Changeable Image - xcode

Question

Ghost = SKSpriteNode(imageNamed: "Ghost1")
Ghost.size = CGSize(width: 50, height: 50)
Ghost.position = CGPoint(x: self.frame.width / 2 - Ghost.frame.width, y: self.frame.height / 2)
Ghost.physicsBody = SKPhysicsBody(circleOfRadius: Ghost.frame.height / 1.4)
Ghost.physicsBody?.categoryBitMask = PhysicsCatagory.Ghost
Ghost.physicsBody?.collisionBitMask = PhysicsCatagory.Ground | PhysicsCatagory.Wall
Ghost.physicsBody?.contactTestBitMask = PhysicsCatagory.Ground | PhysicsCatagory.Wall | PhysicsCatagory.Score
Ghost.physicsBody?.affectedByGravity = false
Ghost.physicsBody?.isDynamic = true
Ghost.zPosition = 2
self.addChild(Ghost)
On my app i have an object that moves around on the screen and it name is "ghost". I am not sure how to set up a button that would change the code to say
Ghost = SKSpriteNode(imageNamed: "Ghost2")
instead of
Ghost = SKSpriteNode(imageNamed: "Ghost1")

Answer 1

To change the image for an SKSpriteNode you assign a different texture:
Ghost.texture = SKTexture(imageNamed:"Ghost2")
Note: You should use lower case letters for variable names to distinquish them from class names.
An example implementation that includes a Button and your Ghost would be like below with a red button created in the top right corner. See that the declaration of the button and the ghost now occurs outside of didMoveToView, so that these variables can be referenced later, when the user taps the screen.
class ButtonGhostScene: SKScene {
var button: SKNode! = nil
var ghost: SKSpriteNode! = nil
override func didMove(to view: SKView) {
button = SKSpriteNode(color: SKColor.redColor(), size: CGSize(width: 100, height: 44))
button.position = CGPoint(x:self.size.width, y:self.size.height)
ghost = SKSpriteNode(imageNamed: "Ghost1")
ghost.size = CGSize(width: 50, height: 50)
ghost.position = CGPoint(x: self.frame.width / 2 - Ghost.frame.width, y: self.frame.height / 2)
ghost.physicsBody = SKPhysicsBody(circleOfRadius: Ghost.frame.height / 1.4)
ghost.physicsBody?.categoryBitMask = PhysicsCatagory.Ghost
ghost.physicsBody?.collisionBitMask = PhysicsCatagory.Ground | PhysicsCatagory.Wall
ghost.physicsBody?.contactTestBitMask = PhysicsCatagory.Ground | PhysicsCatagory.Wall | PhysicsCatagory.Score
ghost.physicsBody?.affectedByGravity = false
ghost.physicsBody?.isDynamic = true
ghost.zPosition = 2
self.addChild(ghost)
self.addChild(button)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
// Loop over all the touches in this event
for touch: AnyObject in touches {
// Get the location of the touch in this scene
let location = touch.location(in: self)
// Check if the location of the touch is within the button's bounds
if button.containsPoint(location) {
ghost.texture = SKTexture(imageNamed:"Ghost2")
}
}
}
}
When the user taps the screen, touchesBegan is executed and a check is made to see if the users tap is on the button.