explicit "switch to mobile theme" link with Theme Key

Question

I'm using Theme Key https://www.drupal.org/project/themekey to switch automatically between themes dependent on browser and/or OS id. Now I would like to allow the user to explicitly switch to or from to one or the other theme by clicking a link too. ThePersistant URL https://www.drupal.org/project/purl module might be helpful for this but how exactly can I go about implementing this?

EDIT 1

I followed Answer 1, added drupal_add_library('system', 'jquery.cookie'); into the already existing function marinelli_preprocess_page(&$vars) in my template.php.

I setup two ThemeKey rules like:

system:cookie = "theme=marinelli" THEME [Marinelli] 

and

system:cookie = "theme=skeleton" THEME [Skeleton]

and added following html to my page:

<p><a href="#" onclick="$.cookie('theme', 'marinelli')">Switch to Marinelli</a> <a href="#" onclick="$.cookie('theme', 'skeleton')">Switch to Skeleton</a></p>

But clicking the links, doesn't do anything, seems like I might be missing something or it might not quite work this way because href="#" doesn't actually reload the page if that was the actual idea...?

Answer 1

To make it to work with cache you can use the Mobile Cache module, at least as inspiration to make your own module using the library Mobile Detect.

https://www.drupal.org/sandbox/acy76/1962696

But you need to modify this line in the module and must look like this

_mobile_cache_add_query_string('device=' . $data['device'] . '&theme=' . $_COOKIE['theme']);

Notice that the idea is add the theme name to the cache

I'm using Authcache and Filecache

Thanks @PatrickRyan

Answer 2

One way would be to nest each theme switching rule inside another rule using

system:cookie = theme=theme1

     Theme switching rule here

system:cookie = theme=theme2

     Another theme switching rule here

You will need to set up your theme switching links to create a cookie using your method of choice, PHP or jquery.cookie

An example using jquery.cookie could be something like:

template.php:

function THEMENAME_preprocess_page(&$vars) {
  drupal_add_library('system', 'jquery.cookie');
}

Your theme switching links:

<a href="#" onclick="jQuery.cookie('theme', 'theme1'); location.reload(); return false;">Switch to Theme1</a>
<a href="#" onclick="jQuery.cookie('theme', 'theme2'); location.reload(); return false;">Switch to Theme2</a>

Keep in mind that this is not page caching friendly. If you want this to work for anonymous users, you will need to disable page caching.