OOP Problem

trs21219 · 09-17-2007, 04:01 AM

ok ive been trying to figure this out for a while now...ive googled it and looked on oop tutorials and cant figure out whats wrong.

my index file is as follows:

Code:

<?php
require_once('include/System_class.php');
?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<?php $System -> Layout -> setCSS('style_main','v1');?>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title><?php $System -> Configuration -> getSiteTitle();?></title>
</head>
	<body>
		<div align='center'>
			<div class="wrapper">
				<div class="container">
					  <div class="header">
					<?php $System -> Layout -> getHeader();?>
				   
 </div>
					<div class="content">
					<?php $System -> Layout -> getContent();?>
					</div>
				 	<div class="footer">
					<?php $System -> Layout -> getFooter();?>
					</div>
				</div>
			</div>
		</div>
	</body>
</html>

my System_class.php

Code:

<?php
include('include/classes/class_configuration.php');
$System -> Config = new Configuration;

include('include/classes/class_database.php');
$System -> DB = new Database;

include('include/classes/class_games.php');
$System -> Games = new Games;

include('include/classes/class_layout.php');
$System -> Layout = new Layout;

include('include/classes/class_media.php');
$System -> Media = new Media;

include('include/classes/class_security.php');
$System -> Security = new Security;

include('include/classes/class_users.php');
$System -> Users = new Users;

?>

layout class

Code:

<?php

class Layout
{
	// Including Pages for Layout
	function getHeader()
	{
		include('include/layout/header.php');
	}
	function getContent()
	{
		$this -> getMenu();
		$this -> getMemberBar();
		$this -> getContentBody();
	}
	function getFooter()
	{
		include('include/layout/footer.php');
	}
	function getMenu()
	{
		echo "<div class='menu'>";
		include('include/layout/menu.php');
		echo "</div>";
	}
	function getContentBody()
	{
		echo "<div class='contentbody'>";
		include('include/layout/content.php');
		echo "</div>";
	}
	function getMemberBar()
	{
		echo "<div class='memberbar'>";
		echo "memberbar is here";
		echo "</div>";
	}
	//end
	
	//Set the css for each page
	function setCSS($name, $version)
	{
		echo "<link href=\"http://" . $_SERVER['HTTP_HOST'] . "/layout/" . $version . "/" . $name . ".css\" rel=\"stylesheet\" type=\"text/css\">";
	}


}
?>

config class

Code:

<?php

class Configuration
{
	function getSiteTitle()
	{
		if(isset($pagename))
		{
			echo $pagename . " - AlliedDefiance.com";
		}
		else
		{
			echo "AlliedDefiance.com";
		}
	}
	function showSiteName()
	{
		echo "Allied Defiance";
	}
}
?>

and my footer.php

Code:

<p>

All Content &copy; 2007 <a href="http://www.allieddefiance.com"><?php $System -> Config -> showSiteName();?></a><br />

</p>

now the problem is that all the system functions work in the index.php file but when i call them from other files i get the Fatal error: Call to a member function on a non-object error. the files are included so they should inherit the class thats set in the index shouldnt they? could someone please tell me whats happening here and how to fix it? im new at OOP but i know php.

Karl · 09-17-2007, 01:15 PM

Well that error implies that you are trying to call a function of an object that is not a valid object. For instance

$p->my_function();

instead of

$p = new MyObject();
$p->my_function();

At a guess, I would say that the object is being instantiated in index.php (or a file included by index.php) and so therefore that file is working fine. However, in the other files (where you get an error), the error would suggest that you are not initialising an instance of the class, but rather, trying to access a function of a non existent class. I would ensure that the class is instantiated by looking back at index.php and it's included files, then ensuring you do the same on subsequent pages.

Wildhoney · 09-17-2007, 01:24 PM

I see the problem here. As you are including the files in your class itself, you're correct in that it inherits it, but it retains its scope. Therefore, take header.php as our example, because it is being included in the getHeader() function it will be included correctly, but be classed as part of the class.

Thus, in header.php you can still call the functions in your Layout class, but instead of using the object itself that you created when initiating your class, in your example, $System->Layout, it would simply by $this.

Wrong:

PHP Code:


			
<?php echo $System->Config->showSiteName();?>

Right:

PHP Code:


			
<?php echo $this->showSiteName();?>

trs21219 · 09-17-2007, 08:27 PM

so if i just normally include the files in the index.php instead of the class should the class then work?

trs21219 · 09-17-2007, 08:32 PM

ahh yes it does work if i do that... thank you so much for your help wildhoney. i knew it would be something small and stupid but didnt know what it could be.