jquery - toggleClass() 对我不起作用

Question

我正在尝试设置一个视频库，当我将鼠标悬停在视频缩略图上时，我希望播放按钮从不透明度:.3 更改为不透明度:1。我试图通过使用带有toggleClass() 的jQuery 脚本来实现此目的。我尝试过使用具有不透明度的 animate() ，效果很好。但我想使用toggleClass() 方法。但是当我悬停时什么也没有发生。

//Fade in Play Button
$('.gallery-poster-play-button').hover(function() {
  $('.gallery-poster-play-button img').toggleClass('toggle-opacity-play-button');
});

.video-list {
  display: flex;
  justify-content: flex-start;
  list-style: none;
}

.video-list li {
  margin-right: 10px;
  transition: all .3s;
}

.video-list li:hover {
  transform: scale(0.98);
  cursor: pointer;
}

.video-list li img {
  border-radius: 4px;
}

.video-list li a {
  display: block;
  padding: 5px;
  text-decoration: none;
}

.play-button {
  position: relative;
}

.gallery-poster-play-button {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
}

.gallery-poster-play-button img {
  position: absolute;
  left: 40%;
  top: 35%;
  vertical-align: middle;
  opacity: .3;
}

.toggle-opacity-play-button {
  opacity: 1;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul id="video-gallery" class="video-list">
  <li class="play-button" data-poster="../assets/videos/posters/video-poster-1.png" data-sub-html="video caption1" data-html="#video1">
    <img src="../assets/videos/posters/video-poster-11.png" />
    <div class="gallery-poster-play-button">
      <img src="../assets/data/node_modules/lightgallery/dist/img/video-play.png" alt="">
    </div>
  </li>
  <li class="play-button" data-poster="../assets/videos/posters/video-poster-2.png" data-sub-html="video caption2" data-html="#video2">
    <img src="../assets/videos/posters/video-poster-22.png" />
    <div class="gallery-poster-play-button">
      <img src="../assets/data/node_modules/lightgallery/dist/img/video-play.png" alt="">
    </div>
  </li>
</ul>

Answer 1

问题是因为 .toggle-opacity-play-button 规则不够具体，无法覆盖 .gallery-poster-play 中的 opacity 设置-按钮img。您需要增加特异性。您还需要使用 $(this).find('img') 仅影响当前元素的子元素，如下所示:

.gallery-poster-play-button img.toggle-opacity-play-button {
  opacity: 1;
}

//Fade in Play Button
$('.gallery-poster-play-button').hover(function() {
  $(this).find('img').toggleClass('toggle-opacity-play-button');
});

.video-list {
  display: flex;
  justify-content: flex-start;
  list-style: none;
}

.video-list li {
  margin-right: 10px;
  transition: all .3s;
}

.video-list li:hover {
  transform: scale(0.98);
  cursor: pointer;
}

.video-list li img {
  border-radius: 4px;
}

.video-list li a {
  display: block;
  padding: 5px;
  text-decoration: none;
}

.play-button {
  position: relative;
}

.gallery-poster-play-button {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
}

.gallery-poster-play-button img {
  position: absolute;
  left: 40%;
  top: 35%;
  vertical-align: middle;
  opacity: .3;
}

.gallery-poster-play-button img.toggle-opacity-play-button {
  opacity: 1;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul id="video-gallery" class="video-list">
  <li class="play-button" data-poster="../assets/videos/posters/video-poster-1.png" data-sub-html="video caption1" data-html="#video1">
    <img src="../assets/videos/posters/video-poster-11.png" />
    <div class="gallery-poster-play-button">
      <img src="../assets/data/node_modules/lightgallery/dist/img/video-play.png" alt="">
    </div>
  </li>
  <li class="play-button" data-poster="../assets/videos/posters/video-poster-2.png" data-sub-html="video caption2" data-html="#video2">
    <img src="../assets/videos/posters/video-poster-22.png" />
    <div class="gallery-poster-play-button">
      <img src="../assets/data/node_modules/lightgallery/dist/img/video-play.png" alt="">
    </div>
  </li>
</ul>

话虽如此，您根本不需要使用 JS，因为 CSS :hover 伪选择器在这里可以正常工作:

.video-list {
  display: flex;
  justify-content: flex-start;
  list-style: none;
}

.video-list li {
  margin-right: 10px;
  transition: all .3s;
}

.video-list li:hover {
  transform: scale(0.98);
  cursor: pointer;
}

.video-list li img {
  border-radius: 4px;
}

.video-list li a {
  display: block;
  padding: 5px;
  text-decoration: none;
}

.play-button {
  position: relative;
}

.gallery-poster-play-button {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
}

.gallery-poster-play-button img {
  position: absolute;
  left: 40%;
  top: 35%;
  vertical-align: middle;
  opacity: .3;
}

.gallery-poster-play-button:hover img {
  opacity: 1;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul id="video-gallery" class="video-list">
  <li class="play-button" data-poster="../assets/videos/posters/video-poster-1.png" data-sub-html="video caption1" data-html="#video1">
    <img src="../assets/videos/posters/video-poster-11.png" />
    <div class="gallery-poster-play-button">
      <img src="../assets/data/node_modules/lightgallery/dist/img/video-play.png" alt="">
    </div>
  </li>
  <li class="play-button" data-poster="../assets/videos/posters/video-poster-2.png" data-sub-html="video caption2" data-html="#video2">
    <img src="../assets/videos/posters/video-poster-22.png" />
    <div class="gallery-poster-play-button">
      <img src="../assets/data/node_modules/lightgallery/dist/img/video-play.png" alt="">
    </div>
  </li>
</ul>