转换不会在按钮单击时触发

转换不会在按钮单击时触发

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Vue 转换不会在按钮单击时触发

本文介绍了Vue 转换不会在按钮单击时触发的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我是 Vue JS 的新手，我正在创建一个缩略图查看器，我将在其中获取图像和视频列表作为对象数组.首先，我将只显示 5 个项目，当用户单击顶部/底部按钮时，我想垂直滑动缩略图.

我通过引用 StackOverflow 上的一些链接创建了一个 codepen.

我正在使用 Vue Transitions 并且我的数据似乎是反应性的，但不知何故，当我单击顶部"和底部"按钮时，我看不到平滑的过渡(滑动到顶部/底部 100 像素).

HTML 代码:

<div class="row row-eq-height"><div class="thumbnail-container"><button class="up" @click="moveTop" :disabled="currentTopIndex === 0">Top</button><div :class="'slider' + (isSlidingToPrevious ? 'sliding-to-previous' : '')"><transition-group name='list' tag="ul"><li v-for="(item,index) in currentCarouselData" v-bind:key="index" class="list-item"><img :src="item.itemImage" :alt="item.itemImageAlt"/></li></transition-group>
<button @click="moveBottom" class="down" :disabled="currentBottomIndex === totalCount">Down</button>

<预>totalCount {{totalCount}}currentTopIndex {{currentTopIndex}}currentBottomIndex {{currentBottomIndex}}itemsToDisplay {{itemsToDisplay}}currentCarouselData {{currentCarouselData}}

CSS/LESS 代码:

.row-eq-height {显示:弹性；ul{列表样式类型:无；显示:弹性；弹性方向:列；溢出:隐藏；高度:自动；边框:1px纯黑色；}李{弹性:1；宽度:64px；高度:64px；位置:相对；边距:8px 0；边框:1px纯红色；图片{最大宽度:100%；最大高度:100%；}}}.list-离开-活动，.list-enter-active {过渡:0.5s；}.list-输入 {变换:翻译(0, 100px)；}.list-离开到{变换:翻译(0，-100px)；}.滑动到上一个{.list-输入 {变换:翻译(0，-100px)；}.list-离开到{变换:翻译(0, 100px)；}}

Javascript/VUE 代码:

new Vue({el: "#app",数据() {返回 {总轮播数据:[{itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test1"},{itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test2"},{itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test3"},{itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test4"},{itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test5"},{itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test6"},{itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test7"}],当前轮播数据:[]，isSlidingToPrevious: 假，总数:0，当前最高指数:0，当前底部索引:0，itemsToDisplay: 5};},计算:{}，安装(){//起初只显示5个项目this.currentCarouselData = this.totalCarouselData.slice(this.currentTopIndex,this.itemsToDisplay);//获取总计数this.totalCount = this.totalCarouselData.length;//更新当前底部索引this.currentBottomIndex = this.itemsToDisplay;},方法: {移动顶部(){this.isSlidingToPrevious = 真；this.currentTopIndex += 1;this.currentBottomIndex -= 1;this.addToTopComputedArr(this.currentBottomIndex);},移动底部(){this.isSlidingToPrevious = 假；this.currentTopIndex -= 1;this.currentBottomIndex += 1;this.addToBottomComputedArr(this.currentBottomIndex);},addToBottomComputedArr(index) {//拼接第一项this.currentCarouselData.splice(0, 1);//将下一项添加到数组中this.currentCarouselData.push(this.totalCarouselData[index - 1]);},addToTopComputedArr(index) {//拼接最后一项this.currentCarouselData.splice(index - 1, 1);//将item添加到数组的开头this.currentCarouselData.unshift(this.totalCarouselData[index - this.itemsToDisplay]);}}});
解决方案

您遇到的没有过渡问题是由 :key="index" 引起的.

检查 Vue 指南:v-for 的关键，

当 Vue 更新用 v-for 呈现的元素列表时，通过默认情况下，它使用就地补丁"策略.

这种默认模式是有效的，但仅适用于您的列表渲染输出不依赖于子组件状态或临时 DOM状态(例如表单输入值).

给 Vue 一个提示，以便它可以跟踪每个节点的身份，从而重用和重新排序现有元素，您需要提供唯一键每个项目的属性.

在您的代码中，您的五张图像始终具有相同的键=[1, 2, 3, 4, 5]，因此 Vue 将就地修补它们, 导致转换未触发.

