Class not found when extended

Question

I have a class MyClass that works fine. When I create an instance using $obj = new MyClass() works like a charm. The problem is, if I extend this class MyClass extends MyExtends, it gives me an error: class MyClass not found.

Because the devil is in the details, here are some:

1) MyClass instance is created in the same file (called MyClass.php).

$obj = new MyClass();
class MyClass extends MyExtends{
}

2) The creation of obj is called using ajax

if($_POST['myAjaxFlag']){
    $obj = new MyClass();
}

3) The ajax call returns as success, but if I print the data returned, I get that class not found error php message.

Where are you defining `MyExtends`? Can you post the exact error message you're getting? — Reinstate Monica -- notmaynard, Oct 21 '13 at 21:49
client-side AJAX uses http status codes to determine success/failure. As long as the PHP side of things returns a 200, Javascript will assume success, even if the actual "success" was a total failure. — Marc B, Oct 21 '13 at 21:50
@iamnotmaynard MyExtends is defined in another file. I include this file at the beginning. — kunde, Oct 21 '13 at 21:56
@TheWolf yes. I elaborated those 2 points separated, but is the same file. The if statment surround the instantiation, and the the class is declared. — kunde, Oct 21 '13 at 21:57
Let's see the MyExtends declaration, and your require statement. Then we'll all be able to play with it ourselves. — sdanzig, Oct 21 '13 at 22:07

score 5 · Accepted Answer · answered Oct 21 '13 at 21:51

5

This is because you declare the class "MyClass" after your initialisation

obj = new MyClass();
class MyClass extends MyExtends{

}

Corrected:

class MyClass extends MyExtends{
}
obj = new MyClass();

Should work then ;)

answered Oct 21 '13 at 21:51

demonking

2,584
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Thank you! I really don't know why this works, but it does. If I don't extend MyClass, it works even if it's before the class declaration. Edit: I saw your response before your correction, and I assumed you wanted to change the order (without the first $obj = new MyClass();) – kunde Oct 21 '13 at 21:59
Yes, you are right, i have corrected my formatting , because it only one Codeblock so i have split in two . But Nice that it works – demonking Oct 22 '13 at 15:19

score 1 · Answer 2 · answered Oct 21 '13 at 21:54

1

Order matters:

<?php
    class Base
    {
        protected function sayHello()
        {
            echo("Base hello\n");
        }
    }

    class Child extends Base
    {
        public function sayHello()
        {
            parent::sayHello();

            echo("Child hello\n");
        }
    }

    $obj = new Child();
    $obj->sayHello();    

?>

Base hello

Child hello

answered Oct 21 '13 at 21:54

Josh

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MyExtends class is declared before MyClass declaration (using `require` at the top). – kunde Oct 21 '13 at 22:04

score 0 · Answer 3 · answered Oct 21 '13 at 21:52

0

You need to define the class before you can use it. So the "new" should come after the class MyClass definition.

Also MyExtends needs to be defined before you can extend it... either beforehand in the same file, or via a "require" statement.

answered Oct 21 '13 at 21:52

sdanzig

4,510
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I require the file where MyExtends is declared at the beginning, but still doesn't works. – kunde Oct 21 '13 at 22:00

Class not found when extended

3 Answers3