Comment utiliser Vue pour implémenter des effets d'actualisation déroulants

<template>
  <div class="pull-refresh"
       @touchstart="handleTouchStart"
       @touchmove="handleTouchMove"
       @touchend="handleTouchEnd">
    <div class="pull-refresh-content">
       <!-- 数据展示区域 -->
    </div>
    <div class="pull-refresh-indicator" v-show="showIndicator">
      <span class="arrow" :class="indicatorClass"></span>
      <span class="text">{{ indicatorText }}</span>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      startY: 0, // 记录用户手指触摸屏幕的纵坐标
      distanceY: 0, // 记录用户手指拖动的距离
      showIndicator: false, // 是否显示下拉刷新指示器
      indicatorText: '', // 指示器文本
      loading: false // 是否正在加载数据
    }
  },
  methods: {
    handleTouchStart(event) {
      this.startY = event.touches[0].clientY
    },
    handleTouchMove(event) {
      if (window.pageYOffset === 0 && this.startY < event.touches[0].clientY) {
        // 说明用户是在页面顶部进行下拉操作
        event.preventDefault()
        this.distanceY = event.touches[0].clientY - this.startY
        this.showIndicator = this.distanceY >= 60
        this.indicatorText = this.distanceY >= 60 ? '释放刷新' : '下拉刷新'
      }
    },
    handleTouchEnd() {
      if (this.showIndicator) {
        // 用户松开手指，开始刷新数据
        this.loading = true
        // 这里可以调用数据接口，获取最新的数据
        setTimeout(() => {
          // 模拟获取数据的延迟
          this.loading = false
          this.showIndicator = false
          this.indicatorText = ''
          // 数据更新完成，重新渲染页面
        }, 2000)
      }
    }
  },
  computed: {
    indicatorClass() {
      return {
        'arrow-down': !this.loading && !this.showIndicator,
        'arrow-up': !this.loading && this.showIndicator,
        'loading': this.loading
      }
    }
  }
}
</script>

<style scoped>

.pull-refresh {
  position: relative;
  width: 100%;
  height: 100%;
  overflow-y: scroll;
}

.pull-refresh-content {
  width: 100%;
  height: 100%;
}

.pull-refresh-indicator {
  position: absolute;
  top: -60px;
  left: 0;
  width: 100%;
  height: 60px;
  text-align: center;
  line-height: 60px;
}

.pull-refresh-indicator .arrow {
  display: inline-block;
  width: 14px;
  height: 16px;
  background: url(arrow.png);
  background-position: -14px 0;
  background-repeat: no-repeat;
  transform: rotate(-180deg);
  transition: transform 0.3s;
}

.pull-refresh-indicator .arrow-up {
  transform: rotate(0deg);
}

.pull-refresh-indicator .loading {
  background: url(loading.gif) center center no-repeat;
}
</style>