CMB2 Repeater Demo - a simple example

cmb2-repeater-demo-display-data.php

<?php
add_filter( 'the_content', 'crd_append_post_links' );
function crd_append_post_links( $content ) {
	if ( is_page() ) {
		$post_links_data = get_post_meta( get_the_ID() );
		if ( isset( $post_links_data[ 'blog_group' ][ 0 ] ) ) {
			$blog_list = maybe_unserialize( $post_links_data[ 'blog_group' ][ 0 ] );
			
			$posts_list = '<ul>';
			foreach ( $blog_list as $post_info ) {
				$posts_list .= sprintf( '<li><a href="%s">%s</a></li>', $post_info[ 'url' ], $post_info[ 'title' ] );
			}
			$posts_list .= '</ul>';
			return $content . $posts_list;
		}
	}
	
	return $content;
}

cmb2-repeater-demo-field-setup.php

<?php
add_action( 'cmb2_admin_init', 'crd_repeater_metaboxes' );
/**
 * Define the metabox and field configurations.
 */
function crd_repeater_metaboxes() {
	/**
	 * Initiate the metabox
	 */
	$cmb = new_cmb2_box( array(
		'id'            => 'repeater_demo',  // Belgrove Bouncing Castles
		'title'         => 'Repeater Demo',
		'object_types'  => array( 'page', ), // Post type
		'context'       => 'normal',
		'priority'      => 'high',
		'show_names'    => true, // Show field names on the left
	) );

	$blog_group_id = $cmb->add_field( array(
		'id'          => 'blog_group',
		'type'        => 'group',
		'repeatable'  => true,
		'options'     => array(
			'group_title'   => 'Post {#}',
			'add_button'    => 'Add Another Post',
			'remove_button' => 'Remove Post',
			'closed'        => true,  // Repeater fields closed by default - neat & compact.
			'sortable'      => true,  // Allow changing the order of repeated groups.
		),
	) );
	$cmb->add_group_field( $blog_group_id, array(
		'name' => 'Post Title',
		'desc' => 'Enter the post title for the link text.',
		'id'   => 'title',
		'type' => 'text',
	) );
	$cmb->add_group_field( $blog_group_id, array(
		'name' => 'Post URL',
		'desc' => 'Enter the url of the post.',
		'id'   => 'url',
		'type' => 'text_url',
	) );
}

cmb2-repeater-demo-full-code.php

<?php
/*
Plugin Name: CMB2 Repeater Demo
Plugin URI: http://www.damiencarbery.com
Description: Demo using repeater feature of CMB2.
Author: Damien Carbery
Version: 0.2
*/


add_action( 'cmb2_admin_init', 'crd_repeater_metaboxes' );
/**
 * Define the metabox and field configurations.
 */
function crd_repeater_metaboxes() {
	/**
	 * Initiate the metabox
	 */
	$cmb = new_cmb2_box( array(
		'id'            => 'repeater_demo',  // Belgrove Bouncing Castles
		'title'         => 'Repeater Demo',
		'object_types'  => array( 'page', ), // Post type
		'context'       => 'normal',
		'priority'      => 'high',
		'show_names'    => true, // Show field names on the left
	) );

	$blog_group_id = $cmb->add_field( array(
		'id'          => 'blog_group',
		'type'        => 'group',
		'repeatable'  => true,
		'options'     => array(
			'group_title'   => 'Post {#}',
			'add_button'    => 'Add Another Post',
			'remove_button' => 'Remove Post',
			'closed'        => true,  // Repeater fields closed by default - neat & compact.
			'sortable'      => true,  // Allow changing the order of repeated groups.
		),
	) );
	$cmb->add_group_field( $blog_group_id, array(
		'name' => 'Post Title',
		'desc' => 'Enter the post title for the link text.',
		'id'   => 'title',
		'type' => 'text',
	) );
	$cmb->add_group_field( $blog_group_id, array(
		'name' => 'Post URL',
		'desc' => 'Enter the url of the post.',
		'id'   => 'url',
		'type' => 'text_url',
	) );
}


add_filter( 'the_content', 'crd_append_post_links' );
function crd_append_post_links( $content ) {
	if ( is_page() ) {
		$post_links_data = get_post_meta( get_the_ID() );
		if ( isset( $post_links_data[ 'blog_group' ][ 0 ] ) ) {
			$blog_list = maybe_unserialize( $post_links_data[ 'blog_group' ][ 0 ] );
			
			$posts_list = '<ul>';
			foreach ( $blog_list as $post_info ) {
				$posts_list .= sprintf( '<li><a href="%s">%s</a></li>', $post_info[ 'url' ], $post_info[ 'title' ] );
			}
			$posts_list .= '</ul>';
			return $content . $posts_list;
		}
	}
	
	return $content;
}


// Verify that CMB2 plugin is active.
add_action( 'admin_notices', 'verify_cmb2_active' );
function verify_cmb2_active() {
	if ( ! defined( 'CMB2_LOADED' ) ) {
		$plugin_data = get_plugin_data( __FILE__ );
		$plugin_name = $plugin_data['Name'];
?>
<div class="notice notice-warning is-dismissible"><p>Plugin <strong><?php echo $plugin_name; ?></strong> requires <a href="https://wordpress.org/plugins/cmb2/">CMB2 plugin</a>.</p></div>
<?php
		//error_log( 'CMB2 is not active.' );
	}
}