尝试访问从另一个类扩展的类中的对象

Question

I'm Trying to access an object in a class extended from another class. But I'm getting the error "Trying to get property of non-object".

This is the code: http://3v4l.org/ZLTWf#v500

why can i not access the $doo->var_2->var ? i works fine with $foo->var_2->var (as it should) but why do i get an error when i extend the class? Is it allowed in PHP? Is there some extra code that will allow me to do that?

I'm even getting an "Undefined variable" error on $doo->$var_3

Answer 1

Problem is here

class TheClass extends SecondClass{
    public $var_3;
    function __construct(){
        $this->var_3 = "Some Text...";
    }
}

You have overwritten the parent constructor so when you instantiate the class the constructor of its parent will not be called since its overwritten.

You can fix it as

class TheClass extends SecondClass{
    public $var_3;
    function __construct(){
        parent::__construct();
        $this->var_3 = "Some Text...";
    }
}