[WordPress] An example interface used to define methods for the WordPress Settings API

## 1-interface-acme-setting.php
<?php

interface Acme_Setting {

	public function register();
	public function display();
	public function sanitize( $input );

}

## 10-company-name.php
<?php
/**
 * Represents the partial view for where users can enter their company's name.
 *
 * @since      1.0.0
 *
 * @subpackage Acme_Company/views/partials
 * @package    Acme_Company
 *
 */
?>

<input type="text" name="acme_company[name]" value="<?php echo $name; ?>" placeholder="Company Name" />

## 11-plugin-bootstrap-refactored.php
<?php

/**
 * The plugin bootstrap file
 *
 * This file is read by WordPress to generate the plugin information in the plugin
 * dashboard. This file also includes all of the dependencies used by the plugin,
 * registers the activation and deactivation functions, and defines a function
 * that starts the plugin.
 *
 * @link              http://tommcfarlin.com/interface-for-the-wordpress-settings-api/
 * @since             1.0.0
 * @package           Acme_Company
 *
 * @wordpress-plugin
 * Plugin Name:       Acme Company
 * Plugin URI:        http://tommcfarlin.com/interface-for-the-wordpress-settings-api/
 * Description:       An example for how to use object-oriented principles with the WordPress Settings API.
 * Version:           1.0.0
 * Author:            Tom McFarlin
 * Author URI:        https://tommcfarlin.com
 * License:           GPL-2.0+
 * License URI:       http://www.gnu.org/licenses/gpl-2.0.txt
 */

// If this file is called directly, abort.
if ( ! defined( 'WPINC' ) ) {
	die;
}

include_once plugin_dir_path( __FILE__ ) . 'interfaces/interface-acme-setting.php';
include_once plugin_dir_path( __FILE__ ) . 'classes/class-acme-company-dashboard.php';
include_once plugin_dir_path( __FILE__ ) . 'classes/settings/class-acme-company-name.php';

/**
 * Begins execution of the plugin.
 *
 * Since everything within the plugin is registered via hooks,
 * then kicking off the plugin from this point in the file does
 * not affect the page life cycle.
 *
 * @since    1.0.0
 */
function run_acme_company() {

	$plugin = new Acme_Company_Dashboard();
	$plugin->run();

}
run_acme_company();

## 2-implementing-the-interface.php
<?php

class Acme_Company_Name implements Acme_Setting {

	public function register() {
	}

	public function display() {
	}

	public function sanitize( $input ) {
	}

}

## 3-register.php
<?php

public function register() {

	register_setting(
		'acme_company_group',		// Group of options
		'acme_company',     	        // Name of options
		array( $this, 'sanitize' )	// Sanitization function
	);

	add_settings_section(
		'acme-company',			// ID of the settings section
		'Company',  			// Title of the section
		'',
		'acme-company-page'		// ID of the page
	);

	add_settings_field(
		'acme-company-name',		// The ID of the settings field
		'Name',				// The name of the field of setting(s)
		array( $this, 'display' ),
		'acme-company-page',		// ID of the page on which to display these fields
		'acme-company'			// The ID of the setting section
	);

}

## 4-display-front-end.php
<?php
/**
 * Displays the UI for editing information with the Acme Company Dashboard.
 *
 * @since      1.0.0
 *
 * @subpackage @TODO
 * @package    Acme_Company
 *
 */
?>

<div class="wrap">

	<h2>Acme Company</h2>

	<?php settings_errors(); ?>

	<form method="post" action="options.php">
		<?php
			settings_fields( 'acme_company_group' );
			do_settings_sections( 'acme-company-page' );
			submit_button();
		?>
	</form>

</div><!-- .wrap -->

## 5-sanitize.php
<?php

public function sanitize( $input ) {

	// The array in which the new, sanitized input will go
	$new_input = array();

	// Read the company name from the array of options
	$val = $input['name'];

	// Sanitize the information
	$val = strip_tags( stripslashes( $val ) );
	$new_input['name'] = sanitize_text_field( $val );

	return $new_input;

}

## 6-acme-company-dashboard.php
<?php

class Acme_Company_Dashboard {

	protected $views;

	public function __construct() {
		$this->views = trailingslashit( plugin_dir_path( dirname( __FILE__ ) ) . 'views' );
	}

	public function run() {

		add_action( 'admin_menu', array( $this, 'add_menu_items' ) );
		$this->create_settings();

	}

	public function add_menu_items() {

		add_submenu_page(
			'tools.php',
			'Acme Company',
			'Add New Company',
			'edit_posts',
			'add_new_company',
			array( $this, 'display_acme_company' )
		);

	}

	public function display_acme_company() {
		include_once $this->views . '4-display-front-end.php';
	}

	private function create_settings() {

		$name = new Acme_Company_Name();
		$name->run();

	}

}

## 7-extending-the-dashboard.php
<?php

class Acme_Company_Name extends Acme_Company_Dashboard implements Acme_Setting {

}

## 8-display-front-end.php
<?php
public function display() {

	// Now grab the options based on what we're looking for
	$company_options = get_option( 'acme_company' );
	$name = isset( $company_options['name'] ) ? $company_options['name'] : '';

	// And display the view
	include_once $this->views . 'partials/company-name.php';

}

## 9-plugin-bootstrap.php
<?php

/**
 * Plugin Name:       Acme Company
 * Plugin URI:        http://tommcfarlin.com/interface-for-the-wordpress-settings-api/
 * Description:       An example for how to use object-oriented principles with the WordPress Settings API.
 * Version:           1.0.0
 * Author:            Tom McFarlin
 * Author URI:        https://tommcfarlin.com
 * License:           GPL-2.0+
 * License URI:       http://www.gnu.org/licenses/gpl-2.0.txt
 */

// If this file is called directly, abort.
if ( ! defined( 'WPINC' ) ) {
	die;
}

// NOTE: These paths will vary based on how you have your files organized. We'll clean these up later.
include_once plugin_dir_path( __FILE__ ) . 'interface-acme-setting.php';
include_once plugin_dir_path( __FILE__ ) . 'class-acme-company-dashboard.php';
include_once plugin_dir_path( __FILE__ ) . 'class-acme-company-name.php';

/**
 * Begins execution of the plugin.
 *
 * Since everything within the plugin is registered via hooks,
 * then kicking off the plugin from this point in the file does
 * not affect the page life cycle.
 *
 * @since    1.0.0
 */
function run_acme_company() {

	$plugin = new Acme_Company_Dashboard();
	$plugin->run();

}
run_acme_company();