Why my contact recogniser doesn't work - swift

Question

I made contact recogniser using physics body, category bit mask and SKPhysics contact. Unfortunately it do not work. Could You help me somehow to find mistake?
This code do not print statement Touched.
Is it because one body is SKSpriteNode and second SKShapeNode? Could we recognise contact between SpriteNode and ShapeNode?
I made all improvements like #giorashc said with SKPhysics body, but in not worked.
import Foundation
import SpriteKit
import GameplayKit
import UIKit
var TouchLevel3BadgeChecker = 0
enum BodyType:UInt32{
case TheCircle = 1
case TheEightBack = 2
}
class TouchLevel3SceneClass: SKScene, SKPhysicsContactDelegate{
var Eight = SKSpriteNode(imageNamed: "8.png")
var EightBack = SKSpriteNode(imageNamed: "8Back.png")
var counter : Int = 0;
override func didMove(to view: SKView) {
self.physicsWorld.contactDelegate = self
Eight.position = CGPoint(x: 0, y: -50)
Eight.name = "Eight"
addChild(Eight)
EightBack.position = CGPoint(x: 0, y: -50)
EightBack.name = "EightBack"
EightBack.zPosition = 2
EightBack.physicsBody? = SKPhysicsBody(texture: EightBack.texture!,
size: EightBack.texture!.size())
EightBack.physicsBody?.usesPreciseCollisionDetection = true
EightBack.physicsBody?.isDynamic = true
EightBack.physicsBody?.affectedByGravity = false
EightBack.physicsBody?.categoryBitMask = BodyType.TheEightBack.rawValue
addChild(EightBack)
Circle.position = CGPoint(x: 0, y: -25)
Circle.zPosition = 2;
Circle.fillColor = SKColor.black;
Circle.name = "Circle"
Circle.physicsBody? = SKPhysicsBody(circleOfRadius: 30)
Circle.physicsBody?.usesPreciseCollisionDetection = true
Circle.physicsBody?.isDynamic = true
Circle.physicsBody?.affectedByGravity = false
Circle.physicsBody?.categoryBitMask = BodyType.TheCircle.rawValue
Circle.physicsBody?.collisionBitMask = BodyType.TheEightBack.rawValue
Circle.physicsBody?.contactTestBitMask = BodyType.TheEightBack.rawValue
addChild(Circle)
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches{
let location = t.location(in: self);
if atPoint(location).name == "Circle"{
Circle.position.x = location.x
Circle.position.y = location.y
}
}
}
func didBegin(_ contact: SKPhysicsContact) {
if contact.bodyA.categoryBitMask == BodyType.TheCircle.rawValue && contact.bodyB.categoryBitMask == BodyType.TheEightBack.rawValue{
print("Touched")
} else if contact.bodyB.categoryBitMask == BodyType.TheCircle.rawValue && contact.bodyA.categoryBitMask == BodyType.TheEightBack.rawValue{
print("Touched")
}
}
}

Answer 1

You are not creating the physicsBody property. Since its optional and nil setting its properties won't do anything.
create the physicsBody property with:
EightBack.physicsBody = SKPhysicsBody(...);
Circle.physicsBody = SKPhysicsBody(...);
check the example in this link: https://developer.apple.com/documentation/spritekit/skphysicsbody