<template>
<view class="swiper-list">
<scroll-view ref="tabScroll" class="swiper-tabs" direction="horizontal" :show-scrollbar="false">
<view class="flex-row">
<text ref="swipertab" space="nbsp" class="swiper-tabs-item"
:class="swiperIndex==index ? 'swiper-tabs-item-active' : ''" v-for="(item, index) in swiperList" :key="index"
@click="onTabClick(index)">
{{item.title}}
</text>
</view>
<view ref="indicator" class="swiper-tabs-indicator"></view>
</scroll-view>
<swiper ref="swiper" class="swiper-view" :current="swiperIndex" @transition="onSwiperTransition"
@animationfinish="onSwiperAnimationfinish">
<swiper-item class="swiper-item" v-for="(_, index) in swiperList" :key="index">
<text class="uni-title">显示当前value</text>
<slider :value="50" :show-value="true" />
<text class="uni-title">设置步进:step=10跳动</text>
<slider :value="60" :step="10" />
<text class="uni-title">浮点步进:step=0.01跳动</text>
<slider :value="0.5" :min="0" :max="1" :step="0.01" :show-value="true" />
<text class="uni-title">设置最小/最大值</text>
<slider :value="100" :min="50" :max="200" :show-value="true" />
<text class="uni-title">不同颜色和大小的滑块</text>
<slider id="slider-custom-color-and-size" :value="sliderValue" :backgroundColor="sliderBackgroundColor"
:activeColor="sliderActiveColor" :activeBackgroundColor="sliderActiveColor" :blockColor="sliderBlockColor"
:foreColor="sliderBlockColor" :block-size="sliderBlockSize" />
</swiper-item>
</swiper>
</view>
</template>
<script>
type SwiperTabsItem = {
x : number,
w : number
}
type SwiperViewItem = {
title : string,
}
/**
* 根据权重在两个值之间执行线性插值.
* @constructor
* @param {number} value1 - 第一个值，该值应为下限.
* @param {number} value2 - 第二个值，该值应为上限.
* @param {number} amount - 应介于 0 和 1 之间，指示内插的权重.
* @returns {number} 内插值
*/
function lerpNumber(value1 : number, value2 : number, amount : number) : number {
return (value1 + (value2 - value1) * amount)
}
export default {
data() {
return {
swiperList: [] as SwiperViewItem[],
swiperIndex: 0,
tabScrollView: null as null | UniElement,
indicatorNode: null as null | UniElement,
animationFinishIndex: 0,
swiperWidth: 0,
swiperTabsRect: [] as SwiperTabsItem[],
sliderValue: 50,
sliderBlockSize: 20,
sliderBackgroundColor: "#000000",
sliderActiveColor: "#FFCC33",
sliderBlockColor: "#8A6DE9",
}
},
onLoad() {
// 初始化 5 个页签，宽度依次递增，用于演示在滑动 swiper 过程中指示线宽度的线性变化
for (let i = 0; i < 3; i++) {
const space = " ".repeat(i)
this.swiperList.push({
title: "Tab " + space + i
} as SwiperViewItem)
}
},
onReady() {
this.tabScrollView = this.$refs['tabScroll'] as UniElement;
this.indicatorNode = this.$refs['indicator'] as UniElement;
(this.$refs["swiper"] as UniElement).getBoundingClientRectAsync()!.then((res : DOMRect) : Promise<void> => {
this.swiperWidth = res.width
return this.cacheTabItemsSize()
}).then(() => {
this.updateTabIndicator(this.swiperIndex, this.swiperIndex, 1)
});
},
methods: {
/**
* 每个页签的点击事件，点击后设置当前 swiper.
* @constructor
* @param {number} index - 当前索引，该值应介于 0 和 最大数量之间.
