Cannot create subclass of SKSpriteNode

Question

Trying to subclass SKSpriteNode so make my game code cleaner, and I'm obviously not understanding something. Here's a very simple example: I create a new Swift file called Alien.swift with the following contents:

import SpriteKit

class Alien: SKSpriteNode {

}

In my game, I do:

    let alienSprite: Alien = Alien()
    print("It's an \(alienSprite)")

and I get:

It's an (SKSpriteNode) name:'(null)...'

Even Xcode says it's an 'aliensSprite':

Why, at run-time, is it not printing that it's an 'alienSprite'?

Edit: incorporating one of my comments here - I'm actually picking up the sprite from my .sks file, where I placed it with the scene editor and set its custom class. I try to pick it up with:

let alien = childNodeWithName("alien") as! alienSprite 

but I get the error:

Cannot cast SKSpriteNode to alientSprite

Answer 1

Take notice to the state of your scene file. If you see it shaded, this means it has not saved yet. If you compile your code while still in the scene editor, the save will not happen, so be sure to hit cmd + s to save prior to compiling.

Now in case people are trying to figure out why class names are not saving, make sure you hit ENTER or leave the text field and go to another textfield to ensure that the class name saves, otherwise it will revert back to an older state.

Answer 2

You are not using the name of the variable

When you declare

 let alienSprite: Alien = Alien()

You are basically creating an empty SKSpriteNode. This means when you do the string interpolation, you are printing the actual SKSpriteNode and its properties.

To fix this, you have two options.

Original

1. Print the type of alienSprite:

   print("It's an \(type(of: alienSprite))")
   

2. Set the name of the Alien and print that:

   alienSprite.name = "Alien"
   print("It's an \(alienSprite.name)")
   

10/25/16

If you want something like @Knight0fDragon, you can do the following:

print("It's an \(type(of: alienSprite)) \(alienSprite)")

Which is basically an add on the my original answer.

Answer 3

When you print an object, as in print("It's an \(alienSprite)"), you just ask to see its description property. By default for an SKNode this property just prints the name property of the object, as you didn't redefined this behavior you get the message (SKSpriteNode) name: null. If you want to redefine it then change the description in your new class to something more convenient, something like this should work:

class Alien : SKSpriteNode {
    override var description: String {
        return "\(String(describing: type(of:self)))"
    }
}

Remind that you also have a similar debugDescription to control what is printed by the debugger.