How to implement pull-up loading function in vue2

This article mainly introduces the pull-up loading function based on vue2 in detail. It has certain reference value. Interested friends can refer to it.

The example in this article shares with you the implementation of vue2. The specific code for pull loading display is for your reference. The specific content is as follows

Because swiper is also used in our project. Many of them are sliding to switch, but they have to be pulled up to load. As a result, many UI frameworks we used have different bugs. We had no choice but to write one in the end. The code is as follows (this is used in many places, so it is recommended to place it under components/common):

<template>
  <p class="loadmore">
    <slot></slot>
    <slot name="bottom">
    </slot>
  </p>
</template>

<style>
  .loadmore{
    width:100%;
  }
</style>

<script>
  export default {
    name: &#39;loadmore&#39;,
    props: {
      maxDistance: {
        type: Number,
        default: 0
      },
      autoFill: {
        type: Boolean,
        default: true
      },
      distanceIndex: {
        type: Number,
        default: 2
      },
      bottomPullText: {
        type: String,
        default: &#39;上拉刷新&#39;
      },
      bottomDropText: {
        type: String,
        default: &#39;释放更新&#39;
      },
      bottomLoadingText: {
        type: String,
        default: &#39;加载中...&#39;
      },
      bottomDistance: {
        type: Number,
        default: 70
      },
      bottomMethod: {
        type: Function
      },
      bottomAllLoaded: {
        type: Boolean,
        default: false
      },
    },
    data() {
      return {
        // 最下面出现的p的位移
        translate: 0,
        // 选择滚动事件的监听对象
        scrollEventTarget: null,
        containerFilled: false,
        bottomText: &#39;&#39;,
        // class类名
        bottomDropped: false,
        // 获取监听滚动元素的scrollTop
        bottomReached: false,
        // 滑动的方向  down---向下互动；up---向上滑动
        direction: &#39;&#39;,
        startY: 0,
        startScrollTop: 0,
        // 实时的clientY位置
        currentY: 0,
        topStatus: &#39;&#39;,
        // 上拉加载的状态  &#39;&#39;   pull: 上拉中
        bottomStatus: &#39;&#39;,
      };
    },
    watch: {
      // 改变当前加载在状态
      bottomStatus(val) {
        this.$emit(&#39;bottom-status-change&#39;, val);
        switch (val) {
          case &#39;pull&#39;:
            this.bottomText = this.bottomPullText;
            break;
          case &#39;drop&#39;:
            this.bottomText = this.bottomDropText;
            break;
          case &#39;loading&#39;:
            this.bottomText = this.bottomLoadingText;
            break;
        }
      }
    },
    methods: {
      onBottomLoaded() {
        this.bottomStatus = &#39;pull&#39;;
        this.bottomDropped = false;
        this.$nextTick(() => {
          if (this.scrollEventTarget === window) {
          document.body.scrollTop += 50;
        } else {
          this.scrollEventTarget.scrollTop += 50;
        }
        this.translate = 0;
      });
        // 注释
        if (!this.bottomAllLoaded && !this.containerFilled) {
          this.fillContainer();
        }
      },

