twitter-bootstrap – 如何创建另一个bootstrap折叠导航栏按钮？

左侧折叠,右侧折叠.

更新

这就是我到目前为止所拥有的.我想按钮组项目在为较小的显示器调整大小时,采用导航栏最左侧角的bootstrap(带图标栏)的默认行为.

<nav class="navbar navbar-default navbar-fixed-top" role="navigation">
  <header class="container">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>          
    </div>
    <div class="collapse navbar-collapse">
      <ul class="nav navbar-nav navbar-right">
        <li class="dropdown">
          <div class="btn-group header-dropdown nav navbar-nav">
            <button type="button" class="btn btn-success">Select City</button>
            <button type="button" class="btn btn-success dropdown-toggle" data-toggle="dropdown">
              <span class="caret"></span>
              <span class="sr-only">Toggle Dropdown</span>
            </button>
            <ul class="dropdown-menu" role="menu">
              <li><a href="#">Chennai</a></li>
              <li><a href="#">Bangalore</a></li>
              <li><a href="#">Mumbai</a></li>
              <li class="divider"></li>
              <li><a href="#">Others</a></li>
            </ul>
          </div>
        </li>

        <li><a href="#">Item 1</a></li>
        <li><a href="#">Item 2</a></li>
        <li><a href="#">Item 3</a></li>
      </ul>
    </div>
  </header>
</nav>