在第一行文本的末尾切换箭头

Question

如何在第一行文字的末尾添加箭头？而且我希望它在崩溃时指向下方并在扩展时指向它。如下图所示。感谢您的帮助，谢谢！

Error on import matplotlib.pyplot (on Anaconda3 for Windows 10 Home 64-bit PC)

.expander {
    height: 1em;
    overflow: hidden;
    cursor: pointer;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="expander">
    Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32.
</div>

 class MyFragment: Fragment() {
 //do something
 }

代码来自

Answer 1

您可以使用<details>.标记。标签指定用户可以按需查看或隐藏的其他详细信息。

details summary::-webkit-details-marker {
  background: #fff;
  color: green;
  font-size: 200%;
  float: right;
 
}

<details>
  <summary> Contrary to popular belief , Lorem Ipsum is not..</summary>
  
  <p>Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old.  </p>
</details>

Answer 2

您可以使用伪元素创建箭头并根据类expander

进行更改

请参阅代码段：

$(".expander").click(function() {
  if ($(this).hasClass("expander")) {
    $(this).removeClass("expander");
  } else {
    $(this).addClass("expander");
  }
});

div {
  padding: 0 10px;
}

.expander {
  height: 1em;
  overflow: hidden;
  cursor: pointer;
}

div::after {
  content: '';
  width: 0;
  height: 0;
  border: 8px solid;
  border-color: #000 transparent transparent transparent;
  position: absolute;
  right: 0px;
  top: 15px;
}

.expander::after {
  top: 10px;
  border-color: transparent transparent transparent #000;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="expander">
  Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up
  one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum
  et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section
  1.10.32.
</div>

Answer 3

一种方法：

$(".expander").click(function() {
  if ($(this).hasClass("expander")) {
    $(this).removeClass("expander");
    $(".panel").addClass("open");
  } else {
    $(this).addClass("expander");
    $(".panel").removeClass("open");
  }
});

.panel {
  position: relative;
}

.expander {
  height: 1em;
  overflow: hidden;
  cursor: pointer;
  position: relative;
  padding-right: 50px;
}

.panel:after {
  content: "V";
  position: absolute;
  top: 0;
  right: 0;
  font-family: sans-serif;
}

.panel.open:after {
  transform: rotate(180deg);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="panel">
  <div class="expander">
    Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up
    one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum
    et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section
    1.10.32.
  </div>
</div>