I have a class called Sound from the framework SwiftySound and a subclass called SoundWrapper which makes it hashable. Now I am adding a string property "imageName" to the subclass so that I can add an image to every sound. Therefore, I am required to write an initializer for the superclass using super.init.
However, when I try to do that the error shows: 'url' is inaccessible due to 'private' protection level.
Is there any way to resolve this?
To be clear, this is my first time creating subclasses in Swift so I could be making some obvious mistakes here and might need a different approach altogether.
This is my subclass:
class SoundWrapper:Sound, Hashable{
let id = UUID()
let imageName : String
init(imageName: String) {
self.imageName = imageName
super.init(url: url)
// Error: 'url' is inaccessible due to 'private' protection level
}
public func hash(into hasher: inout Hasher) {
hasher.combine(0)
}
static func == (lhs: SoundWrapper, rhs: SoundWrapper) -> Bool {
return lhs.id == rhs.id
}
}
How I plan to initialize the subclass:
let backgroundAudio1 = SoundWrapper(imageName: "image1", url: getFileUrl(name: "backgroundAudio1"))
How I get the url:
func getFileUrl (name: String) -> URL {
let filePath = Bundle.main.path(forResource: name, ofType: "wav")!
return URL(fileURLWithPath: filePath)
}
This is the SwiftySound framework where I get the Sound class from:
import Foundation
import AVFoundation
#if os(iOS) || os(tvOS)
/// SoundCategory is a convenient wrapper for AVAudioSessions category constants.
public enum SoundCategory {
/// Equivalent of AVAudioSession.Category.ambient.
case ambient
/// Equivalent of AVAudioSession.Category.soloAmbient.
case soloAmbient
/// Equivalent of AVAudioSession.Category.playback.
case playback
/// Equivalent of AVAudioSession.Category.record.
case record
/// Equivalent of AVAudioSession.Category.playAndRecord.
case playAndRecord
fileprivate var avFoundationCategory: AVAudioSession.Category {
get {
switch self {
case .ambient:
return .ambient
case .soloAmbient:
return .soloAmbient
case .playback:
return .playback
case .record:
return .record
case .playAndRecord:
return .playAndRecord
}
}
}
}
#endif
/// Sound is a class that allows you to easily play sounds in Swift. It uses AVFoundation framework under the hood.
open class Sound {
// MARK: - Global settings
/// Number of AVAudioPlayer instances created for every sound. SwiftySound creates 5 players for every sound to make sure that it will be able to play the same sound more than once. If your app doesn't need this functionality, you can reduce the number of players to 1 and reduce memory usage. You can increase the number if your app plays the sound more than 5 times at the same time.
public static var playersPerSound: Int = 10 {
didSet {
stopAll()
sounds.removeAll()
}
}
#if os(iOS) || os(tvOS)
/// Sound session. The default value is the shared `AVAudioSession` session.
public static var session: Session = AVAudioSession.sharedInstance()
/// Sound category for current session. Using this variable is a convenient way to set AVAudioSessions category. The default value is .ambient.
public static var category: SoundCategory = {
let defaultCategory = SoundCategory.ambient
try? session.setCategory(defaultCategory.avFoundationCategory)
return defaultCategory
}() {
didSet {
try? session.setCategory(category.avFoundationCategory)
}
}
#endif
private static var sounds = [URL: Sound]()
private static let defaultsKey = "com.moonlightapps.SwiftySound.enabled"
/// Globally enable or disable sound. This setting value is stored in UserDefaults and will be loaded on app launch.
public static var enabled: Bool = {
return !UserDefaults.standard.bool(forKey: defaultsKey)
}() { didSet {
let value = !enabled
UserDefaults.standard.set(value, forKey: defaultsKey)
if value {
stopAll()
}
}
}
private let players: [Player]
private var counter = 0
/// The class that is used to create `Player` instances. Defaults to `AVAudioPlayer`.
public static var playerClass: Player.Type = AVAudioPlayer.self
/// The bundle used to load sounds from filenames. The default value of this property is Bunde.main. It can be changed to load sounds from another bundle.
public static var soundsBundle: Bundle = .main
// MARK: - Initialization
/// Create a sound object.
