只是一个吸顶效果，拉下来的时候延时复位

listScroll(e) { 

let _this = this;

let index;

let fixedHeight = this.data.head_height

let fixedTop = this.data.fixedTop

if (e.detail.scrollTop > fixedTop && !this.data.bfixed) {

this.setData({

bfixed: true

});

} else if (e.detail.scrollTop < fixedTop && this.data.bfixed) {

this.setData({

bfixed: false,

});

}

//console.log(fixedHeight)

//测试方式1

for (let i in _this.data.sectionTopArray) {

if (e.detail.scrollTop > _this.data.sectionTopArray[i].top - fixedHeight) {

index = i

} else {

if (typeof index !== 'undefined') {

if (_this.data.navActiveId !== index) {

_this.setData({

navActiveId: index

});

}

break

}

}

}

},