Slider - Homepage

[Gih]

I’m learning how to use WordPress Settings API, I can create pages and sub-pages, save/update fields in DB.

Now I’m trying to learn how to integrate the bootstrap slider into the API Settings. I put some of the code on Github:

GitHub - GiseleFerreiraLima/estudos: Apenas para estudos pessoais em contato...

All the Jquery and selection of the images is ok. New inputs are created dynamically when images are selected. Each field is created with the input name="my_image_URL[]".

My difficulty

I am not getting the names and put in the variable $UrlsToSave

function tema_home_imgs(){   
        $UrlsSavedInDB = esc_attr( get_option( 'imagens_home' ) );

        include( get_template_directory() . '/inc/templates/selecao_imagens.php');

        if ( isset( $_POST['my_image_URL'] ) ) {
            $UrlsToSave= htmlspecialchars(json_encode($_POST['my_image_URL']));

             echo '<input name="imagens_home" value="'.$UrlsToSave.'" style="width:300px"/>';
        }   
 }

In the theme_home_imgs() function, I want to put the $ _POST['my_image_URL'] array in the variable $UrlsToSave.

Soon after I convert this array into JSON to save in single input of Settings API:

$UrlsToSave= htmlspecialchars (json_encode ($ _ POST ['my_image_URL']));
Echo '<input name="image_home" value="'.$UrlsToSave. '" Style="width: 300px" />';

It turns out that the array always remains empty after the submit, print_r or var_dump return empty.

[Gih]

Please, any tips?
I have been trying for some days