///
/// - Parameter url: Sound file URL.
public init?(url: URL) {
#if os(iOS) || os(tvOS)
_ = Sound.category
#endif
let playersPerSound = max(Sound.playersPerSound, 1)
var myPlayers: [Player] = []
myPlayers.reserveCapacity(playersPerSound)
for _ in 0..<playersPerSound {
do {
let player = try Sound.playerClass.init(contentsOf: url)
myPlayers.append(player)
} catch {
print("SwiftySound initialization error: \(error)")
}
}
if myPlayers.count == 0 {
return nil
}
players = myPlayers
NotificationCenter.default.addObserver(self, selector: #selector(Sound.stopNoteRcv), name: Sound.stopNotificationName, object: nil)
}
deinit {
NotificationCenter.default.removeObserver(self, name: Sound.stopNotificationName, object: nil)
}
@objc private func stopNoteRcv() {
stop()
}
private static let stopNotificationName = Notification.Name("com.moonlightapps.SwiftySound.stopNotification")
// MARK: - Main play method
/// Play the sound.
///
/// - Parameter numberOfLoops: Number of loops. Specify a negative number for an infinite loop. Default value of 0 means that the sound will be played once.
/// - Returns: If the sound was played successfully the return value will be true. It will be false if sounds are disabled or if system could not play the sound.
@discardableResult public func play(numberOfLoops: Int = 0, completion: PlayerCompletion? = nil) -> Bool {
if !Sound.enabled {
return false
}
paused = false
counter = (counter 1) % players.count
let player = players[counter]
return player.play(numberOfLoops: numberOfLoops, completion: completion)
}
// MARK: - Stop playing
/// Stop playing the sound.
public func stop() {
for player in players {
player.stop()
}
paused = false
}
/// Pause current playback.
public func pause() {
players[counter].pause()
paused = true
}
/// Resume playing.
@discardableResult public func resume() -> Bool {
if paused {
players[counter].resume()
paused = false
return true
}
return false
}
/// Indicates if the sound is currently playing.
public var playing: Bool {
return players[counter].isPlaying
}
/// Indicates if the sound is paused.
public private(set) var paused: Bool = false
// MARK: - Prepare sound
/// Prepare the sound for playback
///
/// - Returns: True if the sound has been prepared, false in case of error
@discardableResult public func prepare() -> Bool {
let nextIndex = (counter 1) % players.count
return players[nextIndex].prepareToPlay()
}
// MARK: - Convenience static methods
/// Play sound from a sound file.
///
/// - Parameters:
/// - file: Sound file name.
/// - fileExtension: Sound file extension.
/// - numberOfLoops: Number of loops. Specify a negative number for an infinite loop. Default value of 0 means that the sound will be played once.
/// - Returns: If the sound was played successfully the return value will be true. It will be false if sounds are disabled or if system could not play the sound.
@discardableResult public static func play(file: String, fileExtension: String? = nil, numberOfLoops: Int = 0) -> Bool {
if let url = url(for: file, fileExtension: fileExtension) {
return play(url: url, numberOfLoops: numberOfLoops)
}
return false
}
/// Play a sound from URL.
///
/// - Parameters:
/// - url: Sound file URL.
/// - numberOfLoops: Number of loops. Specify a negative number for an infinite loop. Default value of 0 means that the sound will be played once.
/// - Returns: If the sound was played successfully the return value will be true. It will be false if sounds are disabled or if system could not play the sound.
@discardableResult public static func play(url: URL, numberOfLoops: Int = 0) -> Bool {
if !Sound.enabled {
return false
}
var sound = sounds[url]
if sound == nil {
sound = Sound(url: url)
sounds[url] = sound
}
return sound?.play(numberOfLoops: numberOfLoops) ?? false
}
/// Stop playing sound for given URL.
///
/// - Parameter url: Sound file URL.
public static func stop(for url: URL) {
let sound = sounds[url]
sound?.stop()
}
/// Duration of the sound.
public var duration: TimeInterval {
get {
return players[counter].duration
}
}
/// Sound volume.
