How to convert 'UIImagePickerController.InfoKey.originalImage' into 'UIImage' - swift

Question

I'm developping an iOS phone app and I want to take a picture and store it in the app.
I am able to take the picture using a UIImagePickerController but I can't store it in my database. I'm using CoreData to store data in this app but for the picture, it seems that it is easier to store the picture in a folder and store the file path in Coredata. The issue is that I can get the picture i've took with the camera but I can't get the PNG data to store it in my folder.
func takePhoto(){
//Take the picture with the camera
imagePickerController = UIImagePickerController()
imagePickerController.delegate = self
if !UIImagePickerController.isSourceTypeAvailable(.camera){
let alertController = UIAlertController.init(title: nil, message: "Camera is not available", preferredStyle: .alert)
let okAction = UIAlertAction.init(title: "Alright", style: .default, handler: {(alert: UIAlertAction!) in })
alertController.addAction(okAction)
self.present(alertController, animated: true, completion: nil)
}
else{ imagePickerController.sourceType = .camera }
present(imagePickerController, animated: true, completion: nil)
//Store the picture in an app folder
let fileManager = FileManager.default
let imagePath = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("image")
let picture = UIImagePickerController.InfoKey.originalImage as? UIImage
let data = picture?.pngData()
fileManager.createFile(atPath: imagePath as String, contents: data, attributes: nil)
//Store the file path in CoreData
let image = Image(context: self.persistenceManager.context)
image.pathName = imagePath
self.persistenceManager.saveContext()
}
The problem is when I try to get the png data. I need a UIImage to use .pngData() but when I try to convert my picture object into UIImage from UIImagePickerController.InfoKey.originalKey I have the following warning message:
"Cast from 'UIImagePickerController.InfoKey' to unrelated type 'UIImage' always fails".
Also, I don't understand why I need to convert it because I found in the AppleDevelopper website that: "The value for this key is a UIImage object." (the key is "static let originalImage: UIImagePickerController.InfoKey" )
I've also tried to let my picture object as an UIImagePickerController.InfoKey object without converting it into an UIImage object but in this case I have the following error message:
"Value of type 'UIImagePickerController.InfoKey' has no member 'pngData' "
and the method UIImagePNGRepresentation() is not working because the expected argument type is also 'UIImage'

Answer 1

UIImagePickerController.InfoKey.originalImage is a String... it's a key, not the actual image.
You should use the UIImagePickerControllerDelegate, like so
extension ViewController: UIImagePickerControllerDelegate {
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let image = info[.originalImage] as? UIImage
}
}
You see, the information from the UIPickerController is passed as a dictionary with the type [UIImagePickerController.InfoKey : Any], UIImagePicker.InfoKey contains all of the Keys that are used in this dictionary, so you use these to access the values.
EDIT:
So your takePhoto function only needs to display the picker, then handle the response later in the delegate method:
func takePhoto(){
//Take the picture with the camera
imagePickerController = UIImagePickerController()
imagePickerController.delegate = self
if !UIImagePickerController.isSourceTypeAvailable(.camera){
let alertController = UIAlertController.init(title: nil, message: "Camera is not available", preferredStyle: .alert)
let okAction = UIAlertAction.init(title: "Alright", style: .default, handler: {(alert: UIAlertAction!) in })
alertController.addAction(okAction)
self.present(alertController, animated: true, completion: nil)
}
else{ imagePickerController.sourceType = .camera }
present(imagePickerController, animated: true, completion: nil)
}
Then in your delegate you can work with the selected image
extension ViewController: UIImagePickerControllerDelegate {
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let fileManager = FileManager.default
let imagePath = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("image")
let picture = info[.originalImage] as? UIImage
let data = picture?.pngData()
fileManager.createFile(atPath: imagePath as String, contents: data, attributes: nil)
//Store the file path in CoreData
let image = Image(context: self.persistenceManager.context)
image.pathName = imagePath
self.persistenceManager.saveContext()
}
}

Answer 2

As #Scriptabel has stated,
you'll need to use this delegate and access/save your image inside the function.
Class VC: UIViewController, UIImagePickerControllerDelegate {
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let picture = info[UIImagePickerController.InfoKey.originalImage] as! UIImage
let data = picture.pngData()
//Store the picture in an app folder
let fileManager = FileManager.default
let imagePath = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("image")
fileManager.createFile(atPath: imagePath as String, contents: data, attributes: nil)
//Store the file path in CoreData
let image = Image(context: self.persistenceManager.context)
image.pathName = imagePath
self.persistenceManager.saveContext()
}
}