How to customize Navbar property in Yii2

Question

I have navigation header like this:

<div class="navbar navbar-inverse navbar-fixed-top" role="navigation">
  <div class="container-fluid">
    <div class="navbar-collapse collapse">
      <form class="navbar-form navbar-right" role="search">
        <div class="form-group has-feedback">
            <input id="searchbox" type="text" placeholder="Search" class="form-control">
            <span id="searchicon" class="fa fa-search form-control-feedback"></span>
        </div>
      </form>
    </div><!--/.navbar-collapse -->
  </div>
</div>

I have problem when I want to convert this code using yii\bootstrap\NavBar;:

<div class="navbar-collapse collapse">
     <form class="navbar-form navbar-right" role="search">
           <div class="form-group has-feedback">
                <input id="searchbox" type="text" placeholder="Search" class="form-control">
                <span id="searchicon" class="fa fa-search form-control-feedback"></span>
            </div>
      </form>
</div><!--/.navbar-collapse -->

And this is the code of my Layout using yii\bootstrap\NavBar;:

<?php
    NavBar::begin([
        'brandLabel' => 'My Company',
        'brandUrl' => Yii::$app->homeUrl,
        'options' => [
            'class' => 'navbar navbar-inverse navbar-fixed-top',
            'role' => 'navigation',
        ],
    ]);
    NavBar::end();
?>

I have been read Navbar Widget, but still don't understand. Is there anyone who can teach me to using Navbar widget on Yii2 framework?.

Solution

Ok here is the code for that,here i am just placing the searchbox from exactly what you posted in question and i am guessing that you know how to echo other menu links in navbar

Anyway it goes like this

<?php
NavBar::begin([
'brandLabel' => 'My Company',
'brandUrl' => Yii::$app->homeUrl,
'options' => [
    'class' => 'navbar navbar-inverse navbar-fixed-top',
    'role' => 'navigation',
],
]);

$menuItems = [
    ['label' => 'Home', 'url' => ['controller url here']],
];

 echo Nav::widget([
    'options' => ['class' => 'navbar-nav navbar-right'],
    'items' => $menuItems,
]);
echo "<form class='navbar-form navbar-right' role='search'>
       <div class='form-group has-feedback'>
            <input id='searchbox' type='text' placeholder='Search' class='form-control'>
            <span id='searchicon' class='fa fa-search form-control-feedback'></span>
        </div>
  </form>";
NavBar::end();
?>