Settings-API-Helper example

controller.php

<?php

namespace Example\Theme;

class Theme_Options {

	/**
	 * the option key
	 *
	 * @const string
	 */
	const KEY = '_ex_theme_header';

	/**
	 * the group key
	 *
	 * @const string
	 */
	const SECTION = '_ex_theme_header_section';

	/**
	 * settings api object
	 *
	 * @var \Settings_API_Helper
	 */
	public $settings;

	/**
	 * init the settings API
	 *
	 * @wp_hook admin_init
	 * @return void
	 */
	public function init_settings() {

		$this->settings =  new \Settings_API_Helper(
			self::KEY,
			self::SECTION, # use this as identifier to render the fields in the view using do_settings_section()
			__( 'Title', 'ex-theme' ),
			__( 'Caption', 'ex-theme' )
		);
		# Testinput field
		$this->settings->add_text(
			'slug',
			__( 'Label', 'ex-theme' ),
			array(
				'default'         => '',
				'output_callback' => 'esc_attr',
				'class'           => 'large-text',
				'html_after'     => '<p>Various stuff</p>'
			)
		);	
	}
}

view.php

<?php


namespace Example\Theme;

class Theme_Options_Admin_Page {


	/**
	 * the slug of the parent page
	 *
	 * @var string
	 */
	public $parent_slug;

	/**
	 * the title of the page
	 *
	 * @var string
	 */
	public $page_title;

	/**
	 * the title of the menu item
	 *
	 * @var string
	 */
	public $menu_title;

	/**
	 * required capability to view the page
	 *
	 * @var string
	 */
	public $capability;


	/**
	 * the menu slug
	 *
	 * @var string
	 */
	public $menu_slug;


	/**
	 * constructor
	 *
	 * @return Example\Theme\Theme_Options_Admin_Page
	 */
	public function __construct() {

		$this->parent_slug = 'themes.php';
		$this->page_title  = __( 'Theme-Settings', 'ex-theme' );
		$this->menu_title  = __( 'Theme-Settings', 'ex-theme' );
		$this->capability  = 'edit_themes';
		$this->menu_slug   = 'ex_theme_options';
	}

	/**
	 * register the page
	 *
	 * @return void
	 */
	public function register() {

		add_submenu_page(
			$this->parent_slug,
			$this->page_title,
			$this->menu_title,
			$this->capability,
			$this->menu_slug,
			array( $this, 'render_page' )
		);
	}

	/**
	 * the page template
	 *
	 * @return void
	 */
	public function render_page() {

		?>
		<div class="wrap">
			<h2><?php echo $this->page_title;?></h2>
			<div id="poststuff" class="metabox-holder has-right-sidebar">
				<div id="post-body">
					<div id="post-body-content">
						<div id="normal-sortables" class="meta-box-sortables ui-sortable">
							<div class="postbox inside">
								<form method="post" action="options.php">
									<?php
									#displays hidden fields and stuff
									settings_fields( \Example\Theme\Theme_Options::SECTION );
									do_settings_sections( \Example\Theme\Theme_Options::SECTION );
									?>
									<div class="inside">
										<p>
											<input type="submit" class="button-primary" name="submit" value="<?php esc_attr_e( 'Save', 'ex-theme' ); ?>" />
										</p>
									</div>
								</form>
							</div>
						</div>
					</div>
				</div>
			</div>
		</div>
		<?php
	}


}