绿色添加按钮用绝对定位，为什么会随滚动条加载更多页面而变化位置？后面再加载更多数据也不会变化位置了，这个高度我是用屏幕高度来设置的，为啥还会变化？

<template name=“addButton”>

<navigator class=“addButton” style=“position:absolute;z-index: 999;  top:{{addButtonTop}};  left:80%;opacity:1;  background-color:#34b60d;  color:rgb(255,255,255);height:107.5rpx;  width:107.5rpx;  border-radius: 50%;transform: translate(0, -50%);  line-height: 107.5rpx;  font-size:60.46875rpx;  text-align: center;” url="{{router}}" hover-class=“navigator-hover”>+</navigator>

</template>

<template is=“addButton” data="{{router:’/pages/pageAddKaiguan/pageAddKaiguan?currentshebei=’+currentShebei,addButtonTop:addButtonTop}}"></template>

.addButton{

position:absolute;

z-index: 999;

top:90%;

left:80%;

opacity:1;

background-color:#34b60d;

color:rgb(255,255,255);

height:107.5rpx;

width:107.5rpx;

border-radius: 50%;

transform: translate(0, -50%);

line-height: 107.5rpx;

font-size:60.46875rpx;

text-align: center;

}

onLaunch: function () {

wx.getSystemInfo({

success: function(res) {

var kScreenW=res.windowWidth/375;

var kScreenH=res.windowHeight/603;

wx.setStorageSync(‘kScreenW’, kScreenW);

wx.setStorageSync(‘kScreenH’, kScreenH);

},

})

}

pageScrollFunc: function (compid, curpage) {

currentPage.setData({

“addButtonTop”: wx.getStorageSync(‘kScreenH’)*604 - 45 + “px”

});

}

在onLaunch里获取屏幕高度保存本地，滚动条绑定向下滚动事件到pageScrollFunc，为什么位置还是没有固定住？？？