Unable to initialized a class that subclasses SKShapeNode, specifically (rectOf: CGSize)

Question

Created Jul ’20

Replies 8

Boosts 0

Views 1.8k

Participants 3

Am trying to subclass SKShapeNode yet it never works. Specifically the SKShapeNode(rectOf: CGSize).

Trying to use init(), super.init, and sometimes the compiler tells me to use the designated initializer, which I cannot find to save my life. Am using Xcode 11 and Swift 5.

Here is a sample of one of my declaration attempts and my call. The self element in the call is from the background pic. It works if I create an SKShapeNode directly using the same parameters. But would like to subclass this so I can add custom methods and properties.

I've scoured the internet and so many other forums. Not one reply. I'm desperate at this point.

Thank you

p.s. I apologize this is a repost. But I only realized too late that I used the wrong tags.

In this sample code I removed all the part that fill color, and position, set the zPosition, etc. because it all works if I do it straight from my GameScene, without using a custom SubClassed attempt.

Code Block class PegBase : SKShapeNode {		
init(rectOfPegBase: CGSize) {
		    super.init()	    	
			self.fillColor = SKColor.red		   
 			self.strokeColor = SKColor.red	
			self.Position = 0			
}   			
required init?(coder aDecoder: NSCoder) {       		fatalError("init(coder:) has not been implemented")   		 
}}
let childP = PegBase(rectOfPegBase: CGSize(width: 		self.size.width * 0.8, height: self.size.height * 0.2))
self.addChild(childP)

Boost

Answer 1

Claude31 OP

Jul ’20

Where do you run this code ? In a playground ?
Where do you call lines 12 and 14 ?

When testing, I found several problems:

line 6: Position is not defined. Where did you declare it ?
line 12: self element in the call is from the background pic: please show real complete code, that will be easier.

So, show the real code
Tell what you expect
Tell what you get and precise error messages.

0

Answer 2

OOPer OP

Jul ’20

First of all, you should better read this section of the Swift Book.

Class Inheritance and Initialization

Some points in your case:

In SKShapeNode, init(rectOf:) is a convenience initializer
To call a convenience initializer in your own initializer, the convenience initializer needs to be inherited and your own initializer needs to be another convenience initializer
To inherit convenience initializers, you need to [1] inherit all the designated initializers or [2] define (override) all the designated initializers
... (You should better read all other parts of the section carefully.)

Thus, conclusion.

Code Block class PegBase : SKShapeNode {
		
		//To use `init(rectOf:)`, your own init needs to be a convenience initializer
		convenience init(rectOfPegBase size: CGSize) {
				//Call `self.init(rectOf:)`, which needs to be inherited from super class
				self.init(rectOf: size)
				self.fillColor = SKColor.red
				self.strokeColor = SKColor.red
				self.position = .zero
		}
		
		//
		//To inherit `init(rectOf:)`, you need to override all the designated initializers...
		//
		
		override init() {
				super.init()
		}
		
		required init?(coder aDecoder: NSCoder) {
				fatalError("init(coder:) has not been implemented")
		}
		
}

Or you can write something like this:

Code Block class PegBase : SKShapeNode {
		
		//To use `init(rectOf:)`, your own init needs to be a convenience initializer
		convenience init(rectOfPegBase size: CGSize) {
				//Call `self.init(rectOf:)`, which needs to be inherited from super class
				self.init(rectOf: size)
				self.fillColor = SKColor.red
				self.strokeColor = SKColor.red
				self.position = .zero
		}
		
		//
		//Or you need to inherit all the designated initializers, by NOT defining any designated initializers
		//
		
}

0

Answer 3

SergioDCQ OP

Jul ’20

Well below is as close as I could get to your code. It compiles, but at runtime I get an

Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
error, which I assume is because the object never gets created.

Thanks for your reply and I promise to start reading that section, but with me being new at Swift, it might take me a while. So any obvious errors you could point out would be greatly apperciated.

Thanks again

Code Block /*  GameScene.swift
*/
import SpriteKit
import GameplayKit
class GameScene: SKScene, SKPhysicsContactDelegate
{
    var pegBaseBoard : PegBaseBoard?
    override func didMove(to view: SKView) {
    let background = SKSpriteNode(imageNamed: "background")
	background.size = self.size
    background.position = CGPoint(x: self.size.width/2, y: self.size.height/2)
    background.zPosition = -1
    self.addChild(background)
     pegBaseBoard! = PegBaseBoard.init(rectOfPegBase : CGSize(width: self.size.width * 0.8, height: self.size.height * 0.2))
     self.addChild(pegBaseBoard!)
    }
}

Code Block /*
//  PegBaseBoard.swift
*/
import Foundation
import SpriteKit
class PegBaseBoard : SKShapeNode
{
        convenience init(rectOfPegBase size: CGSize) {
        self.init(rectOf: size)
        self.fillColor = SKColor.red
        self.strokeColor = SKColor.red
        self.position = .zero
 }
    override init() {
        super.init()
    }
    required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
    }
}

0

Answer 4

OOPer OP

Jul ’20

Seems you need to learn one more important thing before reading the article.

You should start a new thread, if your new question is different than the original question.
That is the right manner to use Q&A sites like this.

Please include a link to this thread, when you start a thread for your Unexpectedly found nil issue.

0

Answer 5

SergioDCQ OP

Jul ’20

Forgive my inexperience in Swift, but isn't this a problem with my subclass not initializing. Sure I could start thread for that, but then I would have I wait for it to return anyway, no?

Right now, if I could just make my subclass do the same as SKShapeNode(rectOf: CGSize), I would be happy.

0

Answer 6

OOPer OP

Jul ’20

@SergioDCQ

but isn't this a problem with my subclass not initializing.

Sorry, I was not clear enough in my previous reply. But the answer is NO.

You are using forced unwrapping in a wrong manner and that has nothing to do with initialization of PegBaseBoard.

0

Answer 7

SergioDCQ OP

Jul ’20

Accepted Answer

Ok, the code below works, as I can tell because the pegBaseBoard is filled with red. So if I consider this step one, how do I start passing extra parameters so I can set the fill, and other properties in the subClass file?

i

Code Block mport Foundation
import SpriteKit
class PegBaseBoard : SKShapeNode
{
    	override init() {
        super.init()
   	 	}
   		 required init?(coder aDecoder: NSCoder) {
		fatalError("init(coder:) has not been implemented")
   		 }
}

Code Block import SpriteKit
import GameplayKit
class GameScene: SKScene, SKPhysicsContactDelegate
{
	var pegBaseBoard = PegBaseBoard()
    override func didMove(to view: SKView) {
	let background = SKSpriteNode(imageNamed: "background")
	background.size = self.size
	background.position = CGPoint(x: self.size.width/2, y: self.size.height/2)
	background.zPosition = -1
	self.addChild(background)
	
	pegBaseBoard = PegBaseBoard.init(rectOf : CGSize(width: self.size.width * 0.8, height: self.size.height * 0.2))
	pegBaseBoard.fillColor = SKColor.red
	self.addChild(pegBaseBoard)
  }
}

0

Answer 8

OOPer OP

Jul ’20

Please follow the rule, one thread, one topic.

The issue Unable to initialized a class that subclasses SKShapeNode, specifically (rectOf: CGSize) is SOLVED, no?
You should start a new thread for a new question.

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