import React, { Component } from 'react'
import { View, Text, ScrollView } from '@tarojs/components'
import { createSelectorQuery } from '@tarojs/taro'
import './index.scss'
const tabList = [{name: '头', value: 'header'},{name: '内容',value: 'content'},{name: '底部', value: 'footer'}]
export default class Index extends Component {
state ={
activeStatus: 'header',
heightArr: [],
activeIndex:0
}
handleTab(value, index) {
this.setState({
activeStatus: value,
activeIndex: index
})
}
handleScroll({detail}) {
let heightArr = []
let number = 0
// 获取节点距离容器顶部的高度
tabList.map(item => {
createSelectorQuery().select(`#${item.value}`).boundingClientRect(res => {
number = res.height + number
heightArr.push(number)
this.setState({
heightArr: heightArr
})
}).exec()
})
// 根据滚动定位节点
const scrollTop = Math.ceil(detail.scrollTop)
const { heightArr:scrollArr } = this.state
this.state.heightArr.map((item, index) => {
if(scrollTop >= 0 && scrollTop < scrollArr[0]) {
// 第一个
this.setState({activeIndex: 0})
}
if(scrollTop >= scrollArr[index - 1] && scrollTop <= scrollArr[index]) {
// 第N个
this.setState({activeIndex: index})
}
})
}
render () {
const { activeStatus,activeIndex } = this.state
return (
<View className='index'>
<View className='tabList'>
{tabList.map((item, index) => (
<View onClick={this.handleTab.bind(this, item.value, index)} key={item.value} className={`tab-item ${index===activeIndex && 'active'}`}>{item.name}</View>
))}
</View>
<ScrollView style={{height: '400px'}} scrollY scrollWithAnimation scrollIntoView={activeStatus} onScroll={this.handleScroll.bind(this)}>
<View id='header'>
<View style={{height: '600px'}}>头</View>
</View>
<View id='content'>
<View style={{height: '150px'}}>内容</View>
</View>
<View id='footer'>
<View style={{height: '3000px'}}>底部</View>
</View>
</ScrollView>
</View>
)
}
}