<template>
<div>
<div id="app">
<button @click="add">增加</button>
<div class="container" ref="container">
<div class="scroll-wrapper" :style="style">
<div v-for="(item, index) in scrollList" :key="index" class="item">{{ item }}</div>
</div>
</div>
</div>
</div>
</template>
<script>
export default {
data() {
return {
list: ['测试数据'],
startIndex: 0,
endIndex: 60,
paddingTop: 0,
paddingBottom: 0,
allHeight: 0
}
},
props: {
value: {
type: Boolean,
default: false
}
},
computed: {
scrollList() {
console.log(this.startIndex, this.endIndex)
return this.list.slice(this.startIndex, this.endIndex)
},
style() {
return {
paddingTop: this.paddingTop + 'px',
paddingBottom: this.paddingBottom + 'px'
}
}
},
watch: {
list(val) {
const valLen = val.length
this.allHeight = valLen * 30
this.paddingBottom = this.allHeight - this.scrollList.length * 30
}
},
mounted() {
const container = this.$refs.container
container.addEventListener('scroll', () => {
const top = container.scrollTop
this.startIndex = Math.floor(top / 30)
this.endIndex = this.startIndex + 60
console.log('top', top)
this.paddingTop = top
if (this.endIndex >= this.list.length - 1) {
this.paddingBottom = 0
return
}
this.paddingBottom = this.allHeight - 600 - top
})
},
methods: {
add() {
let arr = new Array(50000).fill(0)
arr = arr.map((item, index) => {
return index
})
this.list = [...this.list, ...arr]
}
}
}
</script>
<style scoped>
.container {
width: 300px;
height: 600px;
overflow: auto;
border: 1px solid;
margin: 100px auto;
}
.item {
height: 29px;
line-height: 30px;
border-bottom: 1px solid #aaa;
padding-left: 20px;
}
</style>
