How to use Metabox checkbox to add page ids in array?

What I’m trying to do is for a dual-language website. This particular language, Papiamento, isn’t supported by WordPress. Therefore, the client had to create two separate pages, in English and Pap. What I did was to code it like that to display English or Pap menu for each page.

Like this, in header.php:

` <?php

if( is_page( array(‘salon-and-spa-pap’, ‘tocante-nos’, ‘testimonio’, ‘tuma-contacto-cu-nos’, ‘galeria’, ‘tratamentonan-di-masahe’, ‘tratamentonan-spa-di-curpa’, ‘servicionan-di-boda’, ‘tratamentonan-spa-di-cara’, ‘wowo-lip-nek’, ‘cuido-di-man’, ‘tratamento-di-huna’, ‘tratamento-di-huna-di-pia’, ‘cuido-di-pia’, ‘salon-p’, ‘spa-etiquette-pap’, ‘wax-p’, ‘reserva-un-tratamento’)) ) {
wp_nav_menu(array( ‘theme_location’ => ‘menu_top_pap’ ) );
} else {
wp_nav_menu(array( ‘theme_location’ => ‘secondary-menu’ ) );
}

?>`

However, the problem is that the client will have to keep going back to header.php to add another page slug every time she create a new page. Therefore, I created a Metabox plugin for that. I made a Metabox checkbox so that everytime a page is intended for Papiamento language, the client can just check the box and either the page id or slug will be added to the code above.

I found another question (https://wordpress.stackexchange.com/questions/71043/listing-pages-with-checkboxes-in-a-metabox-and-saving-them) that might be similar to what I was looking for but it didn’t work for me.

Here’s my metabox function based on this article (https://themefoundation.com/wordpress-meta-boxes-guide/).

`<?php
function prfx_custom_meta() {
add_meta_box( ‘prfx_meta’, __( ‘Papiamento Page Box’, ‘prfx-textdomain’ ), ‘prfx_meta_callback’, ‘page’, ‘normal’, ‘low’ );
}
add_action( ‘add_meta_boxes’, ‘prfx_custom_meta’ );

function prfx_meta_callback( $post ) {
wp_nonce_field( basename( __FILE__ ), ‘prfx_nonce’ );
$prfx_stored_meta = get_post_meta( $post->ID );
$checkfield = maybe_unserialize( get_post_meta($post->ID, “checkfield”, true) );
?>

<p>
<span class=”prfx-row-title”><?php _e( ‘Pap Box’, ‘prfx-textdomain’ )?></span>
<div class=”prfx-row-content”>
<label for=”meta-checkbox”>
<input type=”checkbox” name=”meta-checkbox” id=”meta-checkbox” value=”yes” <?php if ( isset ( $prfx_stored_meta[‘meta-checkbox’] ) ) checked( $prfx_stored_meta[‘meta-checkbox’][0], ‘yes’ ); ?> />
<?php _e( ‘Check if this page is Papiamento’, ‘prfx-textdomain’ )?>
</label>

</div>
</p>
<?php
}

/**
* Saves the custom meta input
*/
function prfx_meta_save( $post_id ) {

// Checks save status
$is_autosave = wp_is_post_autosave( $post_id );
$is_revision = wp_is_post_revision( $post_id );
$is_valid_nonce = ( isset( $_POST[ ‘prfx_nonce’ ] ) && wp_verify_nonce( $_POST[ ‘prfx_nonce’ ], basename( __FILE__ ) ) ) ? ‘true’ : ‘false’;

// Exits script depending on save status
if ( $is_autosave || $is_revision || !$is_valid_nonce ) {
return;
}

// Checks for input and sanitizes/saves if needed

// Checks for input and saves
if( isset( $_POST[ ‘meta-checkbox’ ] ) ) {
update_post_meta( $post_id, ‘meta-checkbox’, ‘yes’ );
} else {
update_post_meta( $post_id, ‘meta-checkbox’, ” );
}

}
add_action( ‘save_post’, ‘prfx_meta_save’ );`

Therefore, I’ve been trying to add pages to header.php. Help!!!