Paging in wordpress themes

That’s because the $prime_cols in your theme template doesn’t exist when the pre_get_posts action is doing it’s thing.

The var_dump shows it as an int(2), int(3) or int(4) depending on which template I am in and to me that would more than suggest that is does exist at that point.

It also shows a NULL which is coming out previously (which may be where you were referring to)

See the top left and bottom right of the image linked for what I mean

What is the fix?

So… I think it goes like this.

Page one:
Run a default query ($prime_cols = NULL) this returns a resultset as it is starting at 0
Runs my custom query ($prime_cols = 2) as it is starting at 0, paging correctly set using variable

Page Two:
Run a default query ($prime_cols = NULL) this returns null / false as it is starting at 10 and only 3 items exist
Shows 404
Never runs custom query.

I guess I need to over-ride the default query rather than running a custom one. Is this possible?

I’m not sure that “default” is the right term

OK, I have a solution of sorts. I’m not entirely happy with it but I’m on a deadline. I’ll take the time to share anyway.

1. Hack the Category Templates plug in so it can identify the template it will use

2. In pre_get_posts use this to override settings for the default query

3. No more custom queries (I like this bit)

So in the Category Templates plug in replace the cat_temp function with

function cat_temp($template, $include = true) {
	global $wp_query;
	$post_obj = $wp_query->get_queried_object();

	if (is_single()) {
		$data = cat_temp_get_data();
		$categories = get_the_category($post_obj->ID);
	} else if (is_category()) {
		$data = cat_temp_get_data(true);
		$categories[0] = &get_category($post_obj->cat_ID);
	}
	$temp_data;

	// Get templates for post categories
	foreach((array)$categories as $category) {
		if ($data[$category->term_id]['template'] != '0') {
			$temp_data[$data[$category->term_id]['template']] = $data[$category->term_id]['priority']+($category->term_id/80000);
		}
	}

	// Get templates for parent categories
	foreach((array)$data as $key => $cat) {
		if ($cat['all'] == "all" && $cat['template'] != "0") {
			$id = (is_single()) ? (int)$cat['id'] : $key;
			$descendants = get_term_children($id, 'category');
			if ($descendants && in_category($descendants)) {
				$temp_data[$cat['template']] = $cat['priority']+($cat['id']/80000);
			}
		}
	}

	//print_r($temp_data);

	// Sort templates by priotiry, and return the one with the highest priority
	if (is_array($temp_data)) {
		asort($temp_data);
		$template = array_shift(array_keys($temp_data));
	}

	// If currrent post has a template, use that one instead
	if (is_single()) {
		$overRule = cat_temp_post_template($post_obj->ID);
		if ($overRule) $template = $overRule;
	}

	// Return template path
	if (!empty($template)) {
		if ($include) {
			if (file_exists(TEMPLATEPATH.$template)) {
				include(TEMPLATEPATH.$template);
				exit;
			}
		} else {
			return $template;
		}
	}
}

and use it in the pre_get_posts hook

add_filter( 'pre_get_posts', 'modify_query' );
function modify_query($query)
{

	if (!$query->is_category()) {
		return;
	}

        global $wp_the_query;
	if ( method_exists( $query, 'is_main_query' ) ) {
		if (!$query->is_main_query()) {
			return;
		}
	} else {

		if ($query !== $wp_the_query) {
			return;
		}
	}

	$category = $wp_query->get_queried_object();
	$page = (get_query_var('paged')) ? get_query_var('paged') : 1;
	$query->set('post_type', 'page');
	$query->set('category_name', $category->slug);
	$query->set('paged', $page);

	$template = cat_temp("", false);
	switch ($template) {
		case '/two-col.php':
			$query->set('posts_per_page', 2);
			$query->set('showposts', 2);
			break;
		case '/three-col.php':
			$query->set('posts_per_page', 3);
			$query->set('showposts', 3);
			break;
		case '/four-col.php':
			$query->set('posts_per_page', 4);
			$query->set('showposts', 4);
			break;
	}
}

If experienced WordPress developers don’t cough up their spines in this thread, I’ll send the Category Template changes upstream…