所以只需将 :key="index" 修改为 :key="item.itemImageAlt" 即可.

最后自己调整css，使过渡效果符合你的要求.

下面是一个工作演示:

Vue.config.productionTip = false新的 Vue({el: "#app",数据() {返回 {总轮播数据:[{项目图片:"https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test1"},{项目图片:"https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test2"},{项目图片:"https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test3"},{项目图片:"https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test4"},{项目图片:"https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test5"},{项目图片:"https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test6"},{项目图片:"https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",itemImageAlt: "Test7"}],当前轮播数据:[]，isSlidingToPrevious: 假，总数:0，当前最高指数:0，当前底部索引:0，itemsToDisplay: 5};},计算:{computerCarouseData: function () {//添加计算属性返回 this.totalCarouselData.slice(-this.currentTopIndex，this.itemsToDisplay-this.currentTopIndex)}},安装(){//起初只显示5个项目this.currentCarouselData = this.totalCarouselData.slice(this.currentTopIndex,this.itemsToDisplay);//获取总计数this.totalCount = this.totalCarouselData.length;//更新当前底部索引this.currentBottomIndex = this.itemsToDisplay;},方法: {移动顶部(){this.isSlidingToPrevious = 真；this.currentTopIndex += 1;this.currentBottomIndex -= 1;this.addToTopComputedArr(this.currentBottomIndex);},移动底部(){this.isSlidingToPrevious = 假；this.currentTopIndex -= 1;this.currentBottomIndex += 1;this.addToBottomComputedArr(this.currentBottomIndex);},addToBottomComputedArr(index) {//拼接第一项this.currentCarouselData.splice(0, 1);//将下一项添加到数组中this.currentCarouselData.push(this.totalCarouselData[index - 1]);},addToTopComputedArr(index) {//拼接最后一项this.currentCarouselData.splice(index - 1, 1);//将item添加到数组的开头this.currentCarouselData.unshift(this.totalCarouselData[index - this.itemsToDisplay]);}}});
.row-eq-height {显示:弹性；}.row-eq-height ul {列表样式类型:无；显示:弹性；弹性方向:列；溢出:隐藏；高度:自动；边框:1px纯黑色；}.row-eq-height li {弹性:1；宽度:64px；高度:64px；位置:相对；边距:8px 0；边框:1px纯红色；}.row-eq-height li img {最大宽度:100%；最大高度:100%；}.list-离开-活动，.list-enter-active {过渡:全2s缓和；}.list-输入 {不透明度:0；变换:translateX(-300px);}.list-离开到{不透明度:0；变换:translateX(-300px);}.sliding-to-previous .list-enter {变换:translateY(-100px);}.sliding-to-previous .list-leave-to {变换:translateY(100px);}.list-移动{转换:转换1s；}
<script src="https://unpkg.com/[email protected]/dist/vue.js"><;/脚本><div id="app" class="container-fluid"><div class="row row-eq-height"><div class="thumbnail-container"><button class="up" @click="moveTop" :disabled="currentTopIndex === 0">Top</button><button @click="moveBottom" class="down" :disabled="currentBottomIndex === totalCount">Down</button><div :class="'slider' + (isSlidingToPrevious ? 'sliding-to-previous' : '')"><transition-group name='list' tag="ul"><li v-for="(item,index) in calculateCarouseData" v-bind:key="item.itemImageAlt" class="list-item"><img :src="item.itemImage" :alt="item.itemImageAlt" style=""/>{{item.itemImageAlt}}</li></transition-group>

<预>totalCount {{totalCount}}currentTopIndex {{currentTopIndex}}currentBottomIndex {{currentBottomIndex}}itemsToDisplay {{itemsToDisplay}}currentCarouselData {{computedCarouselData}}

I am new to Vue JS and I am creating a thumbnail viewer wherein I'll be getting a list of images and videos as an array of objects. At first, I will be showing just 5 items and when the user clicks Top / Bottom button, I want to slide the thumbnails vertically.

I have created a codepen by referring some links on StackOverflow.

I am using Vue Transitions and my data seems to be reactive but somehow I can't see the smooth transition (sliding to the top / bottom by 100px) when I click on the Top and Bottom buttons.

