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<template>
<!-- 支付宝小程序使用$u.getRect()获取组件的根元素尺寸所以在外面套一个"壳" -->
<view>
<view class="u-index-bar">
<slot />
<view v-if="showSidebar" class="u-index-bar__sidebar" @touchstart.stop.prevent="onTouchMove" @touchmove.stop.prevent="onTouchMove"
@touchend.stop.prevent="onTouchStop" @touchcancel.stop.prevent="onTouchStop">
<view v-for="(item, index) in indexList" :key="index" class="u-index-bar__index" :style="{zIndex: zIndex + 1, color: activeAnchorIndex === index ? activeColor : ''}"
:data-index="index">
{{ item }}
</view>
</view>
<view class="u-indexed-list-alert" v-if="touchmove && indexList[touchmoveIndex]" :style="{
zIndex: alertZIndex
}">
<text>{{indexList[touchmoveIndex]}}</text>
</view>
</view>
</view>
</template>
<script>
var indexList = function() {
var indexList = [];
var charCodeOfA = 'A'.charCodeAt(0);
for (var i = 0; i < 26; i++) {
indexList.push(String.fromCharCode(charCodeOfA + i));
}
return indexList;
};
/**
* indexList 索引列表
* @description 通过折叠面板收纳内容区域,搭配<u-index-anchor>使用
* @tutorial https://www.uviewui.com/components/indexList.html#indexanchor-props
* @property {Number String} scroll-top 当前滚动高度自定义组件无法获得滚动条事件所以依赖接入方传入
* @property {Array} index-list 索引字符列表数组默认A-Z
* @property {Number String} z-index 锚点吸顶时的层级默认965
* @property {Boolean} sticky 是否开启锚点自动吸顶默认true
* @property {Number String} offset-top 锚点自动吸顶时与顶部的距离默认0
* @property {String} highlight-color 锚点和右边索引字符高亮颜色默认#2979ff
* @event {Function} select 选中右边索引字符时触发
* @example <u-index-list :scrollTop="scrollTop"></u-index-list>
*/
export default {
name: "u-index-list",
props: {
sticky: {
type: Boolean,
default: true
},
zIndex: {
type: [Number, String],
default: ''
},
scrollTop: {
type: [Number, String],
default: 0,
},
offsetTop: {
type: [Number, String],
default: 0
},
indexList: {
type: Array,
default () {
return indexList()
}
},
activeColor: {
type: String,
default: '#2979ff'
}
},
created() {
// #ifdef H5
this.stickyOffsetTop = this.offsetTop ? uni.upx2px(this.offsetTop) : 44;
// #endif
// #ifndef H5
this.stickyOffsetTop = this.offsetTop ? uni.upx2px(this.offsetTop) : 0;
// #endif
// 只能在created生命周期定义children,如果在data定义,会因为循环引用而报错
this.children = [];
},
data() {
return {
activeAnchorIndex: 0,
showSidebar: true,
// children: [],
touchmove: false,
touchmoveIndex: 0,
}
},
watch: {
scrollTop() {
this.updateData()
}
},
computed: {
// 弹出toast的z-index值
alertZIndex() {
return this.$u.zIndex.toast;
}
},
methods: {
updateData() {
this.timer && clearTimeout(this.timer);
this.timer = setTimeout(() => {
this.showSidebar = !!this.children.length;
this.setRect().then(() => {
this.onScroll();
});
}, 0);
},
setRect() {
return Promise.all([
this.setAnchorsRect(),
this.setListRect(),
this.setSiderbarRect()
]);
},
setAnchorsRect() {
return Promise.all(this.children.map((anchor, index) => anchor
.$uGetRect('.u-index-anchor-wrapper')
.then((rect) => {
Object.assign(anchor, {
height: rect.height,
top: rect.top
});
})));
},
setListRect() {
return this.$uGetRect('.u-index-bar').then((rect) => {
Object.assign(this, {
height: rect.height,
top: rect.top + this.scrollTop
});
});
},
setSiderbarRect() {
return this.$uGetRect('.u-index-bar__sidebar').then(rect => {
this.sidebar = {
height: rect.height,
top: rect.top
};
});
},
getActiveAnchorIndex() {
const {
children
} = this;
const {
sticky