      getScrollEventTarget(element) {
        let currentNode = element;
        while (currentNode && currentNode.tagName !== &#39;HTML&#39; &&
        currentNode.tagName !== &#39;BODY&#39; && currentNode.nodeType === 1) {
          let overflowY = document.defaultView.getComputedStyle(currentNode).overflowY;
          if (overflowY === &#39;scroll&#39; || overflowY === &#39;auto&#39;) {
            return currentNode;
          }
          currentNode = currentNode.parentNode;
        }
        return window;
      },
      // 获取scrollTop
      getScrollTop(element) {
        if (element === window) {
          return Math.max(window.pageYOffset || 0, document.documentElement.scrollTop);
        } else {
          return element.scrollTop;
        }
      },
      bindTouchEvents() {
        this.$el.addEventListener(&#39;touchstart&#39;, this.handleTouchStart);
        this.$el.addEventListener(&#39;touchmove&#39;, this.handleTouchMove);
        this.$el.addEventListener(&#39;touchend&#39;, this.handleTouchEnd);
      },
      init() {
        this.bottomStatus = &#39;pull&#39;;
        // 选择滚动事件的监听对象
        this.scrollEventTarget = this.getScrollEventTarget(this.$el);
        if (typeof this.bottomMethod === &#39;function&#39;) {
          // autoFill 属性的实现  注释
          this.fillContainer();
          // 绑定滑动事件
          this.bindTouchEvents();
        }
      },
      // autoFill 属性的实现  注释
      fillContainer() {
        if (this.autoFill) {
          this.$nextTick(() => {
            if (this.scrollEventTarget === window) {
            this.containerFilled = this.$el.getBoundingClientRect().bottom >=
                document.documentElement.getBoundingClientRect().bottom;
          } else {
            this.containerFilled = this.$el.getBoundingClientRect().bottom >=
                this.scrollEventTarget.getBoundingClientRect().bottom;
          }
          if (!this.containerFilled) {
            this.bottomStatus = &#39;loading&#39;;
            this.bottomMethod();
          }
        });
        }
      },
      // 获取监听滚动元素的scrollTop
      checkBottomReached() {
        if (this.scrollEventTarget === window) {
          return document.body.scrollTop + document.documentElement.clientHeight >= document.body.scrollHeight;
        } else {
          // getBoundingClientRect用于获得页面中某个元素的左，上，右和下分别相对浏览器视窗的位置。 right是指元素右边界距窗口最左边的距离，bottom是指元素下边界距窗口最上面的距离。
          return this.$el.getBoundingClientRect().bottom <= this.scrollEventTarget.getBoundingClientRect().bottom + 1;
        }
      },
      // ontouchstart 事件
      handleTouchStart(event) {
        // 获取起点的y坐标
        this.startY = event.touches[0].clientY;
        this.startScrollTop = this.getScrollTop(this.scrollEventTarget);
        this.bottomReached = false;
        if (this.bottomStatus !== &#39;loading&#39;) {
          this.bottomStatus = &#39;pull&#39;;
          this.bottomDropped = false;
        }
      },
      // ontouchmove事件
      handleTouchMove(event) {
        if (this.startY < this.$el.getBoundingClientRect().top && this.startY > this.$el.getBoundingClientRect().bottom) {
          // 没有在需要滚动的范围内滚动，不再监听scroll
          return;
        }
        // 实时的clientY位置
        this.currentY = event.touches[0].clientY;
        // distance 移动位置和开始位置的差值    distanceIndex---
        let distance = (this.currentY - this.startY) / this.distanceIndex;
        // 根据 distance 判断滑动的方向 并赋予变量  direction down---向下互动；up---向上滑动
        this.direction = distance > 0 ? &#39;down&#39; : &#39;up&#39;;
        if (this.direction === &#39;up&#39;) {
          // 获取监听滚动元素的scrollTop
          this.bottomReached = this.bottomReached || this.checkBottomReached();
        }
        if (typeof this.bottomMethod === &#39;function&#39; && this.direction === &#39;up&#39; &&
            this.bottomReached && this.bottomStatus !== &#39;loading&#39; && !this.bottomAllLoaded) {
          // 有加载函数，是向上拉，有滚动距离，不是正在加载ajax，没有加载到最后一页
          event.preventDefault();
          event.stopPropagation();
          if (this.maxDistance > 0) {
            this.translate = Math.abs(distance) <= this.maxDistance
                ? this.getScrollTop(this.scrollEventTarget) - this.startScrollTop + distance : this.translate;
          } else {
            this.translate = this.getScrollTop(this.scrollEventTarget) - this.startScrollTop + distance;
          }
          if (this.translate > 0) {
            this.translate = 0;
          }
          this.bottomStatus = -this.translate >= this.bottomDistance ? &#39;drop&#39; : &#39;pull&#39;;
        }
      },
      // ontouchend事件
      handleTouchEnd() {
        if (this.direction === &#39;up&#39; && this.bottomReached && this.translate < 0) {
          this.bottomDropped = true;
          this.bottomReached = false;
          if (this.bottomStatus === &#39;drop&#39;) {
            this.translate = &#39;-50&#39;;
            this.bottomStatus = &#39;loading&#39;;
            this.bottomMethod();
          } else {
            this.translate = &#39;0&#39;;
            this.bottomStatus = &#39;pull&#39;;
          }
        }
        this.direction = &#39;&#39;;
      }
    },
    mounted() {
      this.init();
    }
  };
</script>

Then import it on which page it is needed: import LoadMore from './../common/ loadmore.vue';The page where you need to introduce it is written as follows:

<template>
 <section class="finan">
  <!-- 上拉加载更多 -->
  <load-more
  :bottom-method="loadBottom"
  :bottom-all-loaded="allLoaded"
  :bottomPullText=&#39;bottomText&#39;
  :auto-fill="false"
  @bottom-status-change="handleBottomChange"
  ref="loadmore">
    <p>
  这里写你需要的另外的模块
    </p>
    <p v-show="loading" slot="bottom" class="loading"> 这个p是为让上拉加载的时候显示一张加载的gif图
     <img src="./../../assets/main/uploading.gif">
    </p>
  </load-more>
 </section>
</template>

Then set the data and methods in this page as follows:

  export default {
    name: 'FinancialGroup',
    props:{
 
    },
    data () {
      return {
        // 上拉加载数据
        scrollHeight: 0,
        scrollTop: 0,
        containerHeight: 0,
        loading: false,
        allLoaded: false,
        bottomText: '上拉加载更多...',
        bottomStatus: '',
        pageNo: 1,
        totalCount: '',
      }
    },
    methods: {
    /* 下拉加载 */
    _scroll: function(ev) {
      ev = ev || event;
      this.scrollHeight = this.$refs.innerScroll.scrollHeight;
      this.scrollTop = this.$refs.innerScroll.scrollTop;
      this.containerHeight = this.$refs.innerScroll.offsetHeight;
    },
    loadBottom: function() {
      this.loading = true;
      this.pageNo += 1;  // 每次更迭加载的页数
      if (this.pageNo == this.totalGetCount) {
        // 当allLoaded = true时上拉加载停止
        this.loading = false;
        this.allLoaded = true;
      }
      api.commonApi(后台接口，请求参数) 这个api是封装的axios有不懂的可以看vue2+vuex+axios那篇文章
          .then(res => {
        setTimeout(() => {
      要使用的后台返回的数据写在setTimeout里面
         this.$nextTick(() => {
          this.loading = false;
        })
      }, 1000)
     });
    },
    handleBottomChange(status) {
      this.bottomStatus = status;
    },
  }

The above is what I compiled for everyone. I hope that in the future It will be helpful to everyone.

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