[RESOLVED] Class VARs

LordZenith

Hey,
I'm writing a web core and i'm in a predicament. I'll try to create an example. I know this example is sloppy, I don't have much time. 4 AM here.

<?php
$core=new core();

class core {
var $PAGE;

...
}

class users extends core {
...
}

class usersonlinesystem extends core {
$query="INSERT ........ VALUES ('$this->PAGE', ....)
}

I've also tried $core->PAGE. I've never worked with VARs in classes I usually just keep them global variables but I need to get more specific so I'm creating it this way.

NogDog

How is $PAGE being populated? If it is done by class core's constructor, you will need to explicitly call that constructor from your sub-classes:

<?php
class core
{
   var $PAGE = '';

   function core()
   {
     $this->PAGE = 'foobar';
   }
}

class usersonlinesystem extends core
{
   function usersonlinesystem()
   {
      parent::core();
   }
}

$test = new usersonlinesystem();
echo $test->PAGE;  // outputs "foobar"

LordZenith

NogDog wrote:
How is $PAGE being populated? If it is done by class core's constructor, you will need to explicitly call that constructor from your sub-classes:
<?php
class core
{
   var $PAGE = '';

   function core()
   {
     $this->PAGE = 'foobar';
   }
}

class usersonlinesystem extends core
{
   function usersonlinesystem()
   {
      parent::core();
   }
}

$test = new usersonlinesystem();
echo $test->PAGE;  // outputs "foobar"

What if it was like this?

<?php

$core=new core();

$core->PAGE = 'foobar';

class core
{
   var $PAGE = '';

}

class usersonlinesystem extends core
{
   function usersonlinesystem()
   {
      parent::core();
   }
}

$test = new usersonlinesystem();
echo $test->PAGE;  // outputs "foobar"

NogDog

No, because then you are setting the value of $PAGE in an object instance of core, not as part of the class definition; so it will not be inherited by any classes which extend it.

LordZenith

So If I declare the variable inside the function inside the class it should be 'accessible' from other classes correct?

LordZenith

Okay, I got that working. But now another problem.

<?php
$core=new core();
$user=new User();
$user->loginCheck();
class core {
var $PAGE;
   function core() {
   $this->PAGE='test';
   }
}
class Users extends core {
var  $USERNAME;
 function loginCheck() {
   ...sql query... $this->USERNAME=$row['USERNAME'];
 }
}
class UsersOnlineSystem extends Users {
  ...sql query... INSERT blah blah VALUES ('$this->USERNAME','$this->PAGE');
}

Shrike

First of all, the reason your code doesn't work is that you are using single quotes in insertOnlineUsers().

Before diving headlong into objects, you should understand what the features such as inheritance should be used for. Inheritance is used to specialise a class.

In your case UsersOnlineSystem does not specialise class Users or class Base. A good litmus test to take is asking yourself 'is class B a type of class A' when considering inheritance. If the answer is no, the best approach is to use composition instead.

class core {
var $PAGE;
   function core() {
   $this->PAGE='test';
   }
} 
class User
{
  var $USERNAME;
  function loginCheck()
  {
    ...sql query... $this->USERNAME=$row['USERNAME'];
  }
}
class UsersOnlineSystem
{
  function insertOnlineUsers( $users, $core )
  {
    ...sql query... INSERT blah blah VALUES ($users->USERNAME,$core->PAGE); 
  }
}
$core  = new Core;
$users = new Users;
$users->loginCheck();
$online = new UsersOnlineSystem;
$online->insertOnlineUsers( $users, $core );

On a sidenote, a class without properties has no business being a class.

LordZenith

Shrike wrote:
On a sidenote, a class without properties has no business being a class.

Yeah, but this was a quick explanation, moving quickly. Got sleepy 🙂. I'll try what you said and reply back later. Thanks

LordZenith

Okay, I've gotten most of what I need, thank you everyone. But I do have one final question. (I hope it's the final question.) Is there anyway I can edit the vars in a class and have them be accessible from another class without them being defined in the constructor.



<?php
$core=new core();
$users=new users();

$core->PAGE='test'; 
class core { 
  var $PAGE='';

}

class users extends core {
 var $USERNAME;

echo $this->USERNAME . ' is on ' . $this->PAGE;

}

?>

(I want to be able to define this outside of the class because this webcore that i'm creating will be just uploaded and I want to be able to easily go into the header of the actual files and say <?php require_once('core.php'); $core->PAGE='test'; ?> )

bradgrafelman

I'm not experienced with OOP, but here's how I managed to get what you're after:

$core=new core(); 
$users=new users($core); 
$users->USERNAME = 'brad';

$core->PAGE='test page'; 
class core { 
  var $PAGE=''; 
} 

class users extends core { 
	var $USERNAME;
	var $core;

function __construct($obj) {
	$this->core = $obj;
}

function test() {
	echo $this->USERNAME . ' is on ' . $this->core->PAGE; 
}
} 

$users->test(); // brad is on test page

EDIT: Here's another way of doing it:

class core { 
	var $PAGE='';

function getPage() {
	return $this->PAGE;
}

function setPage($title) {
	$this->PAGE = $title;
}
} 

class users extends core { 
	var $USERNAME;

function test() {
	echo $this->USERNAME . ' is on ' . parent::getPage(); 
}

function setPage($title) {
	parent::setPage($title);
}
} 

$users=new users(); 

$users->USERNAME = 'brad';
$users->setPage('test page');

$users->test(); // brad is on test page

bradgrafelman

Just thought I'd make a new post, but here's a cleaner way (I'm stupid! :p):

class core { 
	var $PAGE='';
} 

class users extends core { 
	var $USERNAME;

function test() {
	echo $this->USERNAME . ' is on ' . $this->PAGE; 
}
} 

$users=new users(); 

$users->USERNAME = 'brad';
$users->PAGE = 'test page2';

$users->test(); // brad is on test page2

LordZenith

I fixed it!

I'ma go to bed but to keep it simple...


$core=new core();
$users=new users()
$usersonline=new usersonline();
$core->PAGE='test';
$users->USER='Visitor';
$usersonline->Update($core, $users);

class core {
var $PAGE='';
....
}

class users extends core{
var $USERNAME='';
....
}

class usersonline extends core{
     function Update($core, $users) {
     ... INSERT INTO SQL DATABASE $core->PAGE, $users->USERNAME;
    }
}

Done 🙂 Thanks guys. I have a feeling that I'll be back. Hopefully not for the same topic.

bradgrafelman

Don't forget to mark this thread resolved (if it is).