微信小程序实现原生步骤条

<view class='window'>
 <view class='content' bindtouchstart='touchS' bindtouchend='touchE' style='left:{{left}}rpx'>
  <view wx:for="{{list}}">
   <!-- 时间线 -->
   <view class='pot'>
    <view class='{{index == 0?"blank":"line"}}'></view>   
    <view class='circle' style='background:{{show_index == index?"orange":""}}'></view>
    <view class='{{index == length - 1?"blank":"line"}}'></view>
   </view>
   <!-- 图片 -->
   <view class='pic_container'>
    <image class='pic' style='{{show_index != index?"transform:scale(0.5,0.5)":""}}' src="../../images/{{index+1}}.jpg"></image>
   </view>
  </view>
 </view>
</view>

.window{
 width: 450rpx;
 background-color: #eee;
 padding: 25rpx;
 position: relative;
 overflow: hidden;
 margin: 0 auto;
 border-radius: 20rpx;
}
.content{
 display: flex;
 position: relative;
 transition: all 0.5s;
}
.content>view{
 display: flex;
 flex-direction: column;
 align-items: center;
}
.pot{
 width: 450rpx;
 display: flex;
 align-items: center;
 justify-content: space-between;
}
.circle{
 border-radius: 100%;
 height: 20rpx;
 width: 20rpx;
 border:4rpx solid orange;
}
.line{
 height: 4rpx;
 width: 50%;
 background: orange;
}
.blank{
 height: 4rpx;
 width: 50%;
}
.pic_container{
 width: 450rpx;
 height: 450rpx;
 display: flex;
 justify-content:center;
 align-items: center;
}
.pic{
 width: 400rpx;
 height: 400rpx;
 transition: all 0.5s;
}

Page({
 data: {
  list: ['1', '2', '3'],
  left:0,
  show_index:0
 },
 
 onLoad: function () {
  this.setData({
   length:this.data.list.length
  })
 },
 
 touchS:function(e){
  var that = this;
  this.data.start = e.touches[0].pageX;
  this.data.start_left = this.data.left;
 },
 
 touchE:function(e){
  var that = this;
  this.data.end = e.changedTouches[0].pageX;
  var distance = this.data.end - this.data.start;
  //左滑
  if (distance <= -40 && this.data.left > -900) {
   this.setData({
    left: that.data.start_left - 450,
    show_index:++ this.data.show_index
   })
  }
  //不滑
  else if(distance <= 40){
   this.setData({
    left: that.data.start_left,
   })
  }
  //右滑
  else if (distance > 40 && this.data.left < 0) {
   this.setData({
    left: that.data.start_left + 450,
    show_index: --this.data.show_index
   })
  }
 }
 
})