Triggering event only on a change of variable output - swift

Question

I have created the following coin toss program which also triggers an audio file with each coin toss every second. I'd like to know how to change this so that the audio only triggers when the result changes from a heads to a tails or vice versa. Not every second as it is now. Any help is greatly appreciated.
import UIKit
import AVFoundation
class ViewController: UIViewController {
var times: Timer!
var timer: Timer!
var coinFlip : Int = 0
var coinResult : String = ""
var audioPlayer : AVAudioPlayer!
let soundArray = ["note1", "note7"]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
times = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(fiftyFifty), userInfo: nil, repeats: true)
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(result), userInfo: nil, repeats: true)
result()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func fiftyFifty() -> Int {
coinFlip = Int(arc4random_uniform(2))
return coinFlip
}
func result() -> String {
if coinFlip == 1 {
coinResult = "Heads"
print("Heads")
playSound(soundFileName: soundArray[0])
}
else {
coinResult = "Tails"
print("Tails")
playSound(soundFileName: soundArray[1])
}
}
func playSound(soundFileName : String) {
let soundURL = Bundle.main.url(forResource: soundFileName, withExtension: "wav")
do {
audioPlayer = try AVAudioPlayer(contentsOf: soundURL!)
}
catch {
print(error)
}
audioPlayer.play()
}
}
I've now changed it to add a new variable output from result(), coinResult. Not sure if this helps but hopefully might.

Answer 1

If I understood well, when the coin flips, you want to play a song, in this case you can simply change your coinFlip declaration to that:
var coinFlip : Int = 0 {
didSet {
result()
}
}
didSet is a property observer that observes and respond to changes in property's value.
didSet is called immediately after the new value is stored.
You can read more about property observers in Apple's documentation.
EDIT: Your code will be like this:
import UIKit
import AVFoundation
class ViewController: UIViewController {
var times: Timer!
var timer: Timer!
// Change this
var coinFlip : Int = 0 {
didSet {
result()
}
}
var audioPlayer : AVAudioPlayer!
let soundArray = ["note1", "note7"]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
times = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(fiftyFifty), userInfo: nil, repeats: true)
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(result), userInfo: nil, repeats: true)
result()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func fiftyFifty() -> Int {
coinFlip = Int(arc4random_uniform(2))
return coinFlip
}
func result() {
if coinFlip == 1 {
print("Heads")
playSound(soundFileName: soundArray[0])
}
else {
print("Tails")
playSound(soundFileName: soundArray[1])
}
}
func playSound(soundFileName : String) {
let soundURL = Bundle.main.url(forResource: soundFileName, withExtension: "wav")
do {
audioPlayer = try AVAudioPlayer(contentsOf: soundURL!)
}
catch {
print(error)
}
audioPlayer.play()
}
}