Userdefaults not working

Question

有人可以幫助我，爲什麼我無法正確執行nsuserdefaults。當我嘗試點擊保存時，它什麼都不做。我想要的是當我點擊保存它將保存到手機，然後當我嘗試再次返回到viewcontroller它會出現。以下是我的代碼如下。

override func viewDidLoad() { 
    super.viewDidLoad() 

    self.navigationItem.setHidesBackButton(true, animated: false) 
    self.hideKeyboardWhenTappedAround() 

    firstName.delegate = self 
    lastName.delegate = self 

    tableView.reloadData() 

    //Save Defaults 
    let defaults = UserDefaults.standard 
    if let _ = defaults.object(forKey: "firstName") as? String { 
     self.firstName.text = defaults.object(forKey: "firstName") as? String 
    } 

    if let _ = defaults.object(forKey: "lastName") as? String { 
     self.lastName.text = defaults.object(forKey: "lastName") as? String 
    } 

    if let _ = defaults.object(forKey: "contacts") as? Array<Any> { 
     self.contacts = (defaults.object(forKey: "contacts") as? Array)! 
    } 
} 



//MARK -> SAVE BUTTON 
    @IBAction func saveButtonSelected(_ sender: AnyObject) { 
      let defaults: UserDefaults = UserDefaults.standard 
      defaults.set(self.firstName.text, forKey: "firstName") 
      defaults.set(self.lastName.text, forKey: "lastName") 
      defaults.set(contacts, forKey: "contacts") 
     } 

Answer 1

試試這個：

@IBAction func saveButtonSelected(_ sender: AnyObject) { 
       let defaults: UserDefaults = UserDefaults.standard 
       defaults.set(self.firstName.text, forKey: "firstName") 
       defaults.set(self.lastName.text, forKey: "lastName") 
       defaults.set(contacts, forKey: "contacts") 
       defaults.synchronize() 
      }