Keith S.

<p>The standard WordPress template tags used for post navigation (next_post, previous_post, next_post_link, and previous_post_link) don’t offer this functionality, leaving you with nothing returned if there isn’t a post.  This plugin changes that.</p>
<p>NOTE!!!  This plugin only works (without a hack in your template) on single post pages.</p>
<p>You can find the plugin home page (and leave comments) <a href="http://keithsolomon.net/plr/" rel="nofollow ugc">here</a>.</p>
<h3>Usage</h3>
<p>plr_[next|previous]_post_link(‘format’, ‘link’, ‘in_same_cat’, ‘excluded_categories’)</p>
<h3>Example</h3>
<p>This would show “Next Post Title →” as a link if there was a post that came after the currently-viewed post, or “next post:” as plain text if the current post is the most recent.</p>
<h3>Parameters</h3>
<p>This plugin uses the same parameters and format as the next_post and previous_post WordPress functions.  For more info on these functions, please visit the <a href="https://codex.wordpress.org/Template_Tags/next_post_link" rel="nofollow ugc">codex</a>.</p>


Post Links Redux

Display text instead of nothing if there isn't a next or previous post for the currently-displayed post.

IMPORTANT NOTES

>THIS PLUGIN IS NO  …

Scott Reilly

<p>This plugin adds “← Previous” and “Next →” links to the “Edit Post” admin page if a previous and next post are present, respectively. The link titles (visible when hovering over the links) reveal the title of the previous/next post. The links link to the “Edit Post” admin page for the previous/next posts so that you may edit them.</p>
<p>By default, a previous/next post is determined by the next lower/higher valid post based on the date the post was created and which is also a post the user can edit. Other post criteria such as post type (draft, pending, etc), publish date, post author, category, etc, are not taken into consideration when determining the previous or next post.</p>
<p>Users can customize how post navigation ordering is handled via the “Screen Options” panel available at the top of every page when editing a post. A dropdown presents options to order navigation by: ‘ID’, ‘menu_order’, ‘post_date’, ‘post_modified’, ‘post_name’, and ‘post_title’. Post navigation can further be customized via filters (see Filters section).</p>
<p>NOTE: Be sure to save the post currently being edited (if you’ve made any changes) before navigating away to the previous/next post!</p>
<p>Links: <a href="http://coffee2code.com/wp-plugins/admin-post-navigation/" rel="nofollow ugc">Plugin Homepage</a> | <a href="https://wordpress.org/plugins/admin-post-navigation/" rel="ugc">Plugin Directory Page</a> | <a href="https://github.com/coffe2code/admin-post-navigation/" rel="nofollow ugc">GitHub</a> | <a href="http://coffee2code.com" rel="nofollow ugc">Author Homepage</a></p>
<h3>Filters</h3>
<p>The plugin is further customizable via six filters. Such code should ideally be put into a mu-plugin or site-specific plugin (which is beyond the scope of this readme to explain).</p>
<h4>c2c_admin_post_navigation_orderby (filter)</h4>
<p>The ‘c2c_admin_post_navigation_orderby’ filter allows you to change the post field used in the ORDER BY clause for the SQL to find the previous/next post. By default this is ‘post_date’ for non-hierarchical post types (such as posts) and ‘post_title’ for hierarchical post types (such as pages). If you wish to change this, hook this filter. Note: users can customize the post navigation order field for themselves on a per-post type basis via “Screen Options” (see FAQ and screenshot for more info).</p>
<p>Arguments:</p>
<ul>
<li>$field (string) The current ORDER BY field</li>
<li>$post_type (string) The post type being navigated</li>
<li>$user_id (int) The user’s ID</li>
</ul>
<p>Example:</p>
<pre><code>/**
 * Modify how Admin Post Navigation orders posts for navigation by changing the
 * ordering of pages by 'menu_order'.
 *
 * @param string $field     The field used to order posts for navigation.
 * @param string $post_type The post type being navigated.
 * @param int    $user_id.  The user's ID.
 * @return string
 */
function custom_order_apn( $field, $post_type, $user_id ) {
    // Only change the order for the 'page' post type.
    if ( 'page' === $post_type ) {
        $field = 'menu_order';
    }

    return $field;
}
add_filter( 'c2c_admin_post_navigation_orderby', 'custom_order_apn', 10, 3 );
</code></pre>
<h4>c2c_admin_post_navigation_post_statuses (filter)</h4>
<p>The ‘c2c_admin_post_navigation_post_statuses’ filter allows you to modify the list of post_statuses used as part of the search for the prev/next post. By default this array includes ‘draft’, ‘future’, ‘pending’, ‘private’, and ‘publish’. If you wish to change this, hook this filter. This is not typical usage for most users.</p>
<p>Arguments:</p>
<ul>
<li>$post_statuses (array) The array of valid post_statuses</li>
<li>$post_type (string) The post type</li>
</ul>
<p>Example:</p>
<pre><code>/**
 * Modify Admin Post Navigation to allow and disallow certain post statuses from being navigated.
 *
 * @param array  $post_statuses Post statuses permitted for admin navigation.
 * @param string $post_type     The post type.
 * @return array
 */
function change_apn_post_status( $post_statuses, $post_type ) {
    // Add a post status.
    // Note: by default these are already in the $post_statuses array: 'draft', 'future', 'pending', 'private', 'publish'
    $post_statuses[] = 'trash';

