Wordpress Menu Exchange for Mobile Layout

Question

I want to have two different menus for desktop and mobile phone users.

So, I have created two places for two menus (primary, mobile) with this function:

functions.php:

function is_register_my_menus() {
register_nav_menus(
array(
  'primary' => __( 'primary' ),
  'mobile' => __( 'mobile' )  
)
);
}
add_action( 'init', 'is_register_my_menus' ); 

So far, so good. I could create another menu with one item left out and set that menu as "mobile".

Then I installed the Wordpress plugin PHP Browser Detection, which works just fine. With that I tried to have a switching/exchange of those two menus, depending on the device.

header.php:

<nav id="nav" role="navigation" class="gross">
        <div id="knopf"><a href="#"></a></div>
        <?php if ( is_mobile() ) { wp_nav_menu( array('menu' => 'mobile' ) ); } else { wp_nav_menu( array('menu' => 'primary' ) ); }; ?>
    </nav>

Unfortunately, it shows always the primary menu, regardless of computer/desktop or mobile device. Did I do something wrong in the if/else code? I use that on my posts to exchange post_thumbnail per device, as well, and there it is working fine.

Answer 1

There isn't an is_mobile() function to my knowledge. WordPress uses a wp_is_mobile() which is probably what you're looking for. So it should look like this:

<?php if ( wp_is_mobile() ) { wp_nav_menu( array('menu' => 'mobile' ) ); } else { wp_nav_menu( array('menu' => 'primary' ) ); }; ?>

EDIT

After reviewing your question further it seems like you have a plugin installed to browser sniff for you. It does look like it uses is_mobile() but since I am unfamiliar with the plugin I would suggest going vanilla with wp_is_mobile() instead of using a plugin, who knows what could be wrong with the plugin or if the plugin is compatible with your installation.

FINAL EDIT

It turns out according to OP that the menu names were not matching.