mechanicStore-app/uni_modules/uview-plus/components/u-tabs/u-tabs.vue

<template>
	<view class="u-tabs" :class="[customClass]">
		<view class="u-tabs__wrapper">
			<slot name="left" />
			<view class="u-tabs__wrapper__scroll-view-wrapper">
				<scroll-view :scroll-x="scrollable" :scroll-left="scrollLeft" scroll-with-animation
					class="u-tabs__wrapper__scroll-view" :show-scrollbar="false" ref="u-tabs__wrapper__scroll-view">
					<view class="u-tabs__wrapper__nav" ref="u-tabs__wrapper__nav">
						<view class="u-tabs__wrapper__nav__item" v-for="(item, index) in tabList" :key="index"
							@tap="clickHandler(item, index)" @longpress="longPressHandler(item,index)"
							:ref="`u-tabs__wrapper__nav__item-${index}`"
							:style="[addStyle(itemStyle), {flex: scrollable ? '' : 1}]" :class="[`u-tabs__wrapper__nav__item-${index}`,
								item.disabled && 'u-tabs__wrapper__nav__item--disabled',
								innerCurrent == index ? 'u-tabs__wrapper__nav__item-active' : '']">
							<slot v-if="$slots.icon" name="icon" :item="item" :keyName="keyName" :index="index" />
							<template v-else>
								<view class="u-tabs__wrapper__nav__item__prefix-icon" v-if="item.icon">
									<up-icon :name="item.icon" :customStyle="addStyle(iconStyle)"></up-icon>
								</view>
							</template>
							<slot v-if="$slots.content" name="content" :item="item" :keyName="keyName" :index="index" />
							<slot v-else-if="!$slots.content && ($slots.default || $slots.$default)" :item="item"
								:keyName="keyName" :index="index" />
							<text v-else :class="[item.disabled && 'u-tabs__wrapper__nav__item__text--disabled']"
								class="u-tabs__wrapper__nav__item__text"
								:style="[textStyle(index)]">{{ item[keyName] }}</text>
							<u-badge :show="!!(item.badge && (item.badge.show || item.badge.isDot || item.badge.value))"
								:isDot="item.badge && item.badge.isDot || propsBadge.isDot"
								:value="item.badge && item.badge.value || propsBadge.value"
								:max="item.badge && item.badge.max || propsBadge.max"
								:type="item.badge && item.badge.type || propsBadge.type"
								:showZero="item.badge && item.badge.showZero || propsBadge.showZero"
								:bgColor="item.badge && item.badge.bgColor || propsBadge.bgColor"
								:color="item.badge && item.badge.color || propsBadge.color"
								:shape="item.badge && item.badge.shape || propsBadge.shape"
								:numberType="item.badge && item.badge.numberType || propsBadge.numberType"
								:inverted="item.badge && item.badge.inverted || propsBadge.inverted"
								customStyle="margin-left: 4px;"></u-badge>
						</view>
						<!-- #ifdef APP-NVUE -->
						<view class="u-tabs__wrapper__nav__line" ref="u-tabs__wrapper__nav__line" :style="[{
								width: addUnit(lineWidth),
								height: addUnit(lineHeight),
								background: lineColor,
								backgroundSize: lineBgSize,
							}]">
						</view>
						<!-- #endif -->
						<!-- #ifndef APP-NVUE -->
						<view class="u-tabs__wrapper__nav__line" ref="u-tabs__wrapper__nav__line"
							:style="[{
								width: addUnit(lineWidth),
								transform: `translate(${lineOffsetLeft}px)`,
								transitionDuration: `${duration}ms`,
								height: addUnit(lineHeight),
								background: lineColor,
								backgroundSize: lineBgSize,
								display: lineShow ? 'block': 'none'
							}]">
						</view>
						<!-- #endif -->
					</view>
				</scroll-view>
			</view>
			<slot name="right" />
		</view>
	</view>
</template>

