uni-app(vue3)动态获取swiper的区域高度以及通过scroll-view实现区域滚动和scroll-view的置顶功能

计算方式:

swiper高度 = page高度 - tabs高度 - search高度

具体实现:

      <swiper class="swiper-box" :duration="500" @change="changeSwiper" 
              :current="currentSwiperIndex" :style="'height:' + swiperHeight + 'px'">
        <swiper-item class="swiper-item">
          <scroll-view scroll-y="true" :show-scrollbar="false" 
                      :style="'height:' + swiperHeight + 'px'" 
                      @scrolltolower="lower" :scroll-top="scrollTop" @scroll="scroll">
            <Recommend :openUpdateFlag="openUpdateFlag" @closeUpdateFlag="handleDataUpdate" />
          </scroll-view>
        </swiper-item>
      </swiper>
    </view>
    <!-- 置顶 -->
    <view class="topIcon" v-if="isShowArrowUpward" @click="goScrollTop">
      <up-icon name="arrow-upward" color="#fff" size="28"></up-icon>
    </view>

• swiperHeight：计算swiper动态高度
• :scroll-top: 用于重置"scroll"高度
• @scroll: 获取"scroll"滚动后的信息
• @scrolltolower: 触底后自动触发,用于异步请求以加载更多数据
• :show-scrollbar: 不显示滚动条

注意: scroll-view同样需要计算区域高度

const isShowArrowUpward = ref(false); // 置顶图标
const swiperHeight = ref(0); // swiper高度
const tmpScrollHeight = ref(0); // 记录scroll临时高度
const scrollTop = ref(0); // 重置scroll高度

计算swiper的高度

// 计算swiper的高度
onMounted(() => {
  let headerSearchHeight,
    headerTabsHeight = 0;
  // 头部搜索height: header-container
  let headerSearchView = uni.createSelectorQuery().select('.header-container');
  headerSearchView
    .boundingClientRect((data) => {
      headerSearchHeight = data.height;
    })
    .exec();
  // 顶部tabs-height:
  let headerTabsView = uni.createSelectorQuery().select('.u-tabs');
  headerTabsView
    .boundingClientRect((data) => {
      headerTabsHeight = data.height;
    })
    .exec();
  // swiper-height
  uni.getSystemInfo({
    success: (res) => {
      swiperHeight.value = res.windowHeight - headerSearchHeight - headerTabsHeight;
    }
  });
});

注意: 需要在dom渲染完成后(onMounted、onReady)才能获取到高度值

/**
 * scroll-view 是区域滚动,所以无法去监听屏幕滚动
 */
const scroll = (e) => {
  // 记录"scroll-view"临时滚动的高度
  tmpScrollHeight.value = e.detail.scrollTop;
  if (e.detail.scrollTop > 400) {
    // 显示"置顶"图标 
    isShowArrowUpward.value = true;
  } else {
    isShowArrowUpward.value = false;
  }
};

scroll-view置顶(方案一： 无动画)

// scroll-view高度置顶
const goScrollTop = () => {
  // 解决view层不同步的问题
  scrollTop.value = tmpScrollHeight.value;
  // 强制刷新
  nextTick(() => {
    scrollTop.value = 0;
  });
};

scroll-view置顶(方案二: 添加过渡动画)

JavaScript 模拟平滑滚动（适用于所有平台,包括微信小程序）‌

const scrollDuration = 300; // 动画时长（ms）

const goScrollTop = () => {
  // 解决view层不同步的问题
  scrollTop.value = tmpScrollHeight.value;
  const startTime = Date.now();
  const startTop = scrollTop.value;
  const distance = startTop; // 需要滚动的距离

  const scrollStep = () => {
    const currentTime = Date.now();
    const timeElapsed = currentTime - startTime;
    const progress = Math.min(timeElapsed / scrollDuration, 1); // 0~1

    // 使用缓动函数（如 easeOutQuad）
    const easeProgress = 1 - Math.pow(1 - progress, 2);
    scrollTop.value = startTop - distance * easeProgress;

    if (timeElapsed < scrollDuration) {
      requestAnimationFrame(scrollStep);
    } else {
      // 强制刷新
      nextTick(() => {
        scrollTop.value = 0; // 确保最终位置准确
      });
    }
  };
  requestAnimationFrame(scrollStep);
};

.topIcon {
  position: fixed;
  bottom: 120rpx;
  right: 30rpx;
  width: 44rpx;
  height: 44rpx;
  background-color: rgb(0, 0, 0, 0.5);
  border-radius: 40rpx;
  display: flex;
  justify-content: center;
  align-items: center;
}