css - 单击显示更多按钮时如何使用缓入

Question

I want to have an animation of ease-in/out for 3 seconds when clicking show more, but I find that I cna't achieve it since I am using overflow: hidden and -webkit-line-clamp: 2;

Is there other ways to do so?

HelloWorlfd.vue

<template>
  <div class="item">
    <div :class="{ description: true, 'description--hidden': isShowMore }">
      Lorem Ipsum is simply dummy text of the printing and typesetting industry.
      Lorem Ipsum has been the industry's standard dummy text ever since the
      1500s, when an unknown printer took a galley of type and scrambled it to
      make a type specimen book. It has survived not only five centuries, but
      also the leap into electronic typesetting, remaining essentially
      unchanged. It was popularised in the 1960s with the release of Letraset
      sheets containing Lorem Ipsum passages, and more recently with desktop
      publishing software like Aldus PageMaker including versions of Lorem
      Ipsum.
    </div>
    <button class="show-more-btn" @click="toggleShowMore">
      <span>show More</span>
    </button>
  </div>
</template>
<script>
export default {
  components: {},
  data() {
    return {
      isShowMore: false,
    };
  },
  methods: {
    toggleShowMore() {
      this.isShowMore = !this.isShowMore;
    },
  },
};
</script>
<style scoped lang="scss">
.item {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 558px;
  height: auto;
  .description {
    margin-bottom: 36px;
  }
  .description--hidden {
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2; /* number of lines to show */
    -webkit-box-orient: vertical;
  }
  .show-more-btn {
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: 600;
    background-color: transparent;
    border: none;
    &:hover {
      cursor: pointer;
    }
    span {
      padding: 0 0.5rem;
    }
  }
}
</style>

CodeSandbox:
https://codesandbox.io/s/magical-https-ukev7?file=/src/components/HelloWorld.vue:0-1726

Answer 1

As you stated, -webkit-line-clamp: 2 may be a reason the animation won't play. However, overflow: hidden should not prevent this if we use the animation property with a keyframe, to delay its timing.

In addition we can create the dropdown effect by using the transition property, and max-height.

Below is a version of your css, that will get you the transition you want :)

You can adjust the property values for height, and timings for animation and transition, as you see fit.

Let me know if this helps :) !

.description {
    margin-bottom: 36px;
    max-height: 500px;
    transition: all ease-in 0.3s;
    overflow: auto;
  }
  @keyframes delay-overflow {
    from { overflow: auto; }
  }
  .description--hidden {
    max-height: 40px;
    overflow:hidden;
    animation: 1s delay-overflow;
  }