<template>
 <div class="container">
 <w-f-column itemW="200">
 <template slot-scope="{columnNum,columnIndex}">
 <water-follow :list="list" :columnNum="columnNum" :columnIndex="columnIndex">
 <template slot-scope="{item,index}">
 <div class="my-box" :style="{height:item+'px'}">{{item}}-{{index}}</div>
 </template>
 </water-follow>
 </template>
 </w-f-column>
 </div>
</template>

<script>
import WFColumn from '../waterFollow/WFColumn'
import WaterFollow from '../waterFollow/WaterFollow'
export default {
 name: 'page',
 components: {WaterFollow, WFColumn},
 data () {
 return {
 list: []
 }
 },
 created () {
 // 有初始數(shù)據(jù)
 for (let i = 0; i < 50; i++) {
 this.list.push(Math.floor(Math.random() * 301 + 200))
 }
 },
 mounted () {
 // 模擬網(wǎng)絡(luò)請求
 // window.setTimeout(() => {
 // this.list = []
 // for (let i = 0; i < 50; i++) {
 // this.list.push(Math.floor(Math.random() * 301 + 200))
 // }
 // }, 1000)
 // -- 分割 --
 // 模擬數(shù)據(jù)不斷變化
 // window.setInterval(() => {
 // this.list = []
 // for (let i = 0; i < 50; i++) {
 // this.list.push(Math.floor(Math.random() * 301 + 200))
 // }
 // }, 1000)
 }
}
</script>

<style scoped lang="scss">
 .container{
 width: 100%;
 background: gray;
 .my-box{
 width: 200px;
 background: #000;
 margin-bottom: 20px;
 color: #fff;
 }
 }
</style>

<template>
 <div class="wf-container">
 <div class="wf-column" v-for="(item,index) in columnNum" :key="'column-'+index" :name="index">
 <slot :columnNum="columnNum" :columnIndex="index"></slot>
 </div>
 </div>
</template>

<script>
export default {
 name: 'WFColumn',
 props: ['itemW'],
 data () {
 return {
 columnNum: 0
 }
 },
 created () {
 this.columnNum = Math.floor(document.body.clientWidth / this.itemW)
 window.onresize = () => {
 this.columnNum = Math.floor(document.body.clientWidth / this.itemW)
 }
 }
}
</script>

<style scoped lang="scss">
.wf-container{
 width: 100%;
 display: flex;
 .wf-column{
 flex: 1;
 }
}
</style>

<template>
 <div>
 <div v-for="(item,index) in list" :key="'item-'+index" class="item" :id="'card-'+columnIndex+'-'+index" v-if="load?(record[index].index===columnIndex):true">
 <slot :item="item" :index="index"></slot>
 </div>
 </div>
</template>

<script>
export default {
 name: 'WaterFollow',
 props: ['list', 'columnNum', 'columnIndex'],
 data () {
 return {
 column: 0,
 record: [],
 load: false,
 update: false
 }
 },
 methods: {
 calculateColumn () {
 let cList = []
 for (let i = 0; i < this.columnNum; i++) {
 cList.push(0)
 }
 for (let i = 0; i < this.record.length; i++) {
 let index = 0
 for (let j = 0; j < cList.length; j++) {
 if (cList[index] > cList[j]) {
 index = j
 }
 }
 cList[index] += this.record[i].height
 this.record[i].index = index
 }
 },
 recordInit () {
 for (let i = 0; i < this.list.length; i++) {
 this.record.push({index: -1, height: -1})
 }
 },
 initHeightData () {
 for (let i = 0; i < this.list.length; i++) {
 if (document.getElementById('card-' + this.columnIndex + '-' + i)) {
 let h = document.getElementById('card-' + this.columnIndex + '-' + i).offsetHeight
 this.record[i].height = h
 }
 }
 }
 },
 beforeCreate () {},
 created () {
 this.load = false
 this.recordInit()
 },
 beforeMount () {},
 mounted () {
 this.initHeightData()
 this.calculateColumn()
 this.load = true
 },
 beforeUpdate () {},
 updated () {
 if (this.update) {
 this.initHeightData()
 this.calculateColumn()
 this.update = false
 this.load = true
 }
 },
 beforeDestroy () {},
 destroyed () {},
 watch: {
 columnNum (curr, old) {
 this.calculateColumn()
 },
 list (curr, old) {
 console.log('list change')
 this.recordInit()
 this.load = false
 this.update = true
 }
 }
}
</script>

<style scoped>
</style>