let query = wx.createSelectorQuery().in(this)
let _this = this
console.log(query.select)
query.select('#move-box').boundingClientRect(function (rect) {
console.log(rect)
_this.maxWidth = rect.width
console.log(_this.maxWidth)
}).exec(res => {
console.log(res)
})

ready生命周期中，在子组件获取元素高度， 控制台

An SelectorQuery call is ignored because no proper page or component is found. Please considering using SelectorQuery.in to specify a proper one.

如果不使用in(this), 获取的rect是null