Desliza hacia arriba y hacia abajo para mostrar el código QR

<view class="pages">
	<view class="pagesTop">
		<image mode='widthFix' src="https://sucai.suoluomei.cn/sucai_zs/images/20200831095626-1598838867%281%29.png">
		</image>
	</view>
	<view bindtouchstart="touchMove" class="pagesButon" style="position: absolute;top:{
       
       {
       
       height}}rpx" bindtap="xioama">
			哈哈哈
	</view>
</view>

var app = getApp();
Page({
    
    
  data: {
    
    
    height:'302'
  },
  /**
   * 生命周期函数--监听页面加载
   */
  onLoad: function(options) {
    
    
    setTimeout(() =>{
    
    
      this.setData({
    
    
        height:'741'
      })
    },500)
  },
  touchMove(e){
    
    
    if(this.data.height == '302'){
    
    
      this.setData({
    
    
        height:'741'
      })
    }else{
    
    
      this.setData({
    
    
        height:'302'
      })
    }
  },
})

.pages {
    
    
  position: relative;
  width: 100%;
}

.pagesTop {
    
    
  width: 100%;
  z-index: 1;
}

.pagesTop image {
    
    
  width: 100%;
}

.pagesButon {
    
    
  transition-duration: 1s;
  width: 100%;
  background: #fff;
  color: #000;
  height: 600rpx;
  z-index: 99;
  border-top-right-radius: 30rpx;
  border-top-left-radius: 30rpx;
}