HTML Code: 

<div id="app" class="container-fluid">
    <div class="row row-eq-height">
        <div class="thumbnail-container">
            <button class="up" @click="moveTop" :disabled="currentTopIndex === 0">Top</button>
            <div :class="'slider' + (isSlidingToPrevious ? ' sliding-to-previous' : '')">
                <transition-group name='list' tag="ul">
                    <li v-for="(item,index) in currentCarouselData" v-bind:key="index" class="list-item"><img :src="item.itemImage" :alt="item.itemImageAlt" /></li>
                </transition-group>
            </div>
            <button @click="moveBottom" class="down" :disabled="currentBottomIndex === totalCount">Down</button>
        </div>
    </div>
    <pre>
    totalCount {{totalCount}}
    currentTopIndex {{currentTopIndex}}
    currentBottomIndex {{currentBottomIndex}}
    itemsToDisplay {{itemsToDisplay}}
    currentCarouselData {{currentCarouselData}}
</pre>
</div>

CSS / LESS Code:

.row-eq-height {
  display: flex;
  ul {
    list-style-type: none;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    height: auto;
    border: 1px solid black;
  }
  li {
    flex: 1;
    width: 64px;
    height: 64px;
    position: relative;
    margin: 8px 0;
    border: 1px solid red;
    img {
      max-width: 100%;
      max-height: 100%;
    }
  }
}

.list-leave-active,
.list-enter-active {
  transition: 0.5s;
}
.list-enter {
  transform: translate(0, 100px);
}
.list-leave-to {
  transform: translate(0, -100px);
}
.sliding-to-previous {
  .list-enter {
    transform: translate(0, -100px);
  }
  .list-leave-to {
    transform: translate(0, 100px);
  }
}

Javascript / VUE Code:

new Vue({
    el: "#app",
    data() {
        return {
            totalCarouselData: [{
                    itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
                    itemImageAlt: "Test1"
                },
                {
                    itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
                    itemImageAlt: "Test2"
                },
                {
                    itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
                    itemImageAlt: "Test3"
                },
                {
                    itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
                    itemImageAlt: "Test4"
                },
                {
                    itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
                    itemImageAlt: "Test5"
                },
                {
                    itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
                    itemImageAlt: "Test6"
                },
                {
                    itemImage: "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
                    itemImageAlt: "Test7"
                }
            ],
            currentCarouselData: [],
            isSlidingToPrevious: false,
            totalCount: 0,
            currentTopIndex: 0,
            currentBottomIndex: 0,
            itemsToDisplay: 5
        };
    },
    computed: {},
    mounted() {
        //At first show only 5 items
        this.currentCarouselData = this.totalCarouselData.slice(
            this.currentTopIndex,
            this.itemsToDisplay
        );
        //Get Total Count
        this.totalCount = this.totalCarouselData.length;
        //Update current bottom index
        this.currentBottomIndex = this.itemsToDisplay;
    },
    methods: {
        moveTop() {
            this.isSlidingToPrevious = true;
            this.currentTopIndex += 1;
            this.currentBottomIndex -= 1;
            this.addToTopComputedArr(this.currentBottomIndex);
        },
        moveBottom() {
            this.isSlidingToPrevious = false;
            this.currentTopIndex -= 1;
            this.currentBottomIndex += 1;
            this.addToBottomComputedArr(this.currentBottomIndex);
        },
        addToBottomComputedArr(index) {
            //Splice the first item
            this.currentCarouselData.splice(0, 1);
            //Add the next item to the array
            this.currentCarouselData.push(this.totalCarouselData[index - 1]);
        },
        addToTopComputedArr(index) {
            //Splice the last item
            this.currentCarouselData.splice(index - 1, 1);
            //Add item to the beginning of the array
            this.currentCarouselData.unshift(
                this.totalCarouselData[index - this.itemsToDisplay]
            );
        }
    }
});
解决方案

No transition issue you met is caused by :key="index".

Check Vue Guide: key of v-for,

In your codes, your five images always have the same key=[1, 2, 3, 4, 5], so Vue will in-place patch them, it causes the transition is not triggered.

So simply modify the :key="index" to :key="item.itemImageAlt", then it works.

Finally, adjust the css by yourself to make the transition effetcs meet your requirements.

