How to check if three different categories have posts and act upon each of them

I think I want to rephrase my question to explain what is really needed in my case:

1. Category structure: 3 main categories.
2. Each main category has several sub categories
3. Each post belongs to a unique set of 3 sub categories, one from each main category

Navigation will go through each main category seperately. After choosing a subcategory of the first main category, a choice can be made for a subcategory of the second main category and after that from within the third main category.

The problem is that each subsequent choice has to ‘remember’ the previous choice. How do I do that? In the end I need a page with the only 5 posts that belong to those 3 choices.

Hello Keesie. and thanks for your reply, but I’m a little confused about the code. After choosing one of the subcats of the first top level cat, as shown at the top of this page, I need to make of choice for one of the subcategories of the second top level cat. So, then $subject= get_categories('child_of='.$current_cat); would return the subcats of the first choice, which doesn’t have subcats because it is a subcat.

So:

Animals
– Pigs
– Cats
Countries
– France
– England
Regions
– Region 1
– Region 2

A post belongs to a combination of three subcats:
Pigs/England/Region 1
Pigs/France/Region 1
Cats/England/Region 1
Cats/England/Region 2 etc.

If there are posts that belong to subcat Pigs, first I want to present a map of countries (all the subcats of Countries), and show which one has regions that has pigs or not (countries that do are colored, the ones that don’t are grey). Still I don’t want to show posts. After clicking a country I present a map of that country divided by regions, and again regions that do are colored, the ones that don’t are grey. After clicking the region (that has posts that belong to the specific animal and the specific country and specific region) I want to show the results.

Is this possible? Or sorry if I didn’t understand your code 😉

I followed your suggestion and changed the whole category structure and I can see the benefits of this. Now each post is assigned to only two categories: a subcat of Animals and one of the regions. The only thing I still don’t understand is how I can check on the category.php page if a country/region has posts that are also inside the one specific animals cat.

With the code I have now, on the page that would show the map of the country, it will show all countries that have posts and not only to the first chosen category. It will show me all countries that has animals, not just one of them.

$cat_id = get_query_var('cat');
$animal = get_category( $cat_id ); // the previously chosen animal
$countries = get_categories('hide_empty=0&exclude=1&orderby=slug&order=ASC&parent=6'); // which is the category id of countries
echo "<ul>";
foreach($countries as $country) {
	$test=get_posts('category='.$country->cat_ID);
	if ($test) {
	echo "<li class=\"".$country->cat_name."\"><a href=\"" . get_category_link($country->cat_ID) . "\"><span>". get_cat_name($country->cat_ID) ."</span></a></li>";
	} else {
	echo "<li class=\"".$country->cat_name."\"></li>";
	}
}
echo "</ul>";

After that, I’m facing the same problem with showing the regions that have posts that are also inside that particular category.

I hope you can give me some tips on how to do this. I’m struggling with this for weeks now 😉

Thanks for all that code 🙂
Before testing it, I see that you embedded part of the code for continents, but I don’t have continents, just countries and regions. Could you tell me which part of the code I should remove then? And just to be sure, am I correct that all this should go inside category.php?

Also, just noticed that for each list there is no list for if there are no posts. For those I use just empty list items so I can style them with css and they will be grey and not clickable.

Well, to be precise, those categories were just an example to explain on this forum how the website is supposed to work. But because you are helping me so much I think I will explain the actual structure 🙂

Animals
– Pigs
– Cats
Provinces
– First province name
— Region 1
— Region 2
– Second Province name
— Region 1
— Region 2

So the first map after clicking ‘Pigs’ (which is a sub level category of top level category ‘Animals’) is actually a map of one single country and the only country. This country is divided into provinces (the second top level category) which are divided into regions. So first one clicks on the link ‘Pigs’ (on index.php). Secondly there is the map of the country with clickable and unclickable provinces, depending on if a region inside that province has posts that are also part of the category ‘Pigs’. After that a map of the province is shown, divided into clickable and unclickable regions, depending on (again) if a region inside that province has posts that are also part of the category ‘Pigs’.

I hope this makes things more clear for you.

It doesn’t work exactly right yet. Whenever I’m on a page with the country map all the provinces are colored that have posts, even the ones that don’t belong to the chosen category, ie cats or pigs.

I removed the first two ‘issets’ because I think I don’t need them (correct me if I’m wrong), because on the index.php page I already made a choice like this:

<li><a href=\"" . get_category_link($subject->cat_ID) . "?show=map&type=provinces\">

Also I replaced the -> == 0 by

$postsinregions = get_posts('hide_empty=0&category='.$province->cat_ID);
if(!$postsinregions) {

because somehow it didn’t work properly.

For now I have this code, including some css I need to create the maps: code. I think it will work, except for the check if the posts belong to the first category. I think you are trying to do that with

get_posts(array( 'category__and' => array( $regio->cat_ID, $current_cat ) ) );
Am I correct?

Somehow there is a part missing.
After or just before the foreach() there should be a check like the category__and, because with every page there still is a cat between the pigs 😉