twitter-bootstrap - Bootstrap 4 中的左对齐和右对齐模态页脚按钮

Question

Bootstrap 4 使用 Flex-box 作为模式页脚。如果我想要两个按钮，一左一右，如何才能使其正常工作？

下面的代码尝试将 div.row 与 col-sm-6 一起使用，但不起作用。

<script src="https://code.jquery.com/jquery-3.1.1.slim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.4.0/js/tether.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" rel="stylesheet"/>

<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#myModal">
  Launch demo modal
</button>

<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
      <div class="row">
        <div class="col-sm-6 text-left">
        <button type="button" class="btn btn-primary">Save changes</button>
        </div>
        <div class="col-sm-6 text-right">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        </div>
      </div>
      </div>
    </div>
  </div>
</div>

Answer 1

既然 modal-footer 在 Bootstrap 4 中是“display:flex”，那么使用自动边距将是最简单的。使用左侧按钮上的 mr-auto。

<div class="modal-footer">
     <button type="button" class="btn btn-primary mr-auto">Save changes</button>
     <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
</div>

Demo

另请参阅:Left align and right align within div in Bootstrap

<小时/>

后续评论“如果我需要右侧的按钮占据所有剩余空间怎么办？” - 使用btn-block类:

<div class="modal-footer">
     <button type="button" class="btn btn-primary text-nowrap">Save changes</button>
     <button type="button" class="btn btn-secondary btn-block ml-1" data-dismiss="modal">Close</button>
</div>