display custom taxonomies limited to custom post type?

Question

i have a stupid situation, where i somehow can't find a solution and would really need some help!

So... i'm working on a project, where i have in addition to Post and Pages two Custom post types: Photos and Events.

I have created a custom taxonomy named "Tags". This taxonomy is applied to Post, Pages, Photos and Events... so basically you can give everything a Tag and you can chose everywhere from tags, that are being used elsewhere (example: if you give some tags in the Events, then you can later chose the same Tags in Photos).

The Idear is to show everywhere related stuff. So if you are on a Event, you will see in the sidebar related news, photos, even page entries...and so on...

NOW i want to display in the Photo - section only the tags, that were already used in the Custom post type Photos. Not all of them (there are some tags in Events, that have never been used in photos). So one could chose to see only photos base on a Tag...

I don't have any code yet... although i'm not a newbi in wordpress, a this point i don't even know where to start.

how can one display a list of tags, that are a custom taxonomy, limited by a custom post type?!

Any suggestion would be really nice!

Answer 1

To use the built-in tag functionality with a custom post type, you need to add this argument when registering your post type:

'taxonomies' => array( 'post_tag' ),

So to register a post type events, you'd do (eg):

register_post_type( 'events', array(
    'show_ui' => true,
    'taxonomies' => array( 'post_tag' )
   // etc ...
) );

Answer 2

So, i have figured out my problem, and come up with this function

function getCustomTaxonomy($posttype,$taxonomy) { $custompostsid = get_posts('post_type='.$posttype);

$i=0;
$j=0;

foreach ($custompostsid as $post)
{  
    setup_postdata($post);

    $customtags = wp_get_post_terms( $post->ID , $taxonomy);

        foreach ($customtags as $tag) 
        {
            $tagid[$j]=$tag->term_id; 
            $j++;
        }

    $i++;
}

$alltagsid=array_unique($tagid);

$blogurl=get_bloginfo('url');

$nummberofelements=count($alltagsid);

$k=0;

foreach ($alltagsid as $onetagid)
{

 $array = get_term_by('id', $onetagid, $taxonomy, 'ARRAY_A'); 
 $tagname=print_r($array[name],true);
 $tagcount=print_r($array[count],true);
 $taglink=$blogurl."/?".$taxonomy."=".$tagname."&type=".$posttype;

 echo "<a class='taxonomy-link' href='".$taglink."'>";
     echo $tagname." (".$tagcount.")";
 echo "</a>";
 $k++;

 if ($k<$nummberofelements) echo ", ";
}

}

i works, but i know it's not the best way to do it... cos if you have a lot of post and tags, it could get havy... so i'm still searching, but until i find a better way, this should do it :)

feel free, to optimize the code ;)

best regards

Answer 3

Have you seen this: http://wordpress.org/support/topic/passing-current-single_tag_title-as-variable-into-new-wp_query

it may help to get you started perhaps?