wp_nav_menu change & add sub-menu & li>a class name? - wordpress

Question

I found lots of methods to change the "sub-menu", but the problem is my friend coded a new Walker_Nav_Menu and here is the code.
All I want is:
to add a class in 3rd line where CLASS="ADD New HERE"
to change the class in 4th line, from <ul class="sub-menu"> to <ul class="dropdown">
again add a class in the 5th line, just like the 3rd line.
<ul id="menu-herid" class="nav navbar-nav" data-breakpoint="800">
<li id="menu-item-2821" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-has-children">
<a CLASS="ADD New HERE" href="http://theme.dev/home/">Home</a>
<ul class="sub-menu">
<li id="menu-item-2838" class="menu-item menu-item-type-post_type menu-item-object-page">
Blog with Slideshow
</li>
</ul>
</li>
</ul>
// Navigation with description
if (! class_exists('hs_description_walker')) {
class hs_description_walker extends Walker_Nav_Menu {
function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
global $wp_query;
$indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
$class_names = $value = 'class="dropdown"';
$classes = empty( $item->classes ) ? array() : (array) $item->classes;
$class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item ) );
$class_names = ' class="'. esc_attr( $class_names ) . '"';
$output .= $indent . '<li id="menu-item-'. $item->ID . '"' . $value . $class_names .'>';
$attributes = ! empty( $item->attr_title ) ? ' title="' . esc_attr( $item->attr_title ) .'"' : '';
$attributes .= ! empty( $item->target ) ? ' target="' . esc_attr( $item->target ) .'"' : '';
$attributes .= ! empty( $item->xfn ) ? ' rel="' . esc_attr( $item->xfn ) .'"' : '';
$attributes .= ! empty( $item->url ) ? ' href="' . esc_attr( $item->url ) .'"' : '';
$description = ! empty( $item->description ) ? '<span class="desc">'.esc_attr( $item->description ).'</span>' : '';
if($depth != 0) {
$description = $append = $prepend = "";
}
$item_output = $args->before;
$item_output .= '<a'. $attributes .'>';
$item_output .= $args->link_before;
if (isset($prepend))
$item_output .= $prepend;
$item_output .= apply_filters( 'the_title', $item->title, $item->ID );
if (isset($append))
$item_output .= $append;
$item_output .= $description.$args->link_after;
$item_output .= '</a>';
$item_output .= $args->after;
$output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
}
}
}
Now the thing is I wanted the sub-menu to be changed to ""

Answer 1

$defaults = array(
'theme_location' => '',
'menu' => 'menu-name',
'container' => 'div',
'container_class' => '',
'container_id' => '',
'menu_class' => 'menu',
'menu_id' => '',
'echo' => true,
'fallback_cb' => 'wp_page_menu',
'before' => '',
'after' => '',
'link_before' => '',
'link_after' => '',
'items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>',
'depth' => 0,
'walker' => new My_Walker_Nav_Menu() //call walker
);
//Add this in your theme functions.php file
class My_Walker_Nav_Menu extends Walker_Nav_Menu {
function start_lvl(&$output, $depth) {
$indent = str_repeat("\t", $depth);
$output .= "\n$indent<ul class=\"dropdown\">\n";
}
}

Answer 2

you try to this code...
HTML DEMO
Reference link
Wordress Code
<nav class="navbar-collapse collapse photoshoot-menu">
<?php wp_nav_menu(array('theme_location' => 'primary','container' => ' ')); ?>
</nav>