How to use UserDefaults?

UserDefaults is a singleton object. For more details, please check my singleton-object.md file.

An interface to the user’s defaults database, where you store key-value pairs persistently across launches of your app. - developer.apple.com

Usage

  • Create a new instence.
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let defaults = UserDefaults.standard
  • set data
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defaults.set(0.24, forKey: "Volume")
defaults.set("Ohaok", forKey: "PlayerName")
defaults.set(Date(), forKey: "AppLastOpenedByUser")

let array = [1, 2, 3, 4]
defaults.set(array, forKey: "myArray")

let dictionary = [404: "page not found", 200: "Ok"]
// defaults.set(dictionary, forKey: "statusCodes") // error ?
  • get data
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let volume = defaults.float(forKey: "Volume")
let playerName = defaults.string(forKey: "PlayerName")
let appLastOpened = defaults.object(forKey: "AppLastOpenedByUser")

let myArray = defaults.array(forKey: "myArray") as! [Int] // because set optional
let myDictionary = defaults.dictionary(forKey: "statusCodes")