Question

I have a main class and two extended classes:

class Main {
    public $foo;
}

class A extends Main {
  public function setVar()
    {
      $foo = "test"; 
    }
}

class B extends Main {
  public function getVar()
    {
      return $this->foo;
    }
}

$A = new A;
$B = new B;

$A->setVar();

echo "result: ".$B->getVar();

But result ($B->getVar()) stays empty. I am clearly missing something simple here… Besides that, is this the way to go splitting long classes up in relevant subclasses?

Answer 1

Example of using Dependency Injection (DI) to share an instance of Main between to different class instances rather than trying to use inheritence

class Main {
    public $foo;
}

class A {

    protected $main;

  public function setVar($data)
    {
      $this->main->foo = $data;
    }

  public function __construct(Main $main)
    {
      $this->main = $main;
    }
}

class B extends Main {
    protected $main;

  public function getVar()
    {
      return $this->main->foo;
    }

  public function __construct(Main $main)
    {
      $this->main = $main;
    }
}

$M = new Main;
$A = new A($M);
$B = new B($M);

$A->setVar("test");

echo "result: ".$B->getVar();