pagination links not displaying

Question

I'm unable to get my 'next_posts_link()' and 'previous_posts_link()' to display. So far I've tried the standard first debug by deactivating all plugins and clearing the cache, I've also tried removing the optional parameters from the call. And I've also tried using wp-pagenavi, which does display but oddly only when I set my Reading options to show 1 post per page and even then it only shows 2 page links. The site I'm having the problem with is pixelsandtea.com and here's the code on my home template page.

<?php get_header(); ?>
<div id="main-inner">
<ul class="mcol" id="mcol">
        <?php
            $args = array( 'post_type' => array( 'post', 'portfolio', 'news' ) );
            $loop = new WP_Query( $args );
            while ( $loop->have_posts() ) : $loop->the_post();
        ?>
        <li class="article preview" id="post-<?php the_ID(); ?>">
            <h2 class="articleTitle"><a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></h2>
            <?php $content = $post->post_content;
            $searchimages = '~<img [^>]* />~';
            preg_match_all( $searchimages, $content, $pics );
            $iNumberOfPics = count($pics[0]);
            if ( $iNumberOfPics > 0 ) { ?>
                <a href="<?php the_permalink(); ?>" class="thumb" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><img src="<?php bloginfo('template_directory'); ?>/scripts/timthumb.php?src=<?php echo get_post_meta($post->ID, "thumb", $single = true); ?>&w=279&zc=1" alt="<?php the_title(); ?>" /></a><?php
            }
            the_excerpt(); ?>
            <div class="postmetadata">
                Posted: <?php the_time(__('l, jS F, Y')) ?>&nbsp;&#721;&nbsp;<?php printf(__('Filed under: %s'), get_the_category_list(', ')); ?>&nbsp;&#721;&nbsp;<?php the_tags(); ?><br />
                <?php comments_popup_link(__('No commentaries for this post yet. You could be the first!'), __('1 Comment'), __('% Comments'), '', __('Comments are closed') ); ?><?php edit_post_link(__('Edit this entry'), '&nbsp;&#721;&nbsp;', ''); ?>                         
            </div>
        </li>
        <?php endwhile; ?>
        </ul>
        <div class="clear"></div> 
        <div id="nav">
            <div id="navleft"><?php next_posts_link() ?><div class='clear' style='clear:left;'></div></div>
            <div id="navright"><?php previous_posts_link() ?><div class='clear' style='clear:right;'></div></div>
        </div>
</div>
<?php get_footer(); ?>

Thank's all!

Answer 1

You need to do a little "hack" to get pagination to work for your custom loop.

After you define $loop, do the following:

<?php
// globalize $wp_query
global $wp_query;
// copy $wp_query into a temporary variable
$temp_wp_query = $wp_query;
// nullify $wp_query
$wp_query = null;
// move $loop into $wp_query
$wp_query = $loop;
?>

At this point, your posts_nav_link() should work as expected.

Now, after the loop, swap the original object back into $wp_query, so that everything else on the page that is query-dependent will work properly:

<?php
// restore original $wp_query
$wp_query = $temp_wp_query;
?>

Answer 2

Try replacing those next/prev tags with this:

<?php next_posts_link('&laquo; Older Entries') ?>
<?php previous_posts_link('Newer Entries &raquo;') ?>