/// A value in the range 0.0 to 1.0, with 0.0 representing the minimum volume and 1.0 representing the maximum volume.
public var volume: Float {
get {
return players[counter].volume
}
set {
for player in players {
player.volume = newValue
}
}
}
/// Stop playing sound for given sound file.
///
/// - Parameters:
/// - file: Sound file name.
/// - fileExtension: Sound file extension.
public static func stop(file: String, fileExtension: String? = nil) {
if let url = url(for: file, fileExtension: fileExtension) {
let sound = sounds[url]
sound?.stop()
}
}
/// Stop playing all sounds.
public static func stopAll() {
NotificationCenter.default.post(name: stopNotificationName, object: nil)
}
// MARK: - Private helper method
private static func url(for file: String, fileExtension: String? = nil) -> URL? {
return soundsBundle.url(forResource: file, withExtension: fileExtension)
}
}
/// Player protocol. It duplicates `AVAudioPlayer` methods.
public protocol Player: AnyObject {
/// Play the sound.
///
/// - Parameters:
/// - numberOfLoops: Number of loops.
/// - completion: Complation handler.
/// - Returns: true if the sound was played successfully. False otherwise.
func play(numberOfLoops: Int, completion: PlayerCompletion?) -> Bool
/// Stop playing the sound.
func stop()
/// Pause current playback.
func pause()
/// Resume playing.
func resume()
/// Prepare the sound.
func prepareToPlay() -> Bool
/// Create a Player for sound url.
///
/// - Parameter url: sound url.
init(contentsOf url: URL) throws
/// Duration of the sound.
var duration: TimeInterval { get }
/// Sound volume.
var volume: Float { get set }
/// Indicates if the player is currently playing.
var isPlaying: Bool { get }
}
fileprivate var associatedCallbackKey = "com.moonlightapps.SwiftySound.associatedCallbackKey"
public typealias PlayerCompletion = ((Bool) -> ())
extension AVAudioPlayer: Player, AVAudioPlayerDelegate {
public func play(numberOfLoops: Int, completion: PlayerCompletion?) -> Bool {
if let cmpl = completion {
objc_setAssociatedObject(self, &associatedCallbackKey, cmpl, .OBJC_ASSOCIATION_COPY_NONATOMIC)
self.delegate = self
}
self.numberOfLoops = numberOfLoops
return play()
}
public func resume() {
play()
}
public func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) {
let cmpl = objc_getAssociatedObject(self, &associatedCallbackKey) as? PlayerCompletion
cmpl?(flag)
objc_removeAssociatedObjects(self)
self.delegate = nil
}
public func audioPlayerDecodeErrorDidOccur(_ player: AVAudioPlayer, error: Error?) {
print("SwiftySound playback error: \(String(describing: error))")
}
}
#if os(iOS) || os(tvOS)
/// Session protocol. It duplicates `setCategory` method of `AVAudioSession` class.
public protocol Session: AnyObject {
/// Set category for session.
///
/// - Parameter category: category.
func setCategory(_ category: AVAudioSession.Category) throws
}
extension AVAudioSession: Session {}
#endif
CodePudding user response：
Sound provides one public initializer that expects a URL parameter. Your wrapper also need to take a URL parameter so it can pass it on.
init(imageName: String, url: URL) {
self.imageName = imageName
super.init(url: url)
}
You needed a URL when creating Sound instances. You will need the same URL when creating SoundWrapper instances.
Also note that your hash is kind of inefficient using 0 for all instances. Why not use id?
public func hash(into hasher: inout Hasher) {
hasher.combine(id)
}
CodePudding user response：
You don't define url anywhere on SoundWrapper so the Swift compiler is trying to find where url is defined elsewhere. I believe it is finding the private method on Sound: private static func url(for file: String, fileExtension: String? = nil) -> URL? and telling you that it is private.
So the question is, what url do you actually want to pass into the Sound base class initializer?
I imagine that your SoundWrapper initialiszer would be changed to look something like:
init(imageName: String) {
self.imageName = imageName
super.init(url: URL(string: "example.com")!)
// or use a URL defined on your class or somewhere else
}