WordPress Options, Simplified

settings.php

class option{
	public function __construct($ID,$title,$object,$callback = null,$page = null,$section = null,$prefix = 'your_prefix_'){
		$this->ID = $prefix.$ID;
		$this->title = $title;
		$this->callback = ($callback == null) ? array($object,$this->ID.'_callback') : array($object,$callback);
		$this->page = ($page == null) ? 'eav-settings-admin' : $page;
		$this->section = ($section == null) ? 'eav_options_id' : $section;
	}
}

class eavSettings{
  /**
   * Holds the values to be used in the fields callbacks
   */
  private $options;

  /**
   * Start up
   */
  public function __construct(){
    add_action('admin_menu', array($this, 'add_plugin_page'));
    add_action('admin_init', array($this, 'page_init'));
		$this->options = array(
			new option('option_id','Option Description',$this),
		);
  }

  /**
   * Add options page
   */
  public function add_plugin_page(){
    // This page will be under "Settings"
    add_options_page(
      'Settings Admin', 
      'Easy Age Verifier', 
      'manage_options', 
      'easy-age-verifier-settings', 
      array( $this, 'create_admin_page' )
    );
  }

  /**
   * Options page callback
   */
  public function create_admin_page(){
    // Set class property
    $this->options = get_option( 'eav_options' );
    ?>
    <h2>Options Title</h2>           
      <div class="wrapper">
        <form method="post" action="options.php">
        <?php
          // This prints out all hidden setting fields
          settings_fields( 'eav_options_group' );   
          do_settings_sections( 'eav-settings-admin' );
          submit_button(); 
        ?>
        </form>
      <div class="eav-admin-sidebar">
        <?php do_action('eav_settings_sidebar');?>
      </div>
    </div>
    <?php
  }

  /**
   * Register and add settings
   */
  public function page_init(){        
    register_setting(
      'eav_options_group', // Option group
      'eav_options' // Option name
    );
		
    add_settings_section(
      'eav_options_id', // ID
      'Easy Age Verifier Settings', // Title
      array( $this, 'print_section_info' ), // Callback
      'eav-settings-admin' // Page
    ); 
		
		//Loop through and build the options
		foreach($this->options as $option){
			add_settings_field(
				$option->ID,
				$option->title,
				$option->callback,
				$option->page,
				$option->section 
			);      
		}
  }

  /** 
   * Print the Section text
   */
  public function print_section_info(){
    print 'Enter your settings below:';
  }

  /** 
   * Get the settings option array and print one of its values
   */
  public function callback_example(){
    printf(
      '<input type="number" id="eav_minimum_age" name="eav_options[eav_minimum_age]" value="%s" />',
      $this->options['eav_minimum_age'] != '' && $this->options['eav_minimum_age'] != 0 ? esc_attr( $this->options['eav_minimum_age']) : apply_filters('eav_default_age',21)
    );
  }

}

if(is_admin()){
  $eav_settings = new settings();
}