Bootstrap 3 到 4 升级问题？

Question

我从 bootstrap 3 升级到了 4，以便可以使用新的卡片功能，但是所有格式都消失了，所以我切换回 boostrap 3，我需要在一行中显示多个图像，并在下面的描述中水平滚动。

以下是我正在寻找的格式。

这是在 4 中工作的引导代码，我需要以某种方式使其在 3 中工作。

 <div class="col-lg-4 col-md-6 mb-4">
              <div class="card h-100">
                <a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
                <div class="card-body">
                  <h4 class="card-title">
                    <a href="#">Item Three</a>
                  </h4>
                  <h5>$24.99</h5>
                  <p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur!</p>
                </div>
                <div class="card-footer">
                  <small class="text-muted">&#9733; &#9733; &#9733; &#9733; &#9734;</small>
                </div>
              </div>
            </div>

            <div class="col-lg-4 col-md-6 mb-4">
              <div class="card h-100">
                <a href="#"><img class="card-img-top" src="http://placehold.it/700x400" alt=""></a>
                <div class="card-body">
                  <h4 class="card-title">
                    <a href="#">Item Four</a>
                  </h4>
                  <h5>$24.99</h5>
                  <p class="card-text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Amet numquam aspernatur!</p>
                </div>
                <div class="card-footer">
                  <small class="text-muted">&#9733; &#9733; &#9733; &#9733; &#9734;</small>
                </div>
              </div>
            </div>

Answer 1

Bootstrap 4 几乎是 Bootstrap 3 的完全重写。

因此，几乎所有内容都发生了变化，您需要手动迁移所有组件。

这是 Bootstrap 4 中导航栏的示例（您可以看到它完全不同）：

<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>

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Link</a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
      <li class="nav-item">
        <a class="nav-link disabled" href="#">Disabled</a>
      </li>
    </ul>
    <form class="form-inline my-2 my-lg-0">
      <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav>

查看文档：

https://getbootstrap.com/docs/4.0/components/navbar/