在Swift 4.0.3 Xcode 9

============set  Data in UserDefaults =========

  UserDefaults.standard.set(userName, forKey: "userName")
  UserDefaults.standard.synchronize()

============Get Data in UserDefaults =========

  let userName = UserDefaults.standard.string(forKey: "userName")
  print(userName ?? "Gera")

  userNameTextField.text = ""+userName!

在Swift 4.0.3 Xcode 9

============set  Data in UserDefaults =========

  UserDefaults.standard.set(userName, forKey: "userName")
  UserDefaults.standard.synchronize()

============Get Data in UserDefaults =========

  let userName = UserDefaults.standard.string(forKey: "userName")
  print(userName ?? "Gera")

  userNameTextField.text = ""+userName!

[nsusudefaults默认:aString forKey:aKey]

斯威夫特更新了:

let userID = "BOB"  

宣布userDefaults:

let defaults = UserDefaults.standard
defaults.setValue(userID, forKey: "userID")

并得到它:

let userID = defaults.object(forKey: "userID")

下面是如何对Swift做同样的事情;

var valueToSave = "someValue"
NSUserDefaults.standardUserDefaults().setObject(valueToSave, forKey: "preferenceName")

以后把它拿回来;

if let savedValue = NSUserDefaults.standardUserDefaults().stringForKey("preferenceName") {
    // Do something with savedValue
}

在Swift 3.0中

var valueToSave = "someValue"
UserDefaults.standard.set(valueToSave, forKey: "preferenceName")

if let savedValue = UserDefaults.standard.string(forKey: "preferenceName") {

}

不要忘记这句话，否则它可能并不总是有效:

[standardUserDefaults synchronize];