Swift 2: Can't find audio file path when I use variables as file names

Question

Here's a very strange phenomenon that I'm struggling with:

I'm trying to play an audio file on a button click based on a certain context. For instance if the condition "A" I'll play a certain sound (on button click) and if it is "B" I'd play another sound. I use a switch statement to decide what sounds are played for which condition.

The problem: Even though I'm getting the conditions to work correctly, the AVAudioPlayer always returns nil. But when I hard-code the file to be played, it works just fine. It is only when I use a variable to decide which sound to be played "in the switch statement" is when the sound doesn't play, else when I use a static variable without changing its value, it works fine.

Here's my code:

func playSound(Condition: String){

    switch Condition {
    case "1":
        soundName = "1"
    case "2":
        soundName = "2"
    case "3":
        soundName = "3"
    case "4":
        soundName = "4"
    case "5":
        soundName = "5"
    default:
        soundName = "default"
    }

  let pathString = NSBundle.mainBundle().URLForResource(soundName, withExtension: "m4a")?.path //if I type 'let soundName = "1" or Hard code the value' - it will work fine

    if let soundFilePath = pathString {
        let sound = NSURL.fileURLWithPath(soundFilePath)

        do{
            audioPlayer = try AVAudioPlayer(contentsOfURL:sound)
            audioPlayer.prepareToPlay()
            audioPlayer.play()
        }catch {
            print("Error getting the audio file")
        }
    } else {
        print("Error: Can't find file. Path is nil") // - This is always printed when I use the variable result from the switch
    }
}

Can anyone please help me figure out why? Is the switch taking too long? I doubt because I can print the value of the condition before I play the sound. Thanks in advance.

Added More Information Here: https://forums.developer.apple.com/message/137380#137380

please give more code context, such as where playSound(condition:) is being called. — Alexander
it is called when a button is clicked. The condition is supplied depending on factors such as what day is it, what time is it, etc. — zaam
Okay, wait, are both parts you pasted part of the playSound(condition:) function? — Alexander
Yes, that's one function. So .. there's a button on the UI when pressed this function is called that plays a sound depending on say what time it is. — zaam
There you go, I corrected the formatting. It now appears as a single block of code - one function. — zaam

Ryan Collins Ryan Collins · Accepted Answer · 2016-05-11T03:15:10

You need to declare soundName

I.e.

func playSound(Condition: String){

var soundName: String

switch Condition {
case "1":
    soundName = "1"
case "2":
    soundName = "2"
case "3":
    soundName = "3"
case "4":
    soundName = "4"
case "5":
    soundName = "5"
default:
    soundName = "default"
}

let pathString = NSBundle.mainBundle().URLForResource(soundName, withExtension: "m4a")?.path //if I type 'let soundName = "1" or Hard code the value' - it will work fine

if let soundFilePath = pathString {
    let sound = NSURL.fileURLWithPath(soundFilePath)

    do{
        audioPlayer = try AVAudioPlayer(contentsOfURL:sound)
        audioPlayer.prepareToPlay()
        audioPlayer.play()
    }catch {
        print("Error getting the audio file")
    }
} else {
    print("Error: Can't find file. Path is nil") // - This is always printed when I use the variable result from the switch
}

Swift 2: Can't find audio file path when I use variables as file names

2 Answers