} = this;
for (let i = this.children.length - 1; i >= 0; i--) {
const preAnchorHeight = i > 0 ? children[i - 1].height : 0;
const reachTop = sticky ? preAnchorHeight : 0;
if (reachTop >= children[i].top) {
return i;
}
}
return -1;
},
onScroll() {
const {
children = []
} = this;
if (!children.length) {
return;
}
const {
sticky,
stickyOffsetTop,
zIndex,
scrollTop,
activeColor
} = this;
const active = this.getActiveAnchorIndex();
this.activeAnchorIndex = active;
if (sticky) {
let isActiveAnchorSticky = false;
if (active !== -1) {
isActiveAnchorSticky =
children[active].top <= 0;
}
children.forEach((item, index) => {
if (index === active) {
let wrapperStyle = '';
let anchorStyle = {
color: `${activeColor}`
};
if (isActiveAnchorSticky) {
wrapperStyle = {
height: `${children[index].height}px`
};
anchorStyle = {
position: 'fixed',
top: `${stickyOffsetTop}px`,
zIndex: `${zIndex ? zIndex : this.$u.zIndex.indexListSticky}`,
color: `${activeColor}`
};
}
item.active = active;
item.wrapperStyle = wrapperStyle;
item.anchorStyle = anchorStyle;
} else if (index === active - 1) {
const currentAnchor = children[index];
const currentOffsetTop = currentAnchor.top;
const targetOffsetTop = index === children.length - 1 ?
this.top :
children[index + 1].top;
const parentOffsetHeight = targetOffsetTop - currentOffsetTop;
const translateY = parentOffsetHeight - currentAnchor.height;
const anchorStyle = {
position: 'relative',
transform: `translate3d(0, ${translateY}px, 0)`,
zIndex: `${zIndex ? zIndex : this.$u.zIndex.indexListSticky}`,
color: `${activeColor}`
};
item.active = active;
item.anchorStyle = anchorStyle;
} else {
item.active = false;
item.anchorStyle = '';
item.wrapperStyle = '';
}
});
}
},
onTouchMove(event) {
this.touchmove = true;
const sidebarLength = this.children.length;
const touch = event.touches[0];
const itemHeight = this.sidebar.height / sidebarLength;
let clientY = 0;
clientY = touch.clientY;
let index = Math.floor((clientY - this.sidebar.top) / itemHeight);
if (index < 0) {
index = 0;
} else if (index > sidebarLength - 1) {
index = sidebarLength - 1;
}
this.touchmoveIndex = index;
this.scrollToAnchor(index);
},
onTouchStop() {
this.touchmove = false;
this.scrollToAnchorIndex = null;
},
scrollToAnchor(index) {
if (this.scrollToAnchorIndex === index) {
return;
}
this.scrollToAnchorIndex = index;
const anchor = this.children.find((item) => item.index === this.indexList[index]);
if (anchor) {
this.$emit('select', anchor.index);
uni.pageScrollTo({
duration: 0,
scrollTop: anchor.top + this.scrollTop
});
}
}
}
};
</script>
<style lang="scss" scoped>
@import "../../libs/css/style.components.scss";
.u-index-bar {
position: relative
}
.u-index-bar__sidebar {
position: fixed;
top: 50%;
right: 0;
@include vue-flex;
flex-direction: column;
text-align: center;
transform: translateY(-50%);
user-select: none;
z-index: 99;
}
.u-index-bar__index {
font-weight: 500;
padding: 8rpx 18rpx;
font-size: 22rpx;
line-height: 1
}
.u-indexed-list-alert {
position: fixed;
width: 120rpx;
height: 120rpx;
right: 90rpx;
top: 50%;
margin-top: -60rpx;
border-radius: 24rpx;
font-size: 50rpx;
color: #fff;
background-color: rgba(0, 0, 0, 0.65);
@include vue-flex;
justify-content: center;
align-items: center;
padding: 0;
z-index: 9999999;
}
.u-indexed-list-alert text {
line-height: 50rpx;
}
</style>