Question

I’m trying to create a global context variable in one of my libraries, but can’t seem to figure out how to make the variable stick. Below is a sample of my code:

class test{
    function tester(){
        echo context::getContext();
        echo '<br />';
        context::setContext(2);
        echo context::getContext();
        echo '<br />';
        new test2();
    }
}
class test2{
    public function __construct(){
        echo context::getContext();
    }
}
class context{
    protected static $contextNum = 0;
    public function getContext(){
        return isset($this->contextNum) ? $this->contextNum : 0;
    }
    public function setContext($num){
        $this->contextNum = $num;
    }
}

This ends up echoing:

0
2
0

How can I make it so that it echoes out?

0
2
2

Answer 1

Change

$this->contextNum = $num;
// and
return isset($this->contextNum) ? $this->contextNum : 0;

to

self::$contextNum = $num;
// and
return isset(self::$contextNum) ? self::$contextNum : 0;

Use static modifiers for methods setContext() and getContext()

Also I would advise you to add throw new Exception('Can\'t create instance of this class') to __construct() method of context.