Below is one working demo:

Vue.config.productionTip = false
new Vue({
  el: "#app",
  data() {
    return {
      totalCarouselData: [
        {
          itemImage:
            "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
          itemImageAlt: "Test1"
        },
        {
          itemImage:
            "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
          itemImageAlt: "Test2"
        },
        {
          itemImage:
            "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
          itemImageAlt: "Test3"
        },
        {
          itemImage:
            "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
          itemImageAlt: "Test4"
        },
        {
          itemImage:
            "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
          itemImageAlt: "Test5"
        },
        {
          itemImage:
            "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
          itemImageAlt: "Test6"
        },
        {
          itemImage:
            "https://www.publicdomainpictures.net/pictures/150000/velka/banner-header-tapete-145002399028x.jpg",
          itemImageAlt: "Test7"
        }
      ],
      currentCarouselData: [],
      isSlidingToPrevious: false,
      totalCount: 0,
      currentTopIndex: 0,
      currentBottomIndex: 0,
      itemsToDisplay: 5
    };
  },
  computed: {
    computedCarouseData: function () { // added computed property
        return this.totalCarouselData.slice(
        -this.currentTopIndex,
        this.itemsToDisplay-this.currentTopIndex
      )
    }
  },
  mounted() {
    //At first show only 5 items
    this.currentCarouselData = this.totalCarouselData.slice(
      this.currentTopIndex,
      this.itemsToDisplay
    );
    //Get Total Count
    this.totalCount = this.totalCarouselData.length;
    //Update current bottom index
    this.currentBottomIndex = this.itemsToDisplay;
  },
  methods: {
    moveTop() {
      this.isSlidingToPrevious = true;
      this.currentTopIndex += 1;
      this.currentBottomIndex -= 1;
      this.addToTopComputedArr(this.currentBottomIndex);
    },
    moveBottom() {
      this.isSlidingToPrevious = false;
      this.currentTopIndex -= 1;
      this.currentBottomIndex += 1;
      this.addToBottomComputedArr(this.currentBottomIndex);
    },
    addToBottomComputedArr(index) {
      //Splice the first item
      this.currentCarouselData.splice(0, 1);
      //Add the next item to the array
      this.currentCarouselData.push(this.totalCarouselData[index - 1]);
    },
    addToTopComputedArr(index) {
      //Splice the last item
      this.currentCarouselData.splice(index - 1, 1);
      //Add item to the beginning of the array
      this.currentCarouselData.unshift(
        this.totalCarouselData[index - this.itemsToDisplay]
      );
    }
  }
});
.row-eq-height {
  display: flex;
}
.row-eq-height ul {
  list-style-type: none;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  height: auto;
  border: 1px solid black;
}
.row-eq-height li {
  flex: 1;
  width: 64px;
  height: 64px;
  position: relative;
  margin: 8px 0;
  border: 1px solid red;
}
.row-eq-height li img {
  max-width: 100%;
  max-height: 100%;
}
.list-leave-active,
.list-enter-active {
  transition: all 2s ease;
}
.list-enter {
  opacity: 0;
  transform: translateX(-300px);
}
.list-leave-to {
  opacity: 0;
  transform: translateX(-300px);
}
.sliding-to-previous .list-enter {
  transform: translateY(-100px);
}
.sliding-to-previous .list-leave-to {
  transform: translateY(100px);
}
.list-move {
  transition: transform 1s;
}
<script src="https://unpkg.com/[email protected]/dist/vue.js"></script>
<div id="app" class="container-fluid">
  <div class="row row-eq-height">
    <div class="thumbnail-container">
      <button class="up" @click="moveTop" :disabled="currentTopIndex === 0">Top</button>
      <button @click="moveBottom" class="down" :disabled="currentBottomIndex === totalCount">Down</button>
      <div :class="'slider' + (isSlidingToPrevious ? ' sliding-to-previous' : '')">
        <transition-group name='list' tag="ul">
          <li v-for="(item,index) in computedCarouseData" v-bind:key="item.itemImageAlt" class="list-item"><img :src="item.itemImage" :alt="item.itemImageAlt" style=""/>{{item.itemImageAlt}}</li>
        </transition-group>
      </div>
    </div>
  </div>
  <pre>
    totalCount {{totalCount}}
    currentTopIndex {{currentTopIndex}}
    currentBottomIndex {{currentBottomIndex}}
    itemsToDisplay {{itemsToDisplay}}
    currentCarouselData {{computedCarouseData}}
</pre>
</div>

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09-06 02:26
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