ios - Insert counter enemies killed -

i'm developing simple 2d play , implement counter every enemy killed , keep displayed on display until game over.

how this? i'm using xcode 7.3.1

my enemies code :

func frecciaincollisioneconnemico(freccia:skspritenode, nemico:skspritenode) {     print("freccia ha colpito un nemico")     freccia.removefromparent()     nemico.removefromparent()      nemicidistrutti += 1     print("hai distrutto \(nemicidistrutti) nemici")      if (nemicidistrutti >= 20) {         let rivela = sktransition.fliphorizontalwithduration(0.5)         let gameoverscene = gameoverscene(size: self.size, vinto: true)         self.view?.presentscene(gameoverscene, transition: rivela)     } } 

you should able answer question easy.

create label

class gamescene: skscene {      let enemieskilledlabel = sklabelnode(fontnamed: "helveticaneue")      override func didmovetoview(view: skview) {         loadenemieskilledlabel()       }      private func loadenemieskilledlabel() {         enemieskilledlabel.position = ...         enemieskilledlabel.text = "0"         ...         addchild(enemieskilledlabel)     } } 

than in death function update text.

 ...  nemicidistrutti += 1   enemieskilledlabel.text = "\(nemicidistrutti)" // update text 

this called string interpolation, can read more here

https://developer.apple.com/library/ios/documentation/swift/conceptual/swift_programming_language/stringsandcharacters.html

as tip should change collision method take in optionals. there case 1 collision calls multiple contacts because multiple body parts collided. code not taking account , therefore crash if frecciaincollisioneconnemico called multiple times in fast succession.

change this

func frecciaincollisioneconnemico(freccia: skspritenode?, nemico: skspritenode?) {      guard let freccia = freccia, nemico = nemico else { return }      freccia.removefromparent()     nemico.removefromparent()     ... } 

lastly recommend try write code in english only.

hope helps