The "Child Pages Shortcode" plugin, block template

Question

So I have decided on using the Child Pages Shortcode plugin, a plugin that pulls the ID, tittle, thumbnail, excerpt, etc of the child pages. The plugins author explains that he encourages customization of his plugin.

The templates author describes that you should be able to build your own template, something that I don´t understand to 100%, but I have been able to change the existing template so that it generates <li> of the individual children. Now I need to add a container for all of my list items, it would look something like

<div class="row-fluid">
<ul class="thumbnails">
       <li class="span3">
       <li class="span3">
       <li class="span3">
       <li class="span3">
    </ul>
</div>

EDIT: I added the suggested changes, but it gives me the following error: Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'wpse_113253_child_pages_shortcode_template' not found or invalid function name....

Source code of the Child Pages Shortcode plugin with my customizations and the suggested fix:

<?php
/*
Plugin Name: Child Pages Shortcode
Author: Takayuki Miyauchi
Plugin URI: http://wpist.me/wp/child-pages-shortcode/
Description: You can use shortcode for display child pages from the page.
Version: 1.7.0
Author URI: http://wpist.me/
Domain Path: /languages
Text Domain: child-pages-shortcode
*/

new childPagesShortcode();

class childPagesShortcode {

private $ver = '1.1.4';

function __construct()
{
    add_shortcode("child_pages", array(&$this, "shortcode"));
    add_action("init", array(&$this, "init"));
    add_action("wp_enqueue_scripts", array(&$this, "wp_enqueue_scripts"));
    add_filter("plugin_row_meta", array(&$this, "plugin_row_meta"), 10, 2);
    // Wrap <li> tags around each template item.
    add_filter( 'child-pages-shortcode-template', 'wpse_113253_child_pages_shortcode_template' );
    // Wrap <div> and <ul> tags around everything.
    add_filter( 'child-pages-shortcode-output','wpse_113253_child_pages_shortcode_output' );
}

public function init()
{
    add_post_type_support('page', 'excerpt');
}

public function wp_enqueue_scripts()
{
    $css = apply_filters(
        "child-pages-shortcode-stylesheet",
        plugins_url("style.css", __FILE__)
    );
wp_register_style(
    'child-pages-shortcode-css',
    $css,
    array(),
    $this->ver,
    'all'
);
wp_enqueue_style('child-pages-shortcode-css');

$js = apply_filters(
    "child-pages-shortcode-js",
    plugins_url("script.js", __FILE__)
);
wp_register_script(
    'child-pages-shortcode',
    $js,
    array('jquery'),
    $this->ver,
    false
);
wp_enqueue_script('child-pages-shortcode');
}

public function shortcode($p, $template = null)
{
if( !isset($p['id']) || !intval($p['id']) ){
    $p['id'] = get_the_ID();
}
if (!isset($p['size']) || !$p['size']) {
    $p['size'] = 'thumbnail';
}
if (!isset($p['width']) || !intval($p['width'])) {
    $p['width'] = "50%";
}
if (!isset($p['disable_shortcode']) || !$p['disable_shortcode']) {
    add_filter("child-pages-shortcode-output", "do_shortcode");
}
return $this->display($p, $template);
}

private function display($p, $block_template)
{
global $post;

$html = '';

if ($block_template) {
    $template = $block_template;
    $template = str_replace('<p>', '', $template);
    $template = str_replace('</p>', '', $template);
    $template = apply_filters(
        'child-pages-shortcode-template',
        $template,
        $p
    );
} else {
    $template = apply_filters(
        'child-pages-shortcode-template',
        $this->get_template(),
        $p
    );
    $html = sprintf(
        '<div class="row-fluid">'
    );
}

$args = array(
    'post_status' => 'publish',
    'post_type' => 'page',
    'post_parent' => $p['id'],
    'orderby' => 'menu_order',
    'order' => 'ASC',
    'nopaging' => true,
);
$args = apply_filters('child-pages-shortcode-query', $args, $p);

$pages = get_posts($args);
foreach ($pages as $post) {
    setup_postdata($post);
    $post = apply_filters('child_pages_shortcode_post', $post);
    $url = get_permalink($post->ID);
    $img = get_the_post_thumbnail($post->ID, $p['size']);
    $img = preg_replace( '/(width|height)="\d*"\s/', "", $img);
    $tpl = $template;
    $tpl = str_replace('%width%', esc_attr($p['width']), $tpl);
    $tpl = str_replace('%post_id%', intval($post->ID), $tpl);
    $tpl = str_replace('%post_title%', $post->post_title, $tpl);
    $tpl = str_replace('%post_url%', esc_url($url), $tpl);
    $tpl = str_replace('%post_thumb%', $img, $tpl);
    if (isset($p['disabled_excerpt_filters']) && $p['disabled_excerpt_filters']) {
        $tpl = str_replace('%post_excerpt%', $post->post_excerpt, $tpl);
    } else {
        $tpl = str_replace('%post_excerpt%', get_the_excerpt(), $tpl);
    }
    $html .= $tpl;
}

wp_reset_postdata();

if (!$block_template) {
    $html .= '</div><!--row-fluid Child Pages Shortcode-->';
}

return apply_filters("child-pages-shortcode-output", $html);
}

private function get_template()
{
$html = "\n";
$html .= '<li class="span3">';
$html .= '<div id="child_page-%post_id%" class="thumbnail">';
$html .= '<div class="post_thumb"><a href="%post_url%">%post_thumb%</a></div>';
$html .= '<div class="caption">';
$html .= '<h4><a href="%post_url%">%post_title%</a></h4>';
$html .= '<p>%post_excerpt%</p>';
$html .= '</div><!-- .caption  -->';
$html .= '</div><!-- .child_page-container -->';
$html .= '</div><!-- #child_page-%post_id%" -->';
$html .= "\n";

if ($tpl = get_post_meta(get_the_ID(), 'child-pages-template', true)) {
    $html = $tpl;
}

return $html;
}
/**
 * Wrap <li> tags around each template item.
 */
function wpse_113253_child_pages_shortcode_template( $template ) {
return "<li>$template</li>\n";
}

/**
* Wrap a <div> and <ul> tags around everything.
*/
function wpse_113253_child_pages_shortcode_output( $html ) {
return "
<div class='row-fluid'>
<ul class='thumbnails'>
    $html
</ul><!-- end .thumbnails -->
</div><!-- end .row-fluid -->
";
}

public function plugin_row_meta($links, $file)
{
$pname = plugin_basename(__FILE__);
if ($pname === $file) {
    $links[] = sprintf(
        '<a href="%s">Donate</a>',
        'https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclickhosted_button_id=8RADH554RPKDU'
    );
}
return $links;
}

} // end childPagesShortcode()

// eof

Answer 1

Try this:

// Wrap <li> tags around each template item.
add_filter( 'child-pages-shortcode-template', 'wpse_113253_child_pages_shortcode_template' );

// Wrap <div> and <ul> tags around everything.
add_filter( 'child-pages-shortcode-output', 'wpse_113253_child_pages_shortcode_output' );

/**
 * Wrap <li> tags around each template item.
 */
function wpse_113253_child_pages_shortcode_template( $template ) {
    return "<li>$template</li>\n";
}

/**
 * Wrap a <div> and <ul> tags around everything.
 */
function wpse_113253_child_pages_shortcode_output( $html ) {
    return "
<div class='row-fluid'>
    <ul class='thumbnails'>
        $html
    </ul><!-- end .thumbnails -->
</div><!-- end .row-fluid -->
";
}

Note: I didn't install the plugin to test this code.