在 Bootstrap 中默认关闭手风琴

Question

我正在使用 Bootstrap 手风琴。我希望所有面板默认关闭，但我的面板开始展开。

这是我的代码：

<div class="panel-group" id="accordion" role="tablist" aria-multiselectable="false">
    <c:forEach items="${proposals}" var="proposal" varStatus="serial">
        <div class="panel panel-default">

            <div class="panel-heading" role="tab" id="heading${proposal.propID}"  >
                <h4 class="panel-title">
                    <span class="fa fa-paperclip" aria-hidden="true"></span>
                    <a class="accordion-toggle collapsed" 
                       data-toggle="collapse" data-parent="#accordion"
                       href="#collapse${proposal.propID}" aria-expanded="false"
                       aria-controls="collapse${proposal.propID}"> 
                           ${proposal.title} 
                    </a>
                </h4>
            </div>

            <div id="collapse${proposal.propID}" class="panel-collapse collapse in"
                 role="tabpanel" aria-labelledby="heading${proposal.propID}">
                ${proposal.interest}
            </div>

        </div>
    </c:forEach> 
</div>

我也使用了aria-expanded="false"，但它不起作用。

错在哪里？

Answer 1

这里的这条线似乎是罪魁祸首：

<div id="collapse${proposal.propID}" class="panel-collapse collapse in" ...

如果你在课堂上去掉in，它应该可以按照你的结构工作。看看这个例子，看看两个面板之间的区别：

<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.1/css/bootstrap.min.css" rel="stylesheet" />
<script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js"></script>

<div class="panel-group" id="accordion" role="tablist" aria-multiselectable="true">
  <div class="panel panel-default">
    <div class="panel-heading" role="tab" id="headingOne">
      <h4 class="panel-title">
        <a data-toggle="collapse" data-parent="#accordion" href="#collapseOne" aria-expanded="false" aria-controls="collapseOne">
          This Panel is Open By Default
        </a>
      </h4>
    </div>
    <div id="collapseOne" class="panel-collapse collapse in" role="tabpanel" aria-labelledby="headingOne">
      <div class="panel-body">
        Open
      </div>
    </div>
  </div>
  <div class="panel panel-default">
    <div class="panel-heading" role="tab" id="headingTwo">
      <h4 class="panel-title">
        <a class="collapsed" data-toggle="collapse" data-parent="#accordion" href="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
          This Panel Is Closed By Default
        </a>
      </h4>
    </div>
    <div id="collapseTwo" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingTwo">
      <div class="panel-body">
        Closed
      </div>
    </div>
  </div>
</div>

请注意，第一个面板的<a> 标记上没有class=collapsed，而<div> 标记上有in 类，并开始打开。第二个面板切换这些，并开始关闭。

编辑

无法制作 Bootply，不断收到“应用程序错误”。

Answer 2

最近正在使用 Bootstrap 4，但实际上无法弄清楚“in”类名称在哪里（在类似问题的多个答案中都提到了它）。

经过大量搜索，注意到更新的文档说：

collapse 插件利用几个类来处理繁重的工作：

.collapse 隐藏内容

.collapse.show 显示内容

.collapsing 在过渡开始时添加，并在过渡结束时删除

所以示例代码现在看起来像这样：

  <div id="accordion">
  <div class="card">
    <div class="card-header" id="headingOne">
      <h5 class="mb-0">
        <button class="btn btn-link" data-toggle="collapse" data-target="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
          Collapsible Group Item #1
        </button>
      </h5>
    </div>

    <div id="collapseOne" class="collapse show" aria-labelledby="headingOne" data-parent="#accordion">
      <div class="card-body">
        Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
      </div>
    </div>
  </div>

从中，这是重要的一点：

<div id="collapseOne" class="collapse show" aria-labelledby="headingOne" data-parent="#accordion">

删除“show”类名可确保 Bootstrap 手风琴默认保持折叠状态。

希望这会有所帮助！

Answer 3

你需要做的就是去掉body内容类中的show，它会默认关闭。

<div class="accordion" id="accordionExample">
                  <div class="accordion-item">
                    <h2 class="accordion-header" id="headingOne">
                      <button class="accordion-button collapsed bg-light" type="button" data-bs-toggle="collapse" data-bs-target="#collapseOne" aria-expanded="false" aria-controls="collapseOne">
                        <span class="fw-bold">All Permissions</span><span class="text-notch ms-2">Click to expand</span>
                      </button>
                    </h2>
                    <div id="collapseOne" class="accordion-collapse collapse" aria-labelledby="headingOne" data-bs-parent="#accordionExample">
                      <div class="accordion-body">
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
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                        <button type="button" class="btn btn-outline-primary mb-3 ms-3">Permission</button>
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                </div>