Fixing PHP Fatal Error: Call to Undefined Method (3 Solutions)

Overview

PHP Fatal error: Call to undefined method is an error that PHP developers may encounter at some point. It occurs when you try to call a method on an object or class that does not have the method defined. This article will cover the reasons for this error and provide several solutions to fix it.

Common Causes

The error can be caused by a variety of scenarios:

• Typographical errors in the method name.
• Incorrect class instantiation.
• Accessing methods that are not visible due to their private or protected visibility.
• Using the incorrect object context.
• Calling a method that doesn’t exist in the class’s inheritance chain.

Understanding the Error Message

The error message usually provides the name of the undefined method and the class or the object that is trying to call it. It can help in pinpointing the exact place in the code where the issue is.

3 Solutions to Resolve the Error

Check for Typographical Errors

Commonly, the error is caused by simple misspellings in the method name. Check the method name you are trying to use against the definition in the class.

• Step 1: Find where the method is being called in your code.
• Step 2: Check the spelling and case of the method call.
• Step 3: Ensure it matches the method name in the class definition, considering that PHP is case-sensitive.

Example:

// Example: Typographical error in method call

class MyClass {
    public function myMethod() {
        return 'Method Called';
    }
}

$myObject = new MyClass();
// wrong method call
echo $myObject->myMthod(); // Fatal error: Call to undefined method

// corrected method call
echo $myObject->myMethod(); // Output: Method Called

As you can see from the example, correcting the spelling mistake resolves the error.

Verify Class Instantiation

This error might occur if you are trying to call a method on an object that is not an instance of the expected class.

• Step 1: Confirm the class where the method is defined.
• Step 2: Check your object instantiation and ensure that it creates an instance of the correct class.
• Step 3: Modify the instantiation if necessary to reference the proper class.

Example:

// Example: Incorrect class instantiation

class A {
    public function methodFromA() {
        return 'From A';
    }
}

class B {}

// Attempting to instantiate class B instead of A
$bObject = new B();
echo $bObject->methodFromA(); // Fatal error: Call to undefined method

// Corrected class instantiation
$aObject = new A();
echo $aObject->methodFromA(); // Output: From A

Correct object instantiation is essential for method calls to succeed.

Check Method Visibility

If a method is defined with private or protected visibility, it cannot be accessed from outside the class.

• Step 1: Identify the visibility of the method by checking its definition in the class.
• Step 2: If the method is private or protected, you will need to either change its visibility to public or access it through a public method.
• Step 3: Refactor your code to access the method appropriately based on its visibility constraints.

Example:

// Example: Method visibility issue

class User {
    private function getPasswordHash() {
        return 'hashed_password';
    }
}

$user = new User();
echo $user->getPasswordHash(); // Fatal error: Call to undefined method

// Another class with public accessor

class User {
    private function getPasswordHash() {
        return 'hashed_password';
    }

    public function checkPassword($input) {
        return $input === $this->getPasswordHash();
    }
}

$user = new User();
echo $user->checkPassword('test'); // Output: false

In the new User class implementation, the private method is accessed through a public method of the class, adhering to the principle of encapsulation.