Swift 3.0：如何从 imagePicker 将用户的图像保存在应用程序中

Question

我试图让用户从他们的图库或相机中选择一张图片，然后将其上传到应用程序。这可行，但唯一的问题是它没有将其保存在应用程序中。一旦用户关闭应用程序，用户选择的图像就会消失。我也没有任何保存功能，因为我不知道如何实现。

我在 Swift 3.0 中使用 Xcode 8.3.2。下面是代码：

    import UIKit

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    @IBOutlet weak var imageView: UIImageView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    @IBAction func chooseImage(_ sender: Any) {

        let imagePickerController = UIImagePickerController()
        imagePickerController.delegate = self

        let actionSheet = UIAlertController(title: "Photo Source", message: "Choose a source", preferredStyle: .actionSheet)

        actionSheet.addAction(UIAlertAction(title: "Camera", style: .default, handler: { (action:UIAlertAction) in

            if UIImagePickerController.isSourceTypeAvailable(.camera) {
                imagePickerController.sourceType = .camera
                self.present(imagePickerController, animated: true, completion: nil)
            }else{
                print("Camera not available")
            }


        }))

        actionSheet.addAction(UIAlertAction(title: "Photo Library", style: .default, handler: { (action:UIAlertAction) in
            imagePickerController.sourceType = .photoLibrary
            self.present(imagePickerController, animated: true, completion: nil)
        }))

        actionSheet.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

        self.present(actionSheet, animated: true, completion: nil)


    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        let image = info[UIImagePickerControllerOriginalImage] as! UIImage

        imageView.image = image

        picker.dismiss(animated: true, completion: nil)
    }

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }





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


}

Answer 1

记得要保存图片，你需要将图片存储为 NSData

      // Code to store image
     let defaults = UserDefaults.standard

   //  To save as data:

  //   From StoryBoard, if you want to save "image" data on the imageView of 
  //   MainStoryBoard, following codes will work.

     let image = UIImagePNGRepresentation(imageView.image!) as NSData? 
    defaults.set(image, forKey: "test")  // saving image into userdefault


     // for retrieving the image 

   if (UserDefaults.standard.object(forKey: "test") as? NSData) != nil {
        let photo = UserDefaults.standard.object(forKey: "test") as! NSData
        img2.image = UIImage(data: photo as Data) // img2 set your imageview on which you want photo to appear

        // Now you can set img2.image
    }

编辑

如何在你的代码中使用

func imagePickerController(_ picker: UIImagePickerController, 
    didFinishPickingMediaWithInfo info: [String : Any]) {
     let defaults = UserDefaults.standard
     let image = info[UIImagePickerControllerOriginalImage] as! UIImage

     imageView.image = image
    let saveImage = UIImagePNGRepresentation(image!) as NSData? 
    defaults.set(saveImage, forKey: "test")  // saving image into userdefault


     picker.dismiss(animated: true, completion: nil)
}

在您看来确实加载使用检索方法 如果图像存在并且是 nsdata 格式，那么只有它会显示保存图像。就是这样。

Answer 2

您可以使用以下功能将图像保存在您的文档目录中

func saveImageDocumentDirectory(tempImage:UIImage){

    let documentsDirectoryURL = try! FileManager().url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    let fileURL = documentsDirectoryURL.appendingPathComponent("ImageName.png")
        do {
            try UIImagePNGRepresentation(tempImage)?.write(to: fileURL)
        } catch {
            print(error)
        }
}

要检索图像，您可以使用

func getImage()->URL?{

    let documentsDirectoryURL = try! FileManager().url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
     let fileURL = documentsDirectoryURL.appendingPathComponent("ImageName.png")

    if FileManager.default.fileExists(atPath: fileURL.path){
        return fileURL
    }else{
        return nil
    }
}

您可以使用任何您喜欢的名称并存储不同名称的图像以存储多个图像。