Question

我有一个非常简单的引导问题，我想解决。

根据指南（https://getbootstrap.com/docs/4.0/components/dropdowns/），.dropdown-menu类和下拉菜单切换必须包含在.dropdown或其他声明position: relative;的元素中。

但是到目前为止，如果我将.dropdown-menu置于与我的切换相同的级别，我只能让它工作。因此，我只能在右下角得到一个小的下拉列表。

但是，如果我将整个.dropdown-menu div块向下移动两个级别（在.input-group .dropdown div块内），我会实现这样的效果......

...这正是我想要的，但是，在控制台上，bootstrap / popper会发出一个错误告诉我Cannot read property 'setAttribute' of undefined，而下拉菜单不再缩回了，那就是我的地方我被卡住了。

我在底部包含了一个工作代码示例（第一张图片）供您试用，请告诉我是否使用了下拉类错误了？

非常感谢先进的

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
<div class="container">
  <div class="row">
    <div class="col-12">
      <div class="input-group dropdown">
        <input type="text" class="form-control" id="project_search" placeholder="search ...">
        <div class="input-group-append">
          <div class="btn-group">
            <button class="btn bg-primary text-white" type="button">Search</button>
            <button class="btn bg-primary text-white dropdown-toggle dropdown-toggle-split" id="searchAdvancedFilter" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
              <span class="caret"></span>
              <span class="sr-only">Toggle Dropdown</span>
            </button>
            <div class="dropdown-menu dropdown-menu-right w-100" aria-labelledby="searchAdvancedFilter">
              <h6 class="dropdown-header">Advanced Settings</h6>
              <div class="dropdown-divider"></div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

编辑：我找到了解决问题的方法，但后来遇到了另一个问题，首先，这是代码。

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
<div class="container">
  <div class="row">
    <div class="col-12">
      <div class="input-group dropdown">
        <input type="text" class="form-control" id="project_search" placeholder="search ...">
        <button class="btn bg-primary text-white" type="button">Search</button>
        <button class="btn bg-primary text-white dropdown-toggle dropdown-toggle-split" id="searchAdvancedFilter" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          <span class="caret"></span>
          <span class="sr-only">Toggle Dropdown</span>
        </button>
        <div class="dropdown-menu dropdown-menu-right w-100" aria-labelledby="searchAdvancedFilter">
          <h6 class="dropdown-header">Advanced Settings</h6>
          <div class="dropdown-divider"></div>
        </div>
      </div>
    </div>
  </div>
</div>

我所做的是我删除了.input-group-append div和.btn-group div，并将.dropdown-menu权限置于.dropdown下，并进行了切换与菜单处于同一级别。一切正常......期待.input-group / .btn-group样式现在已经毁了。

没有手动使用CSS类来覆盖它们，我的类结构与以前的版本有什么不对，导致它无法实现我想要实现的功能吗？

Answer 1

像这样包含btn-group position:static ......

https://www.codeply.com/go/6kJ3E53PuF

<div class="container">
  <div class="row">
    <div class="col-12">
      <div class="input-group dropdown">
        <input type="text" class="form-control" id="project_search" placeholder="search ...">
        <div class="input-group-append">
          <div class="btn-group position-static">
            <button class="btn bg-primary text-white" type="button">Search</button>
            <button class="btn bg-primary text-white dropdown-toggle dropdown-toggle-split" id="searchAdvancedFilter" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
              <span class="caret"></span>
              <span class="sr-only">Toggle Dropdown</span>
            </button>
            <div class="dropdown-menu dropdown-menu-right w-100" aria-labelledby="searchAdvancedFilter">
              <h6 class="dropdown-header">Advanced Settings</h6>
              <div class="dropdown-divider"></div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

工作原理：

Bootstrap 4中的dropdown-menu为position:absolute，默认情况下，btn-group为position:relative。 position:absolute容器内的position:relative元素将相对于容器调整大小。但是，当position:absolute元素放置在position:static容器内时，将不再相对于容器调整大小。这允许dropdown-menu调整dropdown的全宽。 See this example of absolute inside relative vs. static

Bootstrap4下拉菜单填充输入组

1 个答案: