Ios 更改UIImageView图像并使用NSUserDefaults保存

我一直在开发一个应用程序，它允许用户只需按一下按钮就可以切换UIImageView图像。更具体地说，我保存了两个图像，当您按下按钮时，UIImageView图像会发生更改。我对此没有异议。问题是，当我关闭应用程序时，图像会重置为我最初设置为初始UIImageView图像的图像

我在想，有没有办法保留上次选中的图像？换言之：

• 当应用程序启动时，图像被设置为image1
• 用户按下按钮，图像更改为image2
• 用户关闭应用程序并重新打开，除非用户再次点击按钮，否则image2仍然是背景

以下是我目前掌握的代码：

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var backgroundImage: UIImageView!


let lightBG = UIImage(named: "bg1.jpg")
let darkBG = UIImage(named: "bg2.jpg")

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


@IBAction func changeBG(sender: AnyObject) {
    if(backgroundImage.image == lightBG){
        backgroundImage.image = darkBG
    }
    else{
        backgroundImage.image = lightBG
    }
}

}

---

更好的选择是在

NSUserDefaults

中保存

Boolean

，而不是保存整个图像

@IBAction func changeBG(sender: AnyObject) {

    if(backgroundImage.image == lightBG){
        backgroundImage.image = darkBG
        NSUserDefaults.standardUserDefaults().setBool(true, forKey: "IMAGE_DARK_SET")
        NSUserDefaults.standardUserDefaults().setBool(false, forKey: "IMAGE_LIGHT_SET")
    }
    else{
        backgroundImage.image = lightBG
        NSUserDefaults.standardUserDefaults().setBool(true, forKey: "IMAGE_LIGHT_SET")
        NSUserDefaults.standardUserDefaults().setBool(false, forKey: "IMAGE_DARK_SET")
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    if NSUserDefaults.standardUserDefaults().boolForKey("IMAGE_LIGHT_SET"){

        backgroundImage.image = lightBG

    }else if NSUserDefaults.standardUserDefaults().boolForKey("IMAGE_DARK_SET"){

        backgroundImage.image = darkBG
    }
}

---

希望这有帮助

更好的选择是在

NSUserDefaults

中保存一个

布尔值，而不是整个图像

@IBAction func changeBG(sender: AnyObject) {

    if(backgroundImage.image == lightBG){
        backgroundImage.image = darkBG
        NSUserDefaults.standardUserDefaults().setBool(true, forKey: "IMAGE_DARK_SET")
        NSUserDefaults.standardUserDefaults().setBool(false, forKey: "IMAGE_LIGHT_SET")
    }
    else{
        backgroundImage.image = lightBG
        NSUserDefaults.standardUserDefaults().setBool(true, forKey: "IMAGE_LIGHT_SET")
        NSUserDefaults.standardUserDefaults().setBool(false, forKey: "IMAGE_DARK_SET")
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    if NSUserDefaults.standardUserDefaults().boolForKey("IMAGE_LIGHT_SET"){

        backgroundImage.image = lightBG

    }else if NSUserDefaults.standardUserDefaults().boolForKey("IMAGE_DARK_SET"){

        backgroundImage.image = darkBG
    }
}

希望这有帮助
 第一步

 override func viewDidLoad() {
   super.viewDidLoad()

     // Initially Check your `NSUserDefaults` key is empty or not 

       if NSUserDefaults.standardUserDefaults().objectForKey("SaveImage") != nil  
   {
    // If it is not empty , load the `NSUserDefaults` Image
   backgroundImage.image = UIImage(named: NSUserDefaults.standardUserDefaults().objectForKey("SaveImage"))

   }
else
 {
  // if above condition is not statisfy load the normal Image
  backgroundImage.image = lightBG
  }
}


 @IBAction func changeBG(sender: AnyObject) {

    if(backgroundImage.image == lightBG){
        backgroundImage.image = darkBG
           }
    else{
        backgroundImage.image = lightBG

    }

// On your button click , load the last selected Image , thats all
 NSUserDefaults.standardUserDefaults().setObject(backgroundImage.image, forKey: "SaveImage")


