微信小程序wxs实现吸顶效果

<!-- wxml文件 -->
<wxs module="scroll1" src="./scroll1.wxs"></wxs> <!-- 引入wxs文件 -->
<scroll-view bindscroll="{{scroll1.scrollEvent}}" data-top="{{navTop}}" style='height:100%;' scroll-y>
 <image src='/images/top_image.png' mode='aspectFill' class='nav-image'></image>
 <view class='navigation'>
  <view wx:for="{{navBarList}}" wx:key="">{{item}}</view>
 </view>
 <view class='div' wx:for="{{8}}" wx:key="">第{{index}}部分</view>
</scroll-view>

/* wxss文件 */
page{
 font-size: 30rpx;
 background: #fea;
 height: 100%;
}
.div{
 width: 100%;height: 500rpx;
}
.nav-image{
 width: 100%;height: 400rpx;
 vertical-align: middle;
}
.navigation{
 width: 100%;
 height: 100rpx;
 display: flex;
 justify-content: center;
 align-items: center;
 background: #fff;
 top:0;left:0; /*只有使用定位才起效果*/
}
.navigation view{
 padding: 15rpx 20rpx;
 margin: 0 20rpx;
}

//wxs文件
var scrollEvent = function (e, ins) {
 var scrollTop = e.detail.scrollTop;
 var navTop = e.currentTarget.dataset.top;
 if (scrollTop >= navTop) {
  ins.selectComponent('.navigation').setStyle({
   "position": 'fixed'
  })
 } else {
  ins.selectComponent('.navigation').setStyle({
   "position": 'static'
  })
 }
}
module.exports = {
 scrollEvent: scrollEvent
}

//js文件
Page({
 /**
  * 页面的初始数据
  */
 data: {
  navBarList: ['喜欢', '点赞', '收藏'],
  navTop:0, //导航距顶部距离
 },
 /**
  * 生命周期函数--监听页面加载
  */
 onLoad: function (options) {
  this.getNavTop();
 },
 /**
  * 获取导航距顶部距离
  */
 getNavTop() {
  var that = this;
  var query = wx.createSelectorQuery();
  query.select('.navigation').boundingClientRect(function (data) {
   that.setData({
    navTop: data.top,
   })
  }).exec();
 },
 })

<!-- wxml文件 -->
<wxs module="scroll2" src="./scroll2.wxs"></wxs>
<scroll-view bindscroll="{{scroll2.scrollEvent}}" style='height:100%;' scroll-y>
 <!-- 头部 -->
 <image src='/images/top_image.png' mode='aspectFill' class='nav-image'></image>
 <view class='nav-icon'>
  <navigator open-type='navigateBack' class='back-icon'></navigator>
 </view>
 <view class='nav-bar' style='opacity:0;'>
  <navigator open-type='navigateBack' class='back-icon'></navigator>
  <view>我是导航条</view>
 </view>
 <!-- 头部 END -->
 <view class='div' wx:for="{{8}}" wx:key="">第{{index}}部分</view>
</scroll-view>

/* wxss文件 */
page{font-size: 30rpx;background: rgba(200, 58, 57, 0.3);height: 100%;}
.div{width: 100%;height: 500rpx;}
.nav-image{width: 100%;height: 400rpx;vertical-align: middle;}
.nav-icon,.nav-bar{
 position: fixed;
 top: 0;left: 0;
 height: 120rpx;
}
.nav-bar{
 width: 100%;
 display: flex;
 align-items: center;
 background: #fff;
}
.back-icon{
 width: 100rpx;
 height: 100%;
 display: flex;
 justify-content: center;
 align-items: center;
}
.back-icon::after{ /*利用伪类元素模拟出返回icon*/
 content: "";
 display: block;
 width: 25rpx;height: 25rpx;
 border-top: 5rpx solid #fff;
 border-left: 5rpx solid #fff;
 transform: rotate(-45deg);
}
.nav-bar .back-icon::after{border-color: #000;}

//wxs文件
var scrollEvent=function(e,ins){
 var scrollTop=e.detail.scrollTop;
 if(scrollTop>100){
  ins.selectComponent(".nav-icon").setStyle({
   "opacity":"0"
  })
  var dot = (scrollTop-100)/50;
  ins.selectComponent(".nav-bar").setStyle({
   "opacity": dot
  })
 }else{
  ins.selectComponent(".nav-bar").setStyle({
   "opacity": "0"
  })
  var dot = (100-scrollTop) / 50;
  ins.selectComponent(".nav-icon").setStyle({
   "opacity": dot
  })
 }
};
module.exports={
 scrollEvent: scrollEvent
};