SharingMusicPlayer.swift:12:79: Cannot convert value of type 'AVAudioPlayer.Type' to expected argument type 'AVAudioPlayer'

Question

This is what I have in my singleton:

import AVFoundation
import Foundation

class SharingMusicPlayer {
    static let sharingMusicPlayer = SharingMusicPlayer(backgroundMusicPlayer: AVAudioPlayer)
    let backgroundMusicPlayer : AVAudioPlayer

    private init(backgroundMusicPlayer: AVAudioPlayer) {
        self.backgroundMusicPlayer = backgroundMusicPlayer
    }

    func playMusic() {
        // open and play an mp3 file...
    }
}

But I am getting this error:

SharingMusicPlayer.swift:12:79: Cannot convert value of type 'AVAudioPlayer.Type' to expected argument type 'AVAudioPlayer'

Here is another post I have investigated but the solution does not appear to apply here:

"Cannot convert value of type 'AVAudioPlayer.Type' to expected argument type"

BTW, I based my singleton pattern on this article:

https://cocoacasts.com/what-is-a-singleton-and-how-to-create-one-in-swift

Does anyone have any suggestions?

UPDATE:

Please note that I realize that I can play a sound in my app using this code:

run(SKAction.playSoundFileNamed("MySound.mp3", waitForCompletion: false))

But I want to play background music in this case so the above doesn't work.

Answer 1

This is what I came up with, though I am still not sure if this is the right way to do a singleton in swift:

class SharingMusicPlayer {
    static var sharingMusicPlayer = SharingMusicPlayer()
    var backgroundMusicPlayer : AVAudioPlayer?
    
    private init() {
        
    }
    
    func playBackgroundMusic(filename: String) {
        let url = Bundle.main.url(
            forResource: filename, withExtension: nil)
        if (url == nil) {
            print("Could not find file: \(filename)")
            return
        }
        do {
            try self.backgroundMusicPlayer = AVAudioPlayer(contentsOf: url!)
        } catch {
            print("Could not create audio player")
        }
        

        backgroundMusicPlayer!.numberOfLoops = -1
        backgroundMusicPlayer!.prepareToPlay()
        backgroundMusicPlayer!.play()
    }
    
    func stopBackgroundMusic(filename: String) {
        self.backgroundMusicPlayer!.stop()
    }
}

Then this is how I would call the functions to start and stop the music:

override func touchesBegan(_ touches: Set<UITouch>,
                                    with event: UIEvent?) {
   /* Called when a touch begins */
   for touch: AnyObject in touches {
      //1
      let location = touch.location(in:self)
      //2
      let theNode = self.atPoint(location)

      //... 
       
      if theNode.name == playMusicButton!.name {
           print("The \(playMusicButton!.name!) is touched ")
          SharingMusicPlayer.sharingMusicPlayer.playBackgroundMusic(
            filename: "BeethovenPianoSonataNr15InDmajorOp28Pastoral.mp3")
      }

       if theNode.name == stopMusicButton!.name {
            print("The \(stopMusicButton!.name!) is touched ")
           SharingMusicPlayer.sharingMusicPlayer.stopBackgroundMusic()
       }
   }

Please note that the above buttons are in SpriteKit so they are different than the usual UIButton objects in Main.storyboard.

Answer 2

You are passing it the type AVAudioPlayer when you need to pass an instance of AVAudioPlayer. This should work I guess:

Change

static let sharingMusicPlayer = SharingMusicPlayer(backgroundMusicPlayer: AVAudioPlayer)

to

static let sharingMusicPlayer
    = SharingMusicPlayer(backgroundMusicPlayer: AVAudioPlayer())

Update

This is the full code that compiles at my end

class SharingMusicPlayer {
    static let sharingMusicPlayer
        = SharingMusicPlayer(backgroundMusicPlayer: AVAudioPlayer())
    let backgroundMusicPlayer : AVAudioPlayer

    private init(backgroundMusicPlayer: AVAudioPlayer) {
        self.backgroundMusicPlayer = backgroundMusicPlayer
    }

    func playMusic() {
        // open and play an mp3 file...
    }
}