<script>
	// #ifdef APP-NVUE
	const animation = uni.requireNativePlugin('animation')
	const dom = uni.requireNativePlugin('dom')
	// #endif
	import {
		props
	} from './props';
	import {
		mpMixin
	} from '../../libs/mixin/mpMixin';
	import {
		mixin
	} from '../../libs/mixin/mixin';
	import defProps from '../../libs/config/props.js'
	import {
		addUnit,
		addStyle,
		deepMerge,
		deepClone,
		getPx,
		sleep,
		getWindowInfo
	} from '../../libs/function/index';
	/**
	 * Tabs 标签
	 * @description tabs标签组件，在标签多的时候，可以配置为左右滑动，标签少的时候，可以禁止滑动。 该组件的一个特点是配置为滚动模式时，激活的tab会自动移动到组件的中间位置。
	 * @tutorial https://uview-plus.jiangruyi.com/components/tabs.html
	 * @property {String | Number}	duration			滑块移动一次所需的时间，单位秒（默认 200 ）
	 * @property {String | Number}	swierWidth			swiper的宽度（默认 '750rpx' ）
	 * @property {String}	keyName	 从`list`元素对象中读取的键名（默认 'name' ）
	 * @event {Function(index)} change 标签改变时触发 index: 点击了第几个tab，索引从0开始
	 * @event {Function(index)} click 点击标签时触发 index: 点击了第几个tab，索引从0开始
	 * @event {Function(index)} longPress 长按标签时触发 index: 点击了第几个tab，索引从0开始
	 * @example <u-tabs :list="list" :is-scroll="false" :current="current" @change="change" @longPress="longPress"></u-tabs>
	 */
	export default {
		name: 'u-tabs',
		mixins: [mpMixin, mixin, props],
		data() {
			return {
				tabList: [],
				scrollLeft: 0,
				scrollViewWidth: 0,
				lineOffsetLeft: 0,
				lineShow: false,
				tabsRect: {
					left: 0
				},
				innerCurrent: 0,
				moving: false,
			}
		},
		watch: {
			current: {
				immediate: true,
				handler(newValue, oldValue) {
					// 内外部值不相等时，才尝试移动滑块
					if (newValue !== this.innerCurrent) {
						if (typeof newValue == 'string') {
							this.innerCurrent = parseInt(newValue)
						} else {
							this.innerCurrent = newValue
						}
						this.$nextTick(() => {
							this.resize()
						})
					}
				}
			},
			// list变化时，重新渲染list各项信息
			list: {
				handler(newValue, oldValue) {
					// 重新拷贝一份list用于增加其他额外信息处理后导致重复监听的死循环
					this.tabList = deepClone(newValue);
					this.$nextTick(() => {
						this.resize()
					})
				},
				immediate: true,
				deep: true,
			}
		},
		computed: {
			textStyle() {
				return index => {
					const style = {}
					// 取当期是否激活的样式
					const customeStyle = (index == this.innerCurrent) ?
						addStyle(this.activeStyle) :
						addStyle(this.inactiveStyle)
					// 如果当前菜单被禁用，则加上对应颜色，需要在此做处理，是因为nvue下，无法在style样式中通过!import覆盖标签的内联样式
					if (this.tabList[index].disabled) {
						style.color = '#c8c9cc'
					}
					return deepMerge(customeStyle, style)
				}
			},
			propsBadge() {
				return defProps.badge
			}
		},
		async mounted() {
			this.init()
			this.windowResizeCallback = (res) => {
				this.init()
			}
			uni.onWindowResize(this.windowResizeCallback)
		},
		beforeUnmount() {
			uni.offWindowResize(this.windowResizeCallback)
		},
		emits: ['click', 'longPress', 'change', 'update:current'],
		methods: {
			addStyle,
			addUnit,
			setLineLeft() {
				const tabItem = this.tabList[this.innerCurrent];
				if (!tabItem) {
					return;
				}
				// 获取滑块该移动的位置
				let lineOffsetLeft = this.tabList
					.slice(0, this.innerCurrent)
					.reduce((total, curr) => total + curr.rect.width, 0);
				// 获取下划线的数值px表示法
				const lineWidth = getPx(this.lineWidth);
				this.lineOffsetLeft = lineOffsetLeft + (tabItem.rect.width - lineWidth) / 2
				// #ifdef APP-NVUE
				// 第一次移动滑块，无需过渡时间
				this.animation(this.lineOffsetLeft, parseInt(this.duration))
				// #endif