    // Remove post status(es).
    $post_statuses_to_remove = array( 'draft' ); // Customize here.
    if ( 'page' === $post_type ) {
        $post_statuses_to_remove[] = 'pending';
    }
    foreach ( $post_statuses_to_remove as $remove ) {
        if ( false !== $index = array_search( $remove, $post_statuses ) ) {
            unset( $post_statuses[ $index ] );
        }
    }

    return array_values( $post_statuses );
}
add_filter( 'c2c_admin_post_navigation_post_statuses', 'change_apn_post_status', 10, 2 );
</code></pre>
<h4>c2c_admin_post_navigation_post_types (filter)</h4>
<p>The ‘c2c_admin_post_navigation_post_types’ filter allows you to modify the list of post_types used as part of the search for the prev/next post. By default this array includes all available post types. If you wish to change this, hook this filter.</p>
<p>Arguments:</p>
<ul>
<li>$post_types (array) The array of valid post_types</li>
</ul>
<p>Examples:</p>
<pre><code>/**
 * Modify Admin Post Navigation to only allow navigating strictly for posts.
 *
 * @param array $post_types Post types that should have admin post navigation.
 * @return array
 */
function change_apn_post_types( $post_types ) {
    return array( 'post' );
}
add_filter( 'c2c_admin_post_navigation_post_types', 'change_apn_post_types' );



/**
 * Modify Admin Post Navigation to disallow navigation for the 'recipe' post type.
 *
 * @param array $post_types Post types that should have admin post navigation.
 * @return array
 */
function remove_recipe_apn_post_types( $post_types ) {
    if ( isset( $post_types['recipe'] ) ) {
        unset( $post_types['recipe'] ); // Removing a post type
    }
    return $post_types;
}
add_filter( 'c2c_admin_post_navigation_post_types', 'remove_recipe_apn_post_types' );
</code></pre>
<h4>c2c_admin_post_navigation_prev_text (filter)</h4>
<p>The ‘c2c_admin_post_navigation_prev_text’ filter allows you to change the link text used for the ‘Previous’ link. By default this is ‘← Previous’.</p>
<p>Arguments:</p>
<ul>
<li>$text (string) The ‘previous’ link text.</li>
</ul>
<p>Example:</p>
<pre><code>/**
 * Changes the text for the 'previous' link to 'Older' output by the Admin Post Navigation plugin.
 *
 * @param string $text The text used to indicate the 'next' post.
 * @return string
 */
function my_c2c_admin_post_navigation_prev_text( $text ) {
    return 'Older';
}
add_filter( 'c2c_admin_post_navigation_prev_text', 'my_c2c_admin_post_navigation_prev_text' );
</code></pre>
<h4>c2c_admin_post_navigation_next_text (filter)</h4>
<p>The ‘c2c_admin_post_navigation_next_text’ filter allows you to change the link text used for the ‘Next’ link. By default this is ‘Next →’.</p>
<p>Arguments:</p>
<ul>
<li>$text (string) The ‘next’ link text.</li>
</ul>
<p>Example:</p>
<pre><code>/**
 * Changes the text for the 'next' link to 'Newer' output by the Admin Post Navigation plugin.
 *
 * @param string $text The text used to indicate the 'next' post.
 * @return string
 */
function my_c2c_admin_post_navigation_next_text( $text ) {
    return 'Newer';
}
add_filter( 'c2c_admin_post_navigation_next_text', 'my_c2c_admin_post_navigation_next_text' );
</code></pre>
<h4>c2c_admin_post_navigation_display (filter)</h4>
<p>The ‘c2c_admin_post_navigation_display’ filter allows you to customize the output links for the post navigation.</p>
<p>Arguments:</p>
<ul>
<li>$text (string) The current output for the prev/next navigation link</li>
</ul>
<p>Example:</p>
<pre><code>/**
 * Change the markup displayed by the Admin Post Navigation plugin.
 *
 * @param string $text The text being output by the plugin.
 * @return string
 */
function override_apn_display( $text ) {
    // Simplistic example. You could preferably make the text bold using CSS.
    return '<strong>' . $text . '</strong>';
}
add_filter( 'c2c_admin_post_navigation_display', 'override_apn_display' );
</code></pre>


Admin Post Navigation

Adds links to navigate to the next and previous posts when editing a post in the WordPress admin.

Post Links Redux vs Admin Post Navigation