PHP Classes - Fatal error: Call to undefined method

Question

test.php

class AClass {
    public function __construct()
    {
        echo '<strong style="color:blue;">AClass construct</strong><br>';
    }

    public function call()
    {
        $this->koko();
    }

    private function koko()
    {
        echo 'koko <br>';
    }
}

class BClass extends AClass {

    public function __construct()
    {
        echo '<strong style="color:red;">BClass construct</strong><br>';
        parent::__construct();
    }

    public function momo()
    {
        echo 'momo <br>';
    }
}


$xxx = new AClass(); // Output: AClass contruct ..... (where is BClass echo ?)
$xxx->call(); // Output: koko
$xxx->momo(); // Output: Fatal error: Call to undefined method AClass:momo()

Maybe newbe question but.... What is wrong ?

You haven't declared BClass, $xxx is an instance of AClass. Thus, the method doesn't exist. — MackieeE
– MackieeE, Commented Jan 20, 2014 at 10:37
You are calling the base class while the function you are trying to call is in inherited class Bclass. Try $xxx = new Bclass() — Nouphal.M
– Nouphal.M, Commented Jan 20, 2014 at 10:39
If you are going to use inheritance then be sure to learn how it works. — Sverri M. Olsen
– Sverri M. Olsen, Commented Jan 20, 2014 at 10:39

Philipp · Accepted Answer · 2014-01-20 10:37:36Z

8

You got the wrong direction.. if ClassB extends ClassA, ClassB inherits everything from ClassA and not the other way.. So you have to write the Code as follows:

$xxx = new BClass();
$xxx->call();
$xxx->momo();

answered Jan 20, 2014 at 10:37

Philipp

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3 Comments

NoBugs Over a year ago

Unfortunately the parent method isn't called, for some reason PHP class has to have its own method even if the one it extends has the method - php 5.5.9

Philipp Over a year ago

@NoBugs if you want to call the parent method in an overriden method, you have to do this explicitly with parent::methodName(...)

Gem Over a year ago

@Philipp Guide me, how can i solve the error - Fatal error: Call to undefined method Mage_Catalog_Model_Resource_Product_Flat::loadAllAttributes() in /home/abc/public_html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php on line 435

raj · Accepted Answer · 2014-01-20 10:36:51Z

1

The method (momo) you are trying to access belongs to the child class (BClass) and not to the base class (AClass) and hence the error.

answered Jan 20, 2014 at 10:36

raj

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Comments

Kaushik · Accepted Answer · 2014-01-20 10:40:27Z

$xxx = new BClass();
$xxx->call();
$xxx->momo();

this can call

$aClass = new AClass();
$aClass->call();
// you can't call private method.

if you're not creating the object of class B then you can't call momo()

when you extend a class, the subclass inherits all of the public and protected methods from the parent class. Unless a class overrides those methods, they will retain their original functionality.

Note: Unless autoloading is used, then classes must be defined before they are used. If a class extends another, then the parent class must be declared before the child class structure. This rule applies to classes that inherit other classes and interfaces.

<?php

class foo
{
    public function printItem($string)
    {
        echo 'Foo: ' . $string . PHP_EOL;
    }

    public function printPHP()
    {
        echo 'PHP is great.' . PHP_EOL;
    }
}

class bar extends foo
{
    public function printItem($string)
    {
        echo 'Bar: ' . $string . PHP_EOL;
    }
}

$foo = new foo();
$bar = new bar();
$foo->printItem('baz'); // Output: 'Foo: baz'
$foo->printPHP();       // Output: 'PHP is great' 
$bar->printItem('baz'); // Output: 'Bar: baz'
$bar->printPHP();       // Output: 'PHP is great'

?>

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