				// 如果是第一次执行此方法，滑块默认不显示，在加载完成后进行显示
				if (!this.lineShow) this.lineShow = true;
			},
			// nvue下设置滑块的位置
			animation(x, duration = 0) {
				// #ifdef APP-NVUE
				const ref = this.$refs['u-tabs__wrapper__nav__line']
				animation.transition(ref, {
					styles: {
						transform: `translateX(${x}px)`
					},
					duration
				})
				// #endif
			},
			// 点击某一个标签
			clickHandler(item, index) {
				// 因为标签可能为disabled状态，所以click是一定会发出的，但是change事件是需要可用的状态才发出
				this.$emit('click', {
					...item,
					index
				}, index)
				// 如果disabled状态，返回
				if (item.disabled) return
				// 如果点击当前不触发change
				if (this.innerCurrent == index) return
				this.innerCurrent = index
				this.$nextTick(() => {
					this.resize()
				})
				this.$emit('update:current', index)
				this.$emit('change', {
					...item,
					index
				}, index)
			},
			// 长按事件
			longPressHandler(item, index) {
				this.$emit('longPress', {
					...item,
					index
				})
			},
			init() {
				sleep().then(() => {
					this.resize()
				})
			},
			setScrollLeft() {
				// 当前活动tab的布局信息，有tab菜单的width和left(为元素左边界到父元素左边界的距离)等信息
				if (this.innerCurrent < 0) {
					this.innerCurrent = 0;
				}
				const tabRect = this.tabList[this.innerCurrent]
				// 累加得到当前item到左边的距离
				const offsetLeft = this.tabList
					.slice(0, this.innerCurrent)
					.reduce((total, curr) => {
						return total + curr.rect.width
					}, 0)
				// 此处为屏幕宽度
				const windowWidth = getWindowInfo().windowWidth
				// 将活动的tabs-item移动到屏幕正中间，实际上是对scroll-view的移动
				let scrollLeft = offsetLeft - (this.tabsRect.width - tabRect.rect.width) / 2 - (windowWidth - this.tabsRect
					.right) / 2 + this.tabsRect.left / 2
				// 这里做一个限制，限制scrollLeft的最大值为整个scroll-view宽度减去tabs组件的宽度
				scrollLeft = Math.min(scrollLeft, this.scrollViewWidth - this.tabsRect.width)
				this.scrollLeft = Math.max(0, scrollLeft)
			},
			// 获取所有标签的尺寸
			resize() {
				// 如果不存在list，则不处理
				if (this.tabList.length === 0) {
					return
				}
				Promise.all([this.getTabsRect(), this.getAllItemRect()]).then(([tabsRect, itemRect = []]) => {
					// 兼容在swiper组件中使用
					if (tabsRect.left > tabsRect.width) {
						tabsRect.right = tabsRect.right - Math.floor(tabsRect.left / tabsRect.width) * tabsRect
							.width
						tabsRect.left = tabsRect.left % tabsRect.width
					}
					// console.log(tabsRect)
					this.tabsRect = tabsRect
					this.scrollViewWidth = 0
					itemRect.map((item, index) => {
						// 计算scroll-view的宽度，这里
						this.scrollViewWidth += item.width
						// 另外计算每一个item的中心点X轴坐标
						this.tabList[index].rect = item
					})
					// 获取了tabs的尺寸之后，设置滑块的位置
					this.setLineLeft()
					this.setScrollLeft()
				})
			},
			// 获取导航菜单的尺寸
			getTabsRect() {
				return new Promise(resolve => {
					this.queryRect('u-tabs__wrapper__scroll-view').then(size => resolve(size))
				})
			},
			// 获取所有标签的尺寸
			getAllItemRect() {
				return new Promise(resolve => {
					const promiseAllArr = this.tabList.map((item, index) => this.queryRect(
						`u-tabs__wrapper__nav__item-${index}`, true));
					Promise.all(promiseAllArr).then(sizes => resolve(sizes));
				})
			},
			// 获取各个标签的尺寸
			queryRect(el, item) {
				// #ifndef APP-NVUE
				// $uGetRect为uView自带的节点查询简化方法，详见文档介绍：https://uview-plus.jiangruyi.com/js/getRect.html
				// 组件内部一般用this.$uGetRect，对外的为uni.$u.getRect，二者功能一致，名称不同
				return new Promise(resolve => {
					this.$uGetRect(`.${el}`).then(size => {
						resolve(size)
					})
				})
				// #endif

				// #ifdef APP-NVUE
				// nvue下，使用dom模块查询元素高度
				// 返回一个promise，让调用此方法的主体能使用then回调
				return new Promise(resolve => {
					dom.getComponentRect(item ? this.$refs[el][0] : this.$refs[el], res => {
						resolve(res.size)
					})
				})
				// #endif
			},
		},
	}
</script>

<style lang="scss" scoped>
	.u-tabs {

		&__wrapper {
			@include flex;
			align-items: center;

			&__scroll-view-wrapper {
				flex: 1;
				/* #ifndef APP-NVUE */
				overflow: auto hidden;
				/* #endif */
			}

			&__scroll-view {
				@include flex;
				flex: 1;
			}

			&__nav {
				@include flex;
				position: relative;

				&__item {
					padding: 0 11px;
					@include flex;
					align-items: center;
					justify-content: center;
					/* #ifdef H5 */
					cursor: pointer;
					/* #endif */

					&--disabled {
						/* #ifdef H5 */
						cursor: not-allowed;
						/* #endif */
					}

					&__text {
						font-size: 15px;
						color: $u-content-color;
						white-space: nowrap !important;

						&--disabled {
							color: $u-disabled-color !important;
						}
					}
				}

				&__line {
					height: 3px;
					background: $u-primary;
					width: 30px;
					position: absolute;
					bottom: 2px;
					border-radius: 100px;
					transition-property: transform;
					transition-duration: 300ms;
				}
			}
		}
	}
</style>