再次道歉，如果这是一个noobie问题，但还是比较新的，请耐心等待，
我试图在UIViewController中更改图像，即使用户已经离开页面或关闭应用程序之后，我的想法是按下图像并输入密码并更改了图像（我已经在dzk的帮助下完成了此操作） ），并且图像会发生变化。
但是当我离开应用程序页面然后返回时，它已重置为原始图像，真令人沮丧！
下面是按原样编写的代码，它将在验证UIAlertController之后更改图像。
任何帮助将不胜感激。
class Man_VS_Cocktail : UIViewController{
@IBOutlet weak var Cocktail_Image: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nil
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func Cocktail_check_button(sender: AnyObject) {
var password_Text: UITextField?
let alertController = UIAlertController(title: "One more ticked off", message: "ask the barman to enter the password", preferredStyle: UIAlertControllerStyle.Alert)
let tickoff_action = UIAlertAction(title: "sign it off", style: UIAlertActionStyle.Default) {
action -> Void in
if let password = password_Text?.text{
print("password = \(password)")
if password == "pass123" {
self.Cocktail_Image.image = UIImage(named: "riddler_question_marks")
}
} else {
print("No password entered")
}
}
alertController.addTextFieldWithConfigurationHandler { (txtpassword) -> Void in
password_Text = txtpassword
password_Text!.secureTextEntry = true
password_Text!.placeholder = ""
}
alertController.addAction(tickoff_action)
self.presentViewController(alertController, animated: true, completion: nil)
}
附带说明一下，是否可以执行主休息操作将所有图像重置为其原始状态？我认为这将是一个if语句？
最佳答案
这是有关使用NSDefaults的示例。您可以按照更适合自己的方式进行更改和格式化。
class Man_VS_Cocktail : UIViewController{
let defaults: NSUserDefaults
@IBOutlet weak var Cocktail_Image: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// Check saved password.
let passSaved = defaults.stringForKey("password")
if passSaved == "pass123" {
self.Cocktail_Image.image = UIImage(named: "riddler_question_marks")
} else {
// Set default image.
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func Cocktail_check_button(sender: AnyObject) {
var password_Text: UITextField?
let alertController = UIAlertController(title: "One more ticked off", message: "ask the barman to enter the password", preferredStyle: UIAlertControllerStyle.Alert)
let tickoff_action = UIAlertAction(title: "sign it off", style: UIAlertActionStyle.Default) {
action -> Void in
if let password = password_Text?.text{
print("password = \(password)")
if password == "pass123" {
// Save the password
self.defaults.setObject(password_Text, forKey: "password")
// End save password
self.Cocktail_Image.image = UIImage(named: "riddler_question_marks")
}
} else {
print("No password entered")
}
}
alertController.addTextFieldWithConfigurationHandler { (txtpassword) -> Void in
password_Text = txtpassword
password_Text!.secureTextEntry = true
password_Text!.placeholder = ""
}
alertController.addAction(tickoff_action)
self.presentViewController(alertController, animated: true, completion: nil)
}
您甚至可以使用相同的格式签入您的AppDelegate。您甚至可以添加某种延迟，或者通过AppDelegate applicationWillTerminate清除保存的密码。