| <template> | |
| 	<u-transition | |
| 	    mode="fade" | |
| 	    :customStyle="backTopStyle" | |
| 	    :show="show" | |
| 	> | |
| 		<view | |
| 		    class="u-back-top" | |
| 			:style="[contentStyle]" | |
| 		    v-if="!$slots.default && !$slots.$default" | |
| 			@click="backToTop" | |
| 		> | |
| 			<u-icon | |
| 			    :name="icon" | |
| 			    :custom-style="iconStyle" | |
| 			></u-icon> | |
| 			<text | |
| 			    v-if="text" | |
| 			    class="u-back-top__text" | |
| 			>{{text}}</text> | |
| 		</view> | |
| 		<slot v-else /> | |
| 	</u-transition> | |
| </template> | |
|  | |
| <script> | |
| 	import props from './props.js'; | |
| 	// #ifdef APP-NVUE | |
| 	const dom = weex.requireModule('dom') | |
| 	// #endif | |
| 	/** | |
| 	 * backTop 返回顶部 | |
| 	 * @description 本组件一个用于长页面,滑动一定距离后,出现返回顶部按钮,方便快速返回顶部的场景。 | |
| 	 * @tutorial https://uviewui.com/components/backTop.html | |
| 	 *  | |
| 	 * @property {String}			mode  		返回顶部的形状,circle-圆形,square-方形 (默认 'circle' ) | |
| 	 * @property {String} 			icon 		自定义图标 (默认 'arrow-upward' ) 见官方文档示例 | |
| 	 * @property {String} 			text 		提示文字  | |
| 	 * @property {String | Number}  duration	返回顶部滚动时间 (默认 100) | |
| 	 * @property {String | Number}  scrollTop	滚动距离 (默认 0 ) | |
| 	 * @property {String | Number}  top  		距离顶部多少距离显示,单位px (默认 400 ) | |
| 	 * @property {String | Number}  bottom  	返回顶部按钮到底部的距离,单位px (默认 100 ) | |
| 	 * @property {String | Number}  right  		返回顶部按钮到右边的距离,单位px (默认 20 ) | |
| 	 * @property {String | Number}  zIndex 		层级   (默认 9 ) | |
| 	 * @property {Object<Object>}  	iconStyle 	图标的样式,对象形式   (默认 {color: '#909399',fontSize: '19px'}) | |
| 	 * @property {Object}			customStyle	定义需要用到的外部样式 | |
| 	 *  | |
| 	 * @example <u-back-top :scrollTop="scrollTop"></u-back-top> | |
| 	 */ | |
| 	export default { | |
| 		name: 'u-back-top', | |
| 		mixins: [uni.$u.mpMixin, uni.$u.mixin,props], | |
| 		computed: { | |
| 			backTopStyle() { | |
| 				// 动画组件样式 | |
| 				const style = { | |
| 					bottom: uni.$u.addUnit(this.bottom), | |
| 					right: uni.$u.addUnit(this.right), | |
| 					width: '40px', | |
| 					height: '40px', | |
| 					position: 'fixed', | |
| 					zIndex: 10, | |
| 				} | |
| 				return style | |
| 			}, | |
| 			show() { | |
| 				return uni.$u.getPx(this.scrollTop) > uni.$u.getPx(this.top) | |
| 			}, | |
| 			contentStyle() { | |
| 				const style = {} | |
| 				let radius = 0 | |
| 				// 是否圆形 | |
| 				if(this.mode === 'circle') { | |
| 					radius = '100px' | |
| 				} else { | |
| 					radius = '4px' | |
| 				} | |
| 				// 为了兼容安卓nvue,只能这么分开写 | |
| 				style.borderTopLeftRadius = radius | |
| 				style.borderTopRightRadius = radius | |
| 				style.borderBottomLeftRadius = radius | |
| 				style.borderBottomRightRadius = radius | |
| 				return uni.$u.deepMerge(style, uni.$u.addStyle(this.customStyle)) | |
| 			} | |
| 		}, | |
| 		methods: { | |
| 			backToTop() { | |
| 				// #ifdef APP-NVUE | |
| 				if (!this.$parent.$refs['u-back-top']) { | |
| 					uni.$u.error(`nvue页面需要给页面最外层元素设置"ref='u-back-top'`) | |
| 				} | |
| 				dom.scrollToElement(this.$parent.$refs['u-back-top'], { | |
| 					offset: 0 | |
| 				}) | |
| 				// #endif | |
| 				 | |
| 				// #ifndef APP-NVUE | |
| 				uni.pageScrollTo({ | |
| 					scrollTop: 0, | |
| 					duration: this.duration | |
| 				}); | |
| 				// #endif | |
| 				this.$emit('click') | |
| 			} | |
| 		} | |
| 	} | |
| </script> | |
| 
 | |
| <style lang="scss" scoped> | |
| 	@import '../../libs/css/components.scss'; | |
|      $u-back-top-flex:1 !default; | |
|      $u-back-top-height:100% !default; | |
|      $u-back-top-background-color:#E1E1E1 !default; | |
|      $u-back-top-tips-font-size:12px !default; | |
| 	.u-back-top { | |
| 		@include flex; | |
| 		flex-direction: column; | |
| 		align-items: center; | |
| 		flex:$u-back-top-flex; | |
| 		height: $u-back-top-height; | |
| 		justify-content: center; | |
| 		background-color: $u-back-top-background-color; | |
| 
 | |
| 		&__tips { | |
| 			font-size:$u-back-top-tips-font-size; | |
| 			transform: scale(0.8); | |
| 		} | |
| 	} | |
| </style>
 |