its possible to swicth the wp_query on category.php?

Finally:

<?php
// category.php
get_header(); 

// get the category ID
$cat_obj = $wp_query->get_queried_object();
$cat_ID = $cat_obj->term_id;

// grab which order we want from the link order
$get_order = isset($_GET["order"]) ? $_GET["order"] : NULL;

// toggle neworder if oldorder is not null
if (!is_null($get_order)){
	$neworder = $get_order ? 0 : 1;
}
?>

<!-- this is the magical swap link -->
<a href="?order=<?php echo $neworder; ?>">Swap order</a>

<?php
// if get_order is set, we have a new order for this loop, using add_filter
if (isset($get_order)) {
	// if neworder is 1, ASC, else DESC
	if ($neworder == 1){
		add_filter('posts_orderby', create_function('$a',' return " wp_posts.post_title ASC"; '));
	}else{
		add_filter('posts_orderby', create_function('$a',' return " wp_posts.post_title DESC"; '));
	}
}

// the category query, yes, paged, please
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
query_posts($query_string .'&paged='.$paged.'&cat='.$cat_ID);

// the loop
if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>

<!-- Do some ninja tricks here... -->

<?php endwhile; endif; ?>

Some facts:
– you gonna get some ugly urls: /page/3/?order=1
– Didn’t reset the query before or after the loop
– I’m using WP 3.0.1
– This is the category.php from Twenty Ten 1.1 theme
– But I’m not using get_template_part or any Twenty Ten functions
– Works fine with WP-PageNavi 2.73, but you need this code on functions.php:

add_action( 'parse_query', 'category_posts_per_page', 10, 1 );
function category_posts_per_page( $q_obj ) {
	if( is_category() )
		$q_obj->query_vars['posts_per_page'] = 2; // Change this example value
}

For more info about this action, please, read this topic. Thanks @mark/t31os!

Some related reading:

– http://wpquestions.com/question/show/id/883

– http://mitcho.com/blog/how-to/external-orders-in-wordpress-queries/

I just want to know why I cannot use a simple tricks (query_posts) on this case?

If you have ideas and want to share, please share.

Hi Mark, the problem is, I try almost every possible way to get query_posts working and nothing…

I try to merge, I try other ways I try a similar approach like your code, but I’m not using that get_template_part stuff. I should delete some files of the theme? I remove all functions of that functions.php theme. I delete loop.php and start from scratch. Everything is fine, only this category page that breaks. That code above is my current category page.

I just want a clean category page and a link to toggle the order of the posts…

The only way to get this toggle working is using that filter. But in future I’ll need to order by custom field too (I’m almost crying right now to make more weird filters for custom fields with posts per page and pagination).

The problem is on the “category.php” file? I still dont get it… I have to use that get_template_part now?

Hi Mark, thanks for your time.. here I go, this works:

<?php
// category.php
get_header();

$sidecat_id =4;

// grab which order we want from the link order
$get_order = isset($_GET["order"]) ? $_GET["order"] : NULL;

// toggle neworder if oldorder is not null
if (!is_null($get_order)){
	$neworder = $get_order ? 0 : 1;
}
?>

<!-- this is the magical swap link -->
<a href="?order=<?php echo $neworder; ?>">toggle</a>

<?php
// if get_order is set, we have a new order for this loop, using add_filter
if (isset($get_order)) {
	// if neworder is 1, ASC, else DESC
	if ($neworder == 1){
		query_posts( array_merge(
			$wp_query->query,
			array( 'posts_per_page' => 10)
		) );
	}else{
		query_posts( array_merge(
			$wp_query->query,
			array( 'posts_per_page' => 1)
		) );
	}
}

// the category query, yes, paged, please
//$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
//query_posts($query_string .'&paged='.$paged.'&cat='.$cat_ID);

// the loop
if ( have_posts() ) : while ( have_posts() ) : the_post();
?>

<h1><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h1>

<?php endwhile; endif; ?>

But when I try to swap order of the titles, nothing happens, I still got all posts ordered by date, like default category.php does:

if (isset($get_order)) {
	// if neworder is 1, ASC, else DESC
	if ($neworder == 1){
		query_posts( array_merge(
			$wp_query->query,
			array( 'orderby' => 'title', 'order' => 'asc')
		) );
	}else{
		query_posts( array_merge(
			$wp_query->query,
			array( 'orderby' => 'title', 'order' => 'desc')
		) );
	}
}

Note: I remove this code from functions.php:

add_action( 'parse_query', 'category_posts_per_page', 10, 1 );
function category_posts_per_page( $q_obj ) {
	if( is_category() )
		$q_obj->query_vars['posts_per_page'] = 2; // Example value
}

🙁

Hey Mark.. don’t work. I always get this order of posts:

test 2
order test
test 1
z test
new test