How to play custom audio on Swift Playgrounds for iPad, using UIKit. Replace "slow-spring-board" with the name of your audio file.

iPadSwiftPlaygrounds_PlayAudio_UIKit.swift

import AVFoundation
import SwiftUI
import PlaygroundSupport

class UIKitAudioPlayerView: UIView {
    
    /// the audio player that will play your audio file. Can't be a local variable.
    var audioPlayer: AVAudioPlayer?
    
    /// so we only make and connect the button once
    var hasLoadedView = false
    var audioButton = UIButton()
    
    /// the view is guarenteed to be loaded at `layoutSubviews()` 
    override func layoutSubviews() {
        super.layoutSubviews()
        
        if !hasLoadedView {
            hasLoadedView = true
            
            audioButton.setTitle("Play Audio!", for: .normal)
            audioButton.setTitleColor(UIColor.blue, for: .normal)
            backgroundColor = .white
            
            addSubview(audioButton) /// add the button to the view
            audioButton.addTarget(self, action: #selector(playAudio), for: .touchUpInside)
        }
        
        /// positioning (center-align the button)
        let middleXOfView = bounds.width / 2
        let middleYOfView = bounds.height / 2
        let buttonFrame = CGRect(x: middleXOfView - 60, y: middleYOfView - 20, width: 120, height: 40)
        audioButton.frame = buttonFrame
    }
    
    @objc func playAudio() { /// function to play audio
        
        /// the URL of the audio file.
        /// forResource = name of the file. 
        /// withExtension = extension, usually "mp3"
        if let audioURL = Bundle.main.url(forResource: "slow-spring-board", withExtension: "mp3") {
            do {
                try self.audioPlayer = AVAudioPlayer(contentsOf: audioURL) /// make the audio player
                self.audioPlayer?.numberOfLoops = 0 /// Number of times to loop the audio
                self.audioPlayer?.play() /// start playing
                
            } catch {
                print("Couldn't play audio. Error: \(error)")
            }
            
        } else {
            print("No audio file found")
        }
    }
}

let uikitAudioPlayerView = UIKitAudioPlayerView()
PlaygroundPage.current.setLiveView(uikitAudioPlayerView)

Before any of the code, you need to first have an audio file saved in the built-in Files app. Then, you must import it into your Swift Playgrounds project:

1. Press the "+" icon
2. Tap the paper icon
3. Tap Insert From…, then select your audio file

Then replace "slow-spring-board" with its name.

SwiftUI version