Creating a new page and automatically associating it with a template in WordPress

Question

I've got three page templates called "Simple", "Front", and "Form" and I would like to add a shortcut in the admin side bar to directly create a page that would be associated with any of these templates. So below "Add new" there would be:

• Add new Simple Page
• Add new Front Page
• Add new Form Page

I've searched for it on Google but can't find any information. Is it possible to do this in WordPress?

Answer 1

I found this question very interesting ,So here is what i have done to make this possible.

Fetch page template and add them as sub menu of Post type page.

function addTemplateAddNewSubMenu() {

    global $submenu;

    // here we are fetching all page template from current activated theme.
    $templates = wp_get_theme()->get_page_templates( 'page' );

    foreach ( $templates as $filename => $title ) {

        if ( $filename != 'default' && $filename != '' ) {

                // add page-template filename as query string to add new page link.
                $url = 'post-new.php?post_type=page&template=' . $filename;

                $submenu['edit.php?post_type=page'][] = array( 'Add new ' . $title , 'manage_options', $url );
        }
    }
}

add_action( 'admin_menu', 'addTemplateAddNewSubMenu' );

I have added page template as query string to

/wp-admin/post-new.php?post_type=page&template=template-contact.php

Making page template dropdown selected by jQuery and template Query string.

add_action( 'admin_head','selectPageTemplate' );

function selectPageTemplate() {

    global $pagenow;

    if ( $pagenow == 'post-new.php' ) {

        if ( get_post_type() == 'page' && isset($_GET['template']) ) {

            $template = $_GET['template']; ?>

            <script>
                jQuery(function($){
                    $('#page_template').val('<?php echo $template;?>');
                });
            </script>

            <?php
        }
    }

}

Answer 2

Here's an example how to set the page template, for new pages, through the custom wpse_page_template GET parameter:

https://examle.tld/wp-admin/post-new.php?post_type=page&wpse_page_template=tpl-test.php

We can hook into the save_post_page hook and target the auto-draft status:

add_action( 'save_post_page', function (  $post_ID, $post, $update )
{
    // Target 'auto-draft' status only
    if ( 'auto-draft' !== get_post_status( $post ) )
        return $post_ID;

    // User input
    $input_tpl = filter_input( INPUT_GET, 'wpse_page_template', FILTER_SANITIZE_STRING );
    $input_tpl = sanitize_file_name( $input_tpl );

    // Get current page templates
    $page_templates = wp_get_theme()->get_page_templates( $post );

    // Nothing to do if user tries a non a valid page template
    if ( ! isset( $page_templates[$input_tpl] ) )
        return $post_ID;

    // Update the user defined page template
    update_post_meta( $post_ID, '_wp_page_template', $input_tpl );

    return $post_ID;

}, 10, 3 );

This approach could be extended for custom post types in WordPress 4.7+.