*/
onTabClick(index : number) {
this.setSwiperIndex(index, false)
},
onSwiperTransition(e : SwiperTransitionEvent) {
// 微信 skyline 每项完成触发 Animationfinish，偏移值重置
// 微信 webview 全部完成触发 Animationfinish，偏移值累加
// 在滑动到下一个项的过程中，再次反向滑动，偏移值递减
// uni-app-x 和 微信 webview 行为一致
const offset_x = e.detail.dx
// 计算当前索引并重置差异
const current_offset_x = offset_x % this.swiperWidth
const current_offset_i = offset_x / this.swiperWidth
const current_index = this.animationFinishIndex + parseInt(current_offset_i + '')
// 计算目标索引及边界检查
let move_to_index = current_index
if (current_offset_x > 0 && move_to_index < this.swiperList.length - 1) {
move_to_index += 1
} else if (current_offset_x < 0 && move_to_index > 0) {
move_to_index -= 1
}
// 计算偏移百分比
const percentage = Math.abs(current_offset_x) / this.swiperWidth
// 通知更新指示线
if (current_index != move_to_index) {
this.updateTabIndicator(current_index, move_to_index, percentage)
}
},
/**
* Swiper滑动动画结束事件.
*/
onSwiperAnimationfinish(e : SwiperAnimationFinishEvent) {
this.setSwiperIndex(e.detail.current, true)
// 记录上次的索引位置
this.animationFinishIndex = e.detail.current
},
/**
* 缓存所有页签的左边距和宽度，用于计算指示线在移动过程中的线性变化.
*/
async cacheTabItemsSize() {
this.swiperTabsRect.length = 0;
const tabs = this.$refs["swipertab"] as UniElement[]
for (let i = 0; i < tabs.length; i++) {
const element = tabs[i];
// #ifdef MP
const rect = await element.getBoundingClientRectAsync()!
const x = rect.left
const w = rect.width
// #endif
// #ifndef MP
const x = element.offsetLeft
const w = element.offsetWidth
// #endif
this.swiperTabsRect.push({
x,
w
} as SwiperTabsItem)
}
},
/**
* 设置当前 swiper 选中的索引值.
* @constructor
* @param {number} index - 当前索引，该值应介于 0 和 最大数量之间.
* @param {boolean} updateIndicator - 是否更新指示线.
*/
setSwiperIndex(index : number, updateIndicator : boolean) {
if (this.swiperIndex === index) {
return
}
this.swiperIndex = index
if (updateIndicator) {
this.updateTabIndicator(index, index, 1)
}
},
/**
* 更新页签指示线的位置和宽度.
* @constructor
* @param {number} current_index - 当前索引，该值应介于 0 和 最大数量之间.
* @param {number} move_to_index - 目标索引，该值应介于 0 和 最大数量之间.
* @param {number} percentage - 偏移百分比，应介于 0 和 1 之间，用于计算在移动过程中的线性值.
*/
updateTabIndicator(current_index : number, move_to_index : number, percentage : number) {
const current_size = this.swiperTabsRect[current_index]
const move_to_size = this.swiperTabsRect[move_to_index]
// 计算指示线 位置 和 宽度 在移动过程中的线性值
const indicator_line_x = lerpNumber(current_size.x, move_to_size.x, percentage)
const indicator_line_w = lerpNumber(current_size.w, move_to_size.w, percentage)
// 通过 transform 更新指示线，避免重排版
// #ifdef APP
const x = indicator_line_x + indicator_line_w / 2
this.indicatorNode?.style?.setProperty('transform', `translateX(${x}px) scaleX(${indicator_line_w})`)
// #endif
// #ifdef WEB || MP
// TODO chrome windows系统 transform scaleX渲染bug
const x = indicator_line_x
this.indicatorNode?.style?.setProperty('width', `${indicator_line_w}px`)
this.indicatorNode?.style?.setProperty('transform', `translateX(${x}px)`)
// #endif
// 滚动到水平中心位置
const scroll_x = x - this.swiperWidth / 2
// app 平台后续支持 scrollTo()
// #ifndef MP-WEIXIN
this.tabScrollView!.scrollLeft = scroll_x
// #endif
// #ifdef MP-WEIXIN
this.tabScrollView!.scrollTo({
left: scroll_x
})
// #endif
}
}
}
</script>
<style>
.flex-row {
flex-direction: row;
align-self: flex-start;
}
.swiper-list {
flex: 1;
}
.swiper-tabs {
background-color: #ffffff;
}
.swiper-tabs-item {
color: #555;
font-size: 16px;
padding: 12px 25px;
white-space: nowrap;
}
.swiper-tabs-item-active {
color: #007AFF;
}
.swiper-tabs-indicator {
width: 1px;
height: 2px;
background-color: #007AFF;
}
.swiper-view {
flex: 1;
}
.swiper-item {
flex: 1;
padding: 15px;
}
</style>
