Here is some code for bootstrap nav menus for wordpress. This is for anyone following along in the Bootstrap to WordPress Theme Creation Integration tutorial.

 

<nav class="navbar navbar-default">
<div class="container-fluid">
<?php wp_nav_menu( array(
'container' => 'ul',
'menu_class' => 'nav navbar-nav',
'menu_id' => 'bootmenu',
'echo' => true,
'theme_location' => 'main-menu',
) );?>
</div>
</nav>

Here is the code to collapse on mobile

<nav class="navbar navbar-default">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#myNavbar">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div class="collapse navbar-collapse" id="myNavbar">
<?php wp_nav_menu( array(
'container' => 'ul',
'menu_class' => 'nav navbar-nav',
'menu_id' => 'bootmenu',
'echo' => true,
'theme_location' => 'main-menu',
) );?>
</div>
</div>
</nav>

CSS for Sub Menus

.sub-menu{
list-style:none !important;
position:absolute;
display:none;
}
.nav li:hover > ul.sub-menu{
display: block;
margin: 0;
}

.sub-menu li{
width:100px;
margin-left:-33px;
background-color: #f8f8f8;
border-color: #e7e7e7;
padding:8px;
}

CSS For Sub Menus on Mobile

@media screen and (max-width: 760px) {
.sub-menu{
display:block !important;
position:relative;
}

.sub-menu a{
color:#666;
text-decoration:none;
cursor: pointer;
}

}

Bootstrap Function for Search

Place this in your functions.php file.

function wpdocs_my_search_form( $form ) {
$form = '<form role="search" class="navbar-form navbar-left" method="get" id="searchform" class="searchform" action="' . home_url( '/' ) . '" >
<div class="form-group">
<input type="text" class="form-control" value="' . get_search_query() . '" name="s" id="s" required/>
</div>
<button type="submit" id="searchsubmit" class="btn btn-default">Search</button>
</form>';

return $form;
}
add_filter( 'get_search_form', 'wpdocs_my_search_form' );

Add Search box to your Menu Replce Nav Code with This

<nav class="navbar navbar-default navbar-fixed-top">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#myNavbar">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div class="collapse navbar-collapse" id="myNavbar">
<?php wp_nav_menu( array(
'container' => 'ul',
'menu_class' => 'nav navbar-nav',
'menu_id' => 'bootmenu',
'echo' => true,
'theme_location' => 'main-menu',
) );?>
<?php get_search_form(); ?>
</div>
</div>
</div>
</nav>

<nav class="navbar navbar-default">
  <div class="container-fluid">
    <!-- Brand and toggle get grouped for better mobile display -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">Brand</a>
    </div>

    <!-- Collect the nav links, forms, and other content for toggling -->
    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
      <ul class="nav navbar-nav">
        <li class="active"><a href="#">Link <span class="sr-only">(current)</span></a></li>
        <li><a href="#">Link</a></li>
        <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Dropdown <span class="caret"></span></a>
          <ul class="dropdown-menu">
            <li><a href="#">Action</a></li>
            <li><a href="#">Another action</a></li>
            <li><a href="#">Something else here</a></li>
            <li role="separator" class="divider"></li>
            <li><a href="#">Separated link</a></li>
            <li role="separator" class="divider"></li>
            <li><a href="#">One more separated link</a></li>
          </ul>
        </li>
      </ul>
      <form class="navbar-form navbar-left">
        <div class="form-group">
          <input type="text" class="form-control" placeholder="Search">
        </div>
        <button type="submit" class="btn btn-default">Submit</button>
      </form>
      <ul class="nav navbar-nav navbar-right">
        <li><a href="#">Link</a></li>
        <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Dropdown <span class="caret"></span></a>
          <ul class="dropdown-menu">
            <li><a href="#">Action</a></li>
            <li><a href="#">Another action</a></li>
            <li><a href="#">Something else here</a></li>
            <li role="separator" class="divider"></li>
            <li><a href="#">Separated link</a></li>
          </ul>
        </li>
      </ul>
    </div><!-- /.navbar-collapse -->
  </div><!-- /.container-fluid -->
</nav>