使用

1. 索引列表主要由 scroll-view 标签实现，类名为 indexes，具体js逻辑请看源码

2. 我个人没有使用过这个，大家根据源码来看一下，我也有些地方没弄懂

<template>
	<view>
		<view class="cu-bar bg-white search fixed">
			<view class="search-form round">
				<text class="cuIcon-search"></text>
				<input type="text" placeholder="输入搜索的关键词" confirm-type="search"></input>
			</view>
			<view class="action">
				<button class="cu-btn bg-gradual-green shadow-blur round">搜索</button>
			</view>
		</view>
		<scroll-view scroll-y class="indexes" :scroll-into-view="'indexes-'+ listCurID" :style="[{height:'calc(100vh - 50px)'}]"
		 :scroll-with-animation="true" :enable-back-to-top="true">
			<block v-for="(item,index) in list" :key="index">
<!-- 这个'indexItem-' + item.name类名，整个colorUI，我也没找到它的作用，删了也没发现什么影响-->
				<view :class="'indexItem-' + item.name" :id="'indexes-' + item.name" :data-index="item.name">
					<view class="padding">{{item.name}}</view>
					<view class="cu-list menu-avatar no-padding">
						<view class="cu-item" v-for="(items,sub) in 2" :key="sub">
							<view class="cu-avatar round lg">{{item.name}}</view>
							<view class="content">
								<view class="text-grey">{{item.name}}<text class="text-abc">{{list[sub].name}}</text>君</view>
								<view class="text-gray text-sm">
									有{{sub+2}}个主子需要伺候
								</view>
							</view>
						</view>
					</view>
				</view>
			</block>
		</scroll-view>
		<view class="indexBar" :style="[{height:'calc(100vh - 50px)'}]">
			<view class="indexBar-box" @touchstart="tStart" @touchend="tEnd" @touchmove.stop="tMove">
				<view class="indexBar-item" v-for="(item,index) in list" :key="index" :id="index" @touchstart="getCur" @touchend="setCur">
					{{item.name}}</view>
			</view>
		</view>
		<!--选择显示-->
		<view v-show="!hidden" class="indexToast">
			{{listCur}}
		</view>
	</view>
</template>
 
<script>
	export default {
		data() {
			return {
				StatusBar: this.StatusBar,
				CustomBar: this.CustomBar,
				hidden: true,
				listCurID: '',
				list: [],
				listCur: '',
			};
		},
		onLoad() {
			let list = [{}];
			for (let i = 0; i < 26; i++) {
				list[i] = {};
				list[i].name = String.fromCharCode(65 + i);
			}
			this.list = list;
			this.listCur = list[0];
		},
		onReady() {
			let that = this;
			//这两句大概知道什么意思，但是emmm,这个boxTop和barTop具体是什么数值，不是很理解
			uni.createSelectorQuery().select('.indexBar-box').boundingClientRect(function(res) {
				that.boxTop = res.top
			}).exec();
			uni.createSelectorQuery().select('.indexes').boundingClientRect(function(res) {
				that.barTop = res.top
			}).exec()
		},
		methods: {
			//获取文字信息
			getCur(e) {
				this.hidden = false;
				this.listCur = this.list[e.target.id].name;
			},
			setCur(e) {
				this.hidden = true;
				this.listCur = this.listCur
			},
			//滑动选择Item
			tMove(e) {
				console.log(this.boxTop)
				let y = e.touches[0].clientY,
					offsettop = this.boxTop,
					that = this;
				//判断选择区域,只有在选择区才会生效
				if (y > offsettop) {
// 这个num计算结果怎么就是字母列表的下标呢，我没想明白，望大佬指教
					let num = parseInt((y - offsettop) / 20);
					this.listCur = that.list[num].name
				};
			},
 
			//触发全部开始选择
			tStart() {
				this.hidden = false
			},
 
			//触发结束选择
			tEnd() {
				this.hidden = true;
				this.listCurID = this.listCur
			},
//源码中有这个函数，但是这个页面中根本没有用到，删了没影响，我也不明白作者为什么写这个
			indexSelect(e) {
				let that = this;
				let barHeight = this.barHeight;
				let list = this.list;
				let scrollY = Math.ceil(list.length * e.detail.y / barHeight);
				for (let i = 0; i < list.length; i++) {
					if (scrollY < i + 1) {
						that.listCur = list[i].name;
						that.movableY = i * 20
						return false
					}
				}
			} 
		}
	}
</script>
 
<style>
	page {
		padding-top: 100upx;
	}
 
	.indexes {
		position: relative;
	}
 
	.indexBar {
		position: fixed;
		right: 0px;
		bottom: 0px;
		padding: 20upx 20upx 20upx 60upx;
		display: flex;
		align-items: center;
	}
 
	.indexBar .indexBar-box {
		width: 40upx;
		height: auto;
		background: #fff;
		display: flex;
		flex-direction: column;
		box-shadow: 0 0 20upx rgba(0, 0, 0, 0.1);
		border-radius: 10upx;
	}
 
	.indexBar-item {
		flex: 1;
		width: 40upx;
		height: 40upx;
		display: flex;
		align-items: center;
		justify-content: center;
		font-size: 24upx;
		color: #888;
	}
 
	movable-view.indexBar-item {
		width: 40upx;
		height: 40upx;
		z-index: 9;
		position: relative;
	}
 
	movable-view.indexBar-item::before {
		content: "";
		display: block;
		position: absolute;
		left: 0;
		top: 10upx;
		height: 20upx;
		width: 4upx;
		background-color: #f37b1d;
	}
 
	.indexToast {
		position: fixed;
		top: 0;
		right: 80upx;
		bottom: 0;
		background: rgba(0, 0, 0, 0.5);
		width: 100upx;
		height: 100upx;
		border-radius: 10upx;
		margin: auto;
		color: #fff;
		line-height: 100upx;
		text-align: center;
		font-size: 48upx;
	}
</style>