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PHP Object-Oriented PHP Basics (Retired) Inheritance, Interfaces, and Exceptions Managing Exceptions

Aman Kumar
Aman Kumar
10,444 Points
Posted by Aman Kumar
Aman Kumar
10,444 Points

How can I access the static method "getMaker()"?

Sorry to ask question here about the last topic. Actually, i got it in the quiz

Right answer was static::getMaker()

But in one of my example when i tried the same syntax, it generated an error

Below is the code i tried

 <?php
    class Animal
    {

        public static $owner = 'Hayden';

        public $name;
        public $color;

        public function __construct($name, $color)
        {
            $this->name = $name;
            $this->color = $color;
        }

        public function getInfo()
        {
            return $this->name . $this->color;
        }

        public function getOwner()
        {
            return self::$owner;
        }

        public static function getOwnerName()
        {
            return self::$owner;
        }
    }

    class Dog extends Animal
    {
        public $breed;

        public function __construct($name, $color, $breed)
        {
            parent::__construct($name, $color);
            $this->breed = $breed;
        }

        public function getInfo()
        {
            return 'Name: ' . $this->name . '<br/>Color: ' . $this->color . '<br/>Breed: ' .  $this->breed;
        }
    }

?>

then i tried

    echo static::getOwnerName();

and i got an error

Fatal error: Cannot access static:: when no class scope is active in /Applications/XAMPP/xamppfiles/htdocs/treehouse/oop.php on line 118

ignore the path specified

Can anyone please explain me about the the error in a bit detail. Thank You.

Arbee Jacob Pagalilauan
Arbee Jacob Pagalilauan
7,483 Points
Arbee Jacob Pagalilauan
Arbee Jacob Pagalilauan
7,483 Points

I was also confused on the same question. I tested both: "$this->getMaker();" and "static::getMaker();" and they seemed to work on the following code with no errors encountered on my end.

Code:

<?php

class Product {
  public static $manufacturer = "Bart Taylor";

  public $name = 'default_name';
  public $price = 0;
  public $desc = 'default description';

  function __construct($name, $price, $desc){
    $this->name = $name;
    $this->price = $price;
    $this->desc = $desc;
  }

  public function getInfo(){
    echo "Product Name: " . $this->name . "</br>";

    //question in quiz
    $this->getMaker();
    static::getMaker();
  }

  public static function getMaker(){
    echo self::$manufacturer . "</br>";
  }

}

$shirt = new Product('Space Juice T-shirt', 20 , 'Awesome Grey T-shirt');
$shirt->getInfo();

Output:

  • Product Name: Space Juice T-shirt
  • Bart Taylor
  • Bart Taylor

Please clarify. :)

3 Answers

Chris McKirgan
Chris McKirgan
5,666 Points
Chris McKirgan
Chris McKirgan
5,666 Points

To call a function statically, you simply need to call the static function using the format:

class::staticfunction();

Where 'class' is the name of your class ('Animal') and 'staticfunction' is your desired function ('Animal'). E.g.: 

Animal::getOwnerName();

The key is understanding the syntax of what the format of the function definition is. Heres a breakdown using your function as an example

public static function getOwnerName()

Public

This is the scope of your function. This allows it to be access in other classes, or within your own. Options are public, private etc.

static

This allows your function to be called without instantiating your class as an object - you can just use Animal:: getOwnerName(); . Just note that this could mean you can call other functions, nor rely on the class's __constructor() method.

function

This tells PHP that the definition is a function.

getOwnerName

This is the name of your choice for the function.

()

These allow you to put in variable paramets to be accessed as scoped variables within your function. You could, for example do the following: Animal:: getOwnerName('harry');

// ^-- code
public static function getOwnerName($sName) {
     echo $sName; // simply echos your parsed parameter.
}
// code --v
Aman Kumar
Aman Kumar
10,444 Points
Aman Kumar
Aman Kumar
10,444 Points

I asked that, the correct answer to that question in the quiz was static::getInfo() but it is not working in my case. Why ?

Chris McKirgan
Chris McKirgan
5,666 Points
Chris McKirgan
Chris McKirgan
5,666 Points

@amamkr if that is the case, the only possible reason for it is that there is another class called "static" of which you are calling the static function "getInfo". I have seen in quizes that they often fabricate new code to try and abstract the concepts from your own code.

It would be helpful to see the question and options in context - could you share them? I'm confused as you are at this point without it! :o)

Matthew Newman
Matthew Newman
8,741 Points
Matthew Newman
Matthew Newman
8,741 Points

I think that answer to that question is either miss leading of just wrong. But below I compiled three ways to return the value of the $owner property which "Hayden".

Hope this helps.

I tested all three of these examples in workspaces and all work. ENJOY :)

echo Animal::$owner; //Calls the value of $owner property straight from the Animal class PROPERTY

echo Animal::getOwnerName(); //Calls the value of $owner property straight from the Animal class METHOD

$ownerObject = new Animal(); echo $ownerObject->getOwner(); //Calls the value of $owner property from an INSTANCE of the Animal class

Matthew Newman
Matthew Newman
8,741 Points
Matthew Newman
Matthew Newman
8,741 Points

Here is a better formatted version:

<?php echo Animal::$owner . '<br>'; //Calls the value of $owner property straight from the Animal class PROPERTY

echo Animal::getOwnerName() . '<br>'; //Calls the value of $owner property straight from the Animal class METHOD

$ownerObject = new Animal(); echo $ownerObject->getOwner() . '<br>'; //Calls the value of $owner property from an INSTANCE of the Animal class ?>