The next_posts_link() works only with original $wp_query

Question

I've got custom template that I want to display paged blog posts. This is the beginning of my file:

$wp_query = new WP_Query($args);
    if($wp_query->have_posts()){
        while($wp_query->have_posts()){ $wp_query->the_post();
            //something...
    <?php next_posts_link('Older Entries'); ?>
    <?php previous_posts_link('Newer Entries'); ?>

It works fine - it displays OLDER and NEWER links when it should. On the first page it will display only a link to older entires. On the second page both to newer entries and yet older ones etc.

But I don't want to overwrite current $wp_query... I want to use let's say $wp_query2 for this loop. And the links don't appear at all if I do this.

According to this: http://codex.wordpress.org/Function_Reference/next_posts_link they print a link to the prev/next set of posts within the current query. I assume that $wp_query2 isn't my "CURRENT QUERY" but $wp_query always is. Can I change that somehow?

UPDATE: Adding &paged=2 manually to the link causes it to correctly go to the next set of posts (next page) and on second, third etc. page previous_posts_link() works even if I use $wp_query2. So, I'm just missing next_posts_link() functionality on every page.

Answer 1

next_posts_link and previous_posts_link use the global $wp_query.

function get_next_posts_link( $label = null, $max_page = 0 ) {
    global $paged, $wp_query;

http://core.trac.wordpress.org/browser/tags/3.5/wp-includes/link-template.php#L1523

That means you need to do something like this to get those to work correctly.

$orig_query = $wp_query;
$wp_query = new WP_Query($args);
// the rest of your code
$wp_query = $orig_query;

If you are done with $wp_query for that page load there is no reason to preserve it. It should be pretty easy to copy those core functions, modify them to accept a query parameter and create your own paging functions.

Answer 2

Looking at the wordpress source, it looks like next_posts_link uses the global var $paged. My guess is that is only going to work for the primary loop.

A pretty good solution on how to make pagination work for secondary loops is here: http://weblogtoolscollection.com/archives/2008/04/19/paging-and-custom-wordpress-loops/

It involves setting the paged query var explicitly in the query, like this:

<h3>Recent Articles</h3>
<ul>
<?php 
$temp = $wp_query;
$wp_query= null;
$wp_query = new WP_Query();
$wp_query->query('showposts=5'.'&paged='.$paged);
?>

Hope that helps.

Answer 3

I ran into the same issue. I have nested loops, so in the inner loop I am using $wp_query = new WP_Query($args); instead of the global WP_Query. The solution I used was to explicitely pass max_num_pages to the next_posts_link function. This has been mentioned in the comments by Andy Giesler as well.

Solution:

<?php  
  //outer loop  
    //some outer code
    //inner loop starts
      $inner_query = new WP_Query( 
                array('posts_per_page' => '4', 'paged' => get_query_var('paged')) 
            ); 
        // ...show all posts etc code  
      previous_posts_link( 'Older posts' ); 
      next_posts_link( 'Newer posts', $inner_query->max_num_pages ); //Note this
    //inner loop finishes
    //some other outer loop code  
  //outer loop finishes
?>  

The reason we have to do this is that wordpress internally use global WP_query's $max_page property, which if is undefined then the default will be $max_page = 0