Save UIImage array in NSUserDefaults

问题:

I want to put a UIImage array into UserDefaults and then retrieve it. After that set the retrieved images in an image view. How can I do that?

回答1:

You can easily save your image in documentDirectory as below:

let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first let fileURL = documentDirectory?.appendingPathComponent(yourImageName)

and then, you can give your image to UserDefaults

回答2:

First of all that is not ideal way to save image in user default but if you want you can do following things

Save

let imageData = NSKeyedArchiver.archivedData(withRootObject: placesArray)
UserDefaults.standard.set(imageData, forKey: "images")

Retrieve

       let imageData = UserDefaults.standard.object(forKey: "images") as? NSData

        if let imageData = imageData {
            let imageArray = NSKeyedUnarchiver.unarchiveObject(with: imageData as Data) as? [UIImage]!
            print(placesArray)
        }

Note: You should save your image in document directory and then save that name array to user default.

Save image in document directory

func saveImageDocumentDirectory(){
        let fileManager = NSFileManager.defaultManager()
        let paths = (NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSString).stringByAppendingPathComponent("apple.jpg")
        let image = UIImage(named: "apple.jpg")
        print(paths)
        let imageData = UIImageJPEGRepresentation(image!, 0.5)
        fileManager.createFileAtPath(paths as String, contents: imageData, attributes: nil)
    }

Retrieve image

func getImage(name : String){
        let fileManager = NSFileManager.defaultManager()
        let imagePAth = (self.getDirectoryPath() as NSString).stringByAppendingPathComponent(name)
        if fileManager.fileExistsAtPath(imagePAth){
            self.imageView.image = UIImage(contentsOfFile: imagePAth)
        }else{
            print("No Image")
        }
    }

func getDirectoryPath() -> String {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let documentsDirectory = paths[0]
    return documentsDirectory
}

回答3:

Simple approach, convert UIImages to NSData. Then add image data’s into an NSArray. Then save the NSArray into UserDefault. When retrieving the NSArray from UserDefault,use ImageWithData method to render UIImage from the NSArray’s each elements. This is the easiest process if you really one to use UserDefaults for your purpose. Try this yourself.

回答4:

That's really bad idea if you really going to do that. You should save image in DocumentDirectory and save images name in NSUserDefaults.

func saveImages(images:[UIImage]) {

     let fileManager = FileManager.default
     let path = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString) 
     var imagesNames = [String]()


    do {

        if !fileManager.fileExists(atPath: path as String){
            try fileManager.createDirectory(atPath: path as String, withIntermediateDirectories: true, attributes: nil)
        }

     for (index,image) in images.enumarated() {
        let imageName = "Image\(index).jpg"
        let imageData = UIImageJPEGRepresentation(image, 1.0)
        if fileManager.createFile(atPath: paths.appending("/\(file)") as String, contents: imageData, attributes: nil) {
         imagesNames.append(imageName)
        }
      }
     let storage = UserDefaults.standard
     storage.set(imagesNames, forKey: "imagesArray")
     storage.synchronize()

    }catch{
        //Throw Error
    } 
}