How to make singleton class from class, which inherits from nsobject and nscoding? - swift

Question

I am trying to make the game settings which loads, saves itself, and makes it singleton class. All my efforts lead to failure, XCode asks me "Cannot invoke initializer for type "Settings" with no arguments". How can I fix this?
This is the code:
class Settings: NSObject, NSCoding {
static let sharedInstance = Settings()
var currentLevel: Int
var positionOfPlayer: [Int]?
var sounds: Bool
var shape: String
var completedLevels: [Int: Bool]
init?(currentLevel: Int, positionOfPlayer: [Int]?, sounds: Bool, shape: String, completedLevels: [Int: Bool]) {
self.currentLevel = currentLevel
self.sounds = sounds
self.shape = shape
self.completedLevels = completedLevels
if let position = positionOfPlayer as [Int]? {
self.positionOfPlayer = position
}
super.init()
}
required convenience init?(coder aDecoder: NSCoder) {
let currentLevel = aDecoder.decodeObjectForKey(SettingNames.nameOfCurrentLevel) as? Int
let completedLevels = aDecoder.decodeObjectForKey(SettingNames.nameOfCompletedLevels) as? [Int: Bool]
let positionOfPlayer = aDecoder.decodeObjectForKey(SettingNames.positionOfPlayerOnCurrentLevel) as? [Int]
let sounds = aDecoder.decodeObjectForKey(SettingNames.nameOfSounds) as? Bool
let shape = aDecoder.decodeObjectForKey(SettingNames.nameOfShapes) as? String
self.init(currentLevel: currentLevel!, positionOfPlayer: positionOfPlayer, sounds: sounds!, shape: shape!, completedLevels: completedLevels!)
}
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeObject(currentLevel, forKey: SettingNames.nameOfCurrentLevel)
aCoder.encodeObject(completedLevels, forKey: SettingNames.nameOfCompletedLevels)
if let position = positionOfPlayer as [Int]? {
// If game canceled or ended during playing, it saves the current player position.
// Next time, when player open the game, it will continue
aCoder.encodeObject(position, forKey: SettingNames.positionOfPlayerOnCurrentLevel)
}
aCoder.encodeBool(sounds, forKey: SettingNames.nameOfSounds)
aCoder.encodeObject(shape, forKey: SettingNames.nameOfShapes)
}
}

Answer 1

You're trying to access a constructor which accepts no parameters which was not implemented for the current class. Try overriding the init method, that should remove the error.
override init(){
// some code
}
Here's a full example I've tried:
import Foundation
class Settings : NSObject, NSCoding {
static let sharedInstance = Settings()
var a: String?
var b: String?
convenience init(a: String, b: String){
self.init()
self.a = a
self.b = b
}
override init(){
}
required init?(coder aDecoder: NSCoder) {
}
func encodeWithCoder(aCoder: NSCoder) {
}
}
Just a point of view: a Singleton that requires you to pass parameters in order to configure it does no longer behave like a singleton.