I have an audio player that starts on my home screen - swift2

Question

Whenever I go back to my home screen it replays the music over the already playing music. I tried making an if statements that 'obviously' doesn't work (because I barely know any swift!). Here is my home screen code:
var myAudioPlayer = AVAudioPlayer()
override func viewDidLoad() {
let myFilePathString =
NSBundle.mainBundle().pathForResource("16 March of the Resistance", ofType: "m4a")
if let myFilePathString = myFilePathString
{
let myFilePathURL = NSURL(fileURLWithPath: myFilePathString)
do{
try myAudioPlayer = AVAudioPlayer(contentsOfURL: myFilePathURL)
myAudioPlayer.play()
}catch
{
print("error")
}
}
}
How can I stop it from playing on top of itself?
Here is a picture of my storyboard
enter image description here
The music player is on StartScreen, but when I click the back button, it starts another music player over the current one.
I need code which says
is myAudioPlayer playing?
if yes do not play song again
else play "16 March of the resistance"
enter image description here

Answer 1

You need to check if you are already playing. You can do this by the playing property of the AVAudioPlayer class.
Guard your viewDidLoad with say:
if !myAudioPlayer.playing
Note that I don't know any Swift.

Answer 2

I'm not sure what you mean by "my home screen", is it the device or your main VC? Why are you overriding viewDidLoad()? A previous player could never be playing in the viewDidLoad() call, unless for a leak which is what's needing fixing.
Otherwise, you just need to declare your player as an optional, rather than creating it in the declaration. As for the replaying or overlapping, just check if you player exists, although you wouldnt do this in your viewDidLoad(). ViewDidLoad() is called when the view of the VC is created and the view loaded, which doesn't relate to your lifecycle of the audio.
Depending on your requirements, you might want to create the player somewhere else that is plays throughout the app, rather than restarting when visiting that VC. Otherwise the code below will avoid the duplication. The problem was this var myAudioPlayer = AVAudioPlayer() which would duplicate players and one wasn't being released.
var myAudioPlayer: AVAudioPlayer?
func viewDidLoad() {
// this should never be needed with correct player setup
if let player = myAudioPlayer where player.playing {
return
}
if let pathString = NSBundle.mainBundle().pathForResource("16 March of the Resistance", ofType: "m4a")
{
let url = NSURL(fileURLWithPath: pathString)
do{
try myAudioPlayer = AVAudioPlayer(contentsOfURL: url)
myAudioPlayer?.play()
} catch {
print("error")
}
}
}
Update
So there is no need to make the VC do this. Create a Class of e.g. AudioController, which could even be a singleton. Initialise it in your AppDelegate and trigger this player setup code after initialisation. Your view controllers dont need to know about the audio controller. IF e.g. you do want to modify the volume from a setting page, you just access the singleton object and set its volume.
This way you keep all your audio controller code nicely separated. Dont just think of functionality, think of overall software architecture, with objects having clear responsibilities. Keep your ViewControllers light, they shouldnt be doing much processing.
Take a look at this Singletons , its really easy to setup a singleton in Swift nowadays.
class AudioController {
static let sharedInstance = AudioController()
var audioPlayer: AVAudioPlayer?
let kVolumeKey = "VolumeKey"
let kHasSavedInitialVolumeKey = "HasSavedInitialVolumeKey"
var volume: Float = 0.5
func setup() {
self.loadVolume()
self.setupPlayer()
}
func updatePlayerVolume(volume: Float) {
self.audioPlayer?.volume = volume
self.volume = volume
self.saveVolume()
}
func saveVolume() {
NSUserDefaults.standardUserDefaults().setBool(true, forKey: kHasSavedInitialVolumeKey)
NSUserDefaults.standardUserDefaults().setFloat(self.volume, forKey: kVolumeKey)
NSUserDefaults.standardUserDefaults().synchronize()
}
func loadVolume() {
if NSUserDefaults.standardUserDefaults().boolForKey(kHasSavedInitialVolumeKey) {
self.volume = NSUserDefaults.standardUserDefaults().floatForKey(kVolumeKey)
}
}
func setupPlayer() {
if let pathString = NSBundle.mainBundle().pathForResource("16 March of the Resistance", ofType: "m4a")
{
let url = NSURL(fileURLWithPath: pathString)
do{
try audioPlayer = AVAudioPlayer(contentsOfURL: url)
audioPlayer?.volume = self.volume
audioPlayer?.play()
} catch {
print("error")
}
}
}
}
So, you can just setup the player from your AppDelegate's didFinishLaunching
AudioController.sharedInstance.setupPlayer()
And then you can access the AudioController using AudioController.sharedInstance.whatever when you need to get or set. Also, you will need to implement the players delegate methods for handling the end of the song, possibly triggering a new song to play from a playlist(create a new object for this) or whatever. Your player delegate code is also nicely separated now.

Answer 3

Looking at your storyboard it seems that when you click the Back button on the second ViewController you allocate another start screen and you push it on the screen.
It seems that you're using a UINavigationController if so when the back button is tapped you should call:
self.navigationController?.popViewControllerAnimated(true)
If your showing it as a modal you should dismiss is like this:
self.dismissViewControllerAnimated(true, completion: nil)