}

步骤1

 override func viewDidLoad() {
   super.viewDidLoad()

     // Initially Check your `NSUserDefaults` key is empty or not 

       if NSUserDefaults.standardUserDefaults().objectForKey("SaveImage") != nil  
   {
    // If it is not empty , load the `NSUserDefaults` Image
   backgroundImage.image = UIImage(named: NSUserDefaults.standardUserDefaults().objectForKey("SaveImage"))

   }
else
 {
  // if above condition is not statisfy load the normal Image
  backgroundImage.image = lightBG
  }
}


 @IBAction func changeBG(sender: AnyObject) {

    if(backgroundImage.image == lightBG){
        backgroundImage.image = darkBG
           }
    else{
        backgroundImage.image = lightBG

    }

// On your button click , load the last selected Image , thats all
 NSUserDefaults.standardUserDefaults().setObject(backgroundImage.image, forKey: "SaveImage")


}

您可以通过几种方式保存选定的图像。一种是在视图退出或用户更改图像时，在用户默认设置中保存图像的名称

以下是当用户更改图像时如何保存它：

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var backgroundImage: UIImageView!

let kBGImageNameKey = "bgImageName"

let lightBG = UIImage(named: "bg1.jpg")
let darkBG = UIImage(named: "bg2.jpg")

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    let defaults = NSUserDefaults.standardUserDefaults()
    if let name = defaults.stringForKey(kBGImageNameKey) {
        if (name == "bg1.jpg") {
            backgroundImage.image = lightBG
        } else {
            backgroundImage.image = darkBG
        }
    } 
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


@IBAction func changeBG(sender: AnyObject) {
    let defaults = NSUserDefaults.standardUserDefaults()

    if(backgroundImage.image == lightBG){
        backgroundImage.image = darkBG
        defaults.setObject("bg2.jpg", forKey: kBGImageNameKey)
    }
    else{
        backgroundImage.image = lightBG
        defaults.setObject("bg1.jpg", forKey: kBGImageNameKey)
    }
}

}

这只是一种方法，只是为了给你指明方向。
你可以用几种方法保存选定的图像。一种是在视图退出或用户更改图像时，在用户默认设置中保存图像的名称

以下是当用户更改图像时如何保存它：

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var backgroundImage: UIImageView!

let kBGImageNameKey = "bgImageName"

let lightBG = UIImage(named: "bg1.jpg")
let darkBG = UIImage(named: "bg2.jpg")

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    let defaults = NSUserDefaults.standardUserDefaults()
    if let name = defaults.stringForKey(kBGImageNameKey) {
        if (name == "bg1.jpg") {
            backgroundImage.image = lightBG
        } else {
            backgroundImage.image = darkBG
        }
    } 
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


@IBAction func changeBG(sender: AnyObject) {
    let defaults = NSUserDefaults.standardUserDefaults()

    if(backgroundImage.image == lightBG){
        backgroundImage.image = darkBG
        defaults.setObject("bg2.jpg", forKey: kBGImageNameKey)
    }
    else{
        backgroundImage.image = lightBG
        defaults.setObject("bg1.jpg", forKey: kBGImageNameKey)
    }
}

}

这只是一种方法，只是为了让您朝着正确的方向前进。
将一个设置为true时，您必须将另一个设置为false。或者只需使用一个键并设置为true或false。您当前的解决方案将在两次切换后都为真，并且将始终设置为亮背景。@kRiZ Oops！忘记谢谢你的建议。我已经更新了代码，当一个设置为真时，你必须将另一个设置为假。或者只需使用一个键并设置为true或false。您当前的解决方案将在两次切换后都为真，并且将始终设置为亮背景。@kRiZ Oops！忘记谢谢你的建议。我已经更新了代码是的，我都试过了。这是我最理解的一个，因为你在顶部的小小解释。因为我在bg1的故事板中有UIImageView，所以您的回答对我很有帮助。非常感谢。（很高兴我能帮上忙。）快乐编码是的，我都试过了。这是我最理解的一个，因为你在顶部的小小解释。因为我在bg1的故事板中有UIImageView，所以您的回答对我很有帮助。非常感谢。（很高兴我能帮上忙）很高兴