Conditional audio playing using AV Audio Player in Swift - ios

Question

I would like to be able to play audio on pressing a button a maximum of twice. After pressing the button twice it should no longer play audio even when pressed. I have this code currently, but it doesn't work and I am unsure where I am going wrong:
var soundFileURLRef: NSURL!
var audioPlayer = AVAudioPlayer?()
var audioCounter = 0
override func viewDidLoad() {
super.viewDidLoad()
// setup for audio
let playObjects = NSBundle.mainBundle().URLForResource("mathsinfo", withExtension: "mp3")
self.soundFileURLRef = playObjects
do {
audioPlayer = try AVAudioPlayer(contentsOfURL: soundFileURLRef)
} catch _ {
audioPlayer = nil
}
audioPlayer?.delegate = self
audioPlayer?.prepareToPlay()
}
//function for counting times audio is played
func countAudio() {
if ((audioPlayer?.play()) != nil) {
++audioCounter
}
}
//MARK: Actions
//action for button playing the audio
#IBAction func playMathsQuestion(sender: AnyObject) {
countAudio()
if audioCounter < 2 {
audioPlayer?.play()
}
}

Answer 1

The countAudio function in your code have the side effect of playing the sound asynchronously since you call audioPlayer?.play(). The audioCounter variable is only incremented when audioPlayer is nil. Try this version
var soundFileURLRef: NSURL!
var audioPlayer: AVAudioPlayer?
var audioCounter = 0
override func viewDidLoad() {
super.viewDidLoad()
// setup for audio
let playObjects = NSBundle.mainBundle().URLForResource("mathsinfo", withExtension: "mp3")
self.soundFileURLRef = playObjects
audioPlayer = try? AVAudioPlayer(contentsOfURL: soundFileURLRef)
audioPlayer?.delegate = self
audioPlayer?.prepareToPlay()
}
//MARK: Actions
//action for button playing the audio
#IBAction func playMathsQuestion(sender: AnyObject) {
if (audioPlayer != nil) {
if (audioCounter < 2 && audioPlayer!.play()) {
++audioCounter
}
}
}
You can see that here we first check to ensure the audioPlayer is not nil. After this we only do the audioPlayer!.play() call when audioCounter < 2. The call to play() returns a boolean that is true when the audio is successfully queued for play (see the documentation), and in that case we increment audioCounter.
I also simplified the initialization of audioPlayer by using the try? version of try which returns nil when the callee throws.