Question

如果这是一个noobie问题再次道歉，但仍然相对较新，所以请耐心等待，

我试图在用户离开页面或关闭应用程序后更改UIViewController中的图像，这个想法是图像被按下密码输入并且图像被更改，（我已经完成了dzk的帮助）和图像应该改变。

但是当我离开应用页面然后再回来时，它已经重置为原始图像，非常令人沮丧！

下面是代码，它将在UIAlertController验证后更改图像。

任何帮助都会感激不尽。

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)


    }

作为附注，是否可以进行主休息动作，将所有图像重置为原始状态？我认为这将是一个if语句？

Answer 1

这是使用NSDefaults的示例。您可以以更符合您需求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检查AppDelegate。你甚至可以通过AppDelegate applicationWillTerminate添加一些延迟或清除保存的密码。

如何永久更改UIViewController中的图像

1 个答案: