlist[self.data.currentTab].secondList || self.data.tlist[self.data.currentTab].secondList.length<=5){
      this.setData({
        slideShow:false
      })
    }else{
      var _totalLength = self.data.tlist[self.data.currentTab].secondList.length * 150; //分类列表总长度
      var _ratio = 230 / _totalLength * (750 / this.data.windowWidth); //滚动列表长度与滑条长度比例
      var _showLength = 750 / _totalLength * 230; //当前显示红色滑条的长度(保留两位小数)
      this.setData({
        slideWidth: _showLength,
        totalLength: _totalLength,
        slideShow: true,
        slideRatio:_ratio
      })
    }
  } ,
  //slideLeft动态变化
  getleft(e){
    this.setData({
      slideLeft: e.detail.scrollLeft * this.data.slideRatio
    })
  } 
})

index.wxss

.scroll-view-x{
   background-color: #fff;
   white-space: nowrap;
}
.navigator_second{
  width:150rpx;
  text-align:center;
  display:inline-block;
  height:115rpx;
}
.navigator_icon{
  width:60rpx;
  height:60rpx;
}
.navigator_text{
  display:block;
  width:100%;
  font-size:24rpx
}
.slide{
  height:30rpx;
  background:#fff;
  with:100%;
  padding:14rpx 0 5rpx 0
}
.slide .slide-bar{
  width:230rpx;
  margin:0 auto;
  height:1.5px;
  background:#eee;
}
.slide .slide-bar .slide-show{
  height:100%;
  background-color:#ff6969;

}