This is a very simple sample plugin for Admin Page Framework v2 that adds form elements.

admin-page-framework-demo-form.php

<?php
/* 
  Plugin Name: Admin Page Framework - Sample Form Elements
	Plugin URI: http://en.michaeluno.jp/admin-page-framework
	Description: Demonstrates adding a form elements for Admin Page Framework v2.0.0 or above.
	Author: Michael Uno
	Author URI: http://michaeluno.jp
	Version: 0.0.1
	Requirements: PHP 5.2.4 or above, WordPress 3.2 or above, Admin Page Framework 2.0.0 or above.
*/ 

if ( ! class_exists( 'AdminPageFramework' ) )
	include_once( dirname( __FILE__ ) . '/class/admin-page-framework.php' );
    
class APF_Sample_Form_Elements extends AdminPageFramework {

	public function setUp() {
		
		$this->setRootMenuPage( 'APF Form' );   // specifies to which parent menu to belong.
		
		$this->addSubMenuItems(
			array(
				'strPageTitle' => 'Form Fields',
				'strPageSlug' => 'apf_form_fields',
				'numOrder' => 1,
			)
		);
		
		$this->addSettingSections(
			array(
				'strSectionID'		=> 'text_fields',
				'strPageSlug'		=> 'apf_form_fields',
				'strTitle'			=> 'Text Fields',
				'strDescription'	=> 'These are text type fields.',
				'numOrder'			=> 10,
			),	
			array(
				'strSectionID'		=> 'selectors',
				'strPageSlug'		=> 'apf_form_fields',
				'strTitle'			=> 'Selectors',
			)
		);
		$this->addSettingFields(
			array(	// Single text field
				'strFieldID' => 'text',
				'strSectionID' => 'text_fields',
				'strTitle' => 'Text',
				'strDescription' => 'Type something here.',	
				'strType' => 'text',
				'numOrder' => 1,
				'vDefault' => 123456,
				'vSize' => 40,
			),
			array(	// Text Area
				'strFieldID' => 'textarea',
				'strSectionID' => 'text_fields',
				'strTitle' => 'Single Text Area',
				'strDescription' => 'Type a text string here.',
				'strType' => 'textarea',
				'vDefault' => 'Hello World! This is set as the default string.',
				'vRows' => 6,
				'vCols' => 80,
			),	
			array(	// Single Dropdown List
				'strFieldID' => 'select',
				'strSectionID' => 'selectors',
				'strTitle' => 'Dropdown List',
				'strDescription' => 'This is a drop down list.',
				'strType' => 'select',
				'vDefault' => 2,
				'vLabel' => array( 'red', 'blue', 'yellow', 'orange' )
			),	
			array( // Submit button 
				'strFieldID' => 'submit_button',
				'strSectionID' => 'selectors',
				'strType' => 'submit',
				'vLabel' => __( 'Save Changes' ),
			)			
		);			
	}
}
if ( is_admin() )
	new APF_Sample_Form_Elements;