pagination elements not displaying in WordPress loop - php

Question

I have the following code:
$attr = array(
'align' => 'left',
'class' => 'thumbnail imageRight',
'width' => 350,
'height' => 350
);
$post_query = array ( 'post_type' => 'post' );
$posts = new WP_Query ( $post_query );
if($posts->have_posts()){
while($posts->have_posts()){
$posts->the_post();
?>
<div class="post">
<?php the_post_thumbnail('medium', $attr); ?>
<h1><?php the_title(); ?></h1>
<p><?php the_excerpt(); ?></p>
</div>
<?php
}
next_posts_link('« Older Entries');
previous_posts_link('Newer Entries »');
}
Which can be seen in action here. This page displays currently 3 of the 21 posts in the database. How ever there is no pagination.
Can some one tell me why?

Answer 1

Both next_posts_link and previous_posts_link use the global $wp_query and $paged. You have to chase function calls around the source code to see that (but it is pretty obvious with next_post_links). They don't work with custom queries but I believe you can cheat.
$old_wpq = $wp_query;
$wp_query = new WP_Query ( $post_query );
// your loop
$wp_query = $old_wpq;
Try that.
There is a related thread wordpress.stackexchange.com.
https://wordpress.stackexchange.com/questions/77661/next-posts-link-works-only-with-original-wp-query/77666#77666

Answer 2

<?php
global $wp_query;
$paged = ( get_query_var('paged') ) ? get_query_var('paged') : 1;
$args = array(
'post_type' => 'post', //Post type
'posts_per_page' => 3, //How many post u want to display per page
'paged' => $paged
);
$the_query = new WP_Query( $args );
if ( $the_query->have_posts() ) {
while ( $the_query->have_posts() ) {
$the_query->the_post();
$url = wp_get_attachment_url( get_post_thumbnail_id($post->ID) );
?>
<img src="<?=$url?>" width="350" height="350" class="thumbnail imageRight"/>
<h1><?php the_title(); ?></h1>
<p><?php the_excerpt(); ?></p>
<?php } } ?>
<div class="pagination">
<?php
global $wp_query;
$big = 999999999; // need an unlikely integer
echo paginate_links( array(
'base' => str_replace( $big, '%#%', esc_url( get_pagenum_link( $big ) ) ),
'format' => '?paged=%#%',
'current' => max( 1, get_query_var('paged') ),
'total' => $wp_query->max_num_pages
) );
?>
</div>