Swift - UIImagePickerController - how to use it?

Question

I am trying hard to understand how this works, but it\'s pretty hard for me. =) I have 1 view, there is one button and one small ImageView area for preview. The button trigg

Answer 1

You're grabbing a UIImage named UIImagePickerControllerOriginalImage and there exists no such image. You're meant to grab the UIImage with the key UIImagePickerControllerOriginalImage from the editingInfo dictionary:

let tempImage = editingInfo[UIImagePickerControllerOriginalImage] as! UIImage

Answer 2

Try this:

func imagePickerController(picker: UIImagePickerController!, didFinishPickingMediaWithInfo info:NSDictionary!) {
    let tempImage = info[UIImagePickerControllerOriginalImage] as! UIImage
    imagePreview.image  = tempImage

or you can also use ? in place of !.

Answer 3

import MobileCoreServices

class SecondViewController: UIViewController,UINavigationControllerDelegate, UIImagePickerControllerDelegate {

   @IBOutlet var img:UIImageView!=nil

   override func viewDidLoad() {
        super.viewDidLoad()
   }

   override func didReceiveMemoryWarning() 
   {
       super.didReceiveMemoryWarning()

   }

   @IBAction func buttonTapped(AnyObject)
   {
     if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.PhotoLibrary){
            println("Button capture")
            var imag = UIImagePickerController()
            imag.delegate = self
            imag.sourceType = UIImagePickerControllerSourceType.PhotoLibrary;
            //imag.mediaTypes = [kUTTypeImage];
            imag.allowsEditing = false
            self.presentViewController(imag, animated: true, completion: nil)
        }
   }

   func imagePickerController(picker: UIImagePickerController!, didFinishPickingImage image: UIImage!, editingInfo: NSDictionary!) {
        let selectedImage : UIImage = image
       //var tempImage:UIImage = editingInfo[UIImagePickerControllerOriginalImage] as UIImage
        img.image=selectedImage
        self.dismissViewControllerAnimated(true, completion: nil)    
   }
 }

Answer 4

Since swift 4.2 and xcode 10 the func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) change a bit.

at the function header the infoKey-Section changes from

didFinishPickingMediaWithInfo info: [String : Any] to

didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]

To get the originalImage you now have to call:

let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage or

let image = info[.originalImage] as? UIImage

find other infoKeys here (editedImage, imageURL and more...)

Answer 5

Details

• Xcode 11.4.1 (11E503a), Swift 5.2

More

How to build own photo picker

Solution

import UIKit
import AVFoundation
import Photos

protocol ImagePickerDelegate: class {
    func imagePicker(_ imagePicker: ImagePicker, grantedAccess: Bool,
                     to sourceType: UIImagePickerController.SourceType)
    func imagePicker(_ imagePicker: ImagePicker, didSelect image: UIImage)
    func cancelButtonDidClick(on imageView: ImagePicker)
}

class ImagePicker: NSObject {

    private weak var controller: UIImagePickerController?
    weak var delegate: ImagePickerDelegate? = nil

    func dismiss() { controller?.dismiss(animated: true, completion: nil) }
    func present(parent viewController: UIViewController, sourceType: UIImagePickerController.SourceType) {
        let controller = UIImagePickerController()
        controller.delegate = self
        controller.sourceType = sourceType
        self.controller = controller
        DispatchQueue.main.async {
            viewController.present(controller, animated: true, completion: nil)
        }
    }
}

// MARK: Get access to camera or photo library

extension ImagePicker {

    private func showAlert(targetName: String, completion: ((Bool) -> Void)?) {
        DispatchQueue.main.async { [weak self] in
            guard let self = self else { return }
            let alertVC = UIAlertController(title: "Access to the \(targetName)",
                                            message: "Please provide access to your \(targetName)",
                                            preferredStyle: .alert)
            alertVC.addAction(UIAlertAction(title: "Settings", style: .default, handler: { action in
                guard   let settingsUrl = URL(string: UIApplication.openSettingsURLString),
                        UIApplication.shared.canOpenURL(settingsUrl) else { completion?(false); return }
                UIApplication.shared.open(settingsUrl, options: [:]) { [weak self] _ in
                    self?.showAlert(targetName: targetName, completion: completion)
                }
            }))
            alertVC.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { _ in completion?(false) }))
            UIApplication.shared.windows.filter { $0.isKeyWindow }.first?
                .rootViewController?.present(alertVC, animated: true, completion: nil)
        }
    }

    func cameraAsscessRequest() {
        if delegate == nil { return }
        let source = UIImagePickerController.SourceType.camera
        if AVCaptureDevice.authorizationStatus(for: .video) ==  .authorized {
            delegate?.imagePicker(self, grantedAccess: true, to: source)
        } else {
            AVCaptureDevice.requestAccess(for: .video) { [weak self] granted in
                guard let self = self else { return }
                if granted {
                    self.delegate?.imagePicker(self, grantedAccess: granted, to: source)
                } else {
                    self.showAlert(targetName: "camera") { self.delegate?.imagePicker(self, grantedAccess: $0, to: source) }
                }
            }
        }
    }

    func photoGalleryAsscessRequest() {
        PHPhotoLibrary.requestAuthorization { [weak self] result in
            guard let self = self else { return }
            let source = UIImagePickerController.SourceType.photoLibrary
            if result == .authorized {
                DispatchQueue.main.async { [weak self] in
                    guard let self = self else { return }
                    self.delegate?.imagePicker(self, grantedAccess: result == .authorized, to: source)
                }
            } else {
                self.showAlert(targetName: "photo gallery") { self.delegate?.imagePicker(self, grantedAccess: $0, to: source) }
            }
        }
    }
}

// MARK: UINavigationControllerDelegate

extension ImagePicker: UINavigationControllerDelegate { }

// MARK: UIImagePickerControllerDelegate

extension ImagePicker: UIImagePickerControllerDelegate {

    func imagePickerController(_ picker: UIImagePickerController,
                               didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let image = info[.editedImage] as? UIImage {
            delegate?.imagePicker(self, didSelect: image)
            return
        }

        if let image = info[.originalImage] as? UIImage {
            delegate?.imagePicker(self, didSelect: image)
        } else {
            print("Other source")
        }
    }

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        delegate?.cancelButtonDidClick(on: self)
    }
}

Full Usage

Info.plist

 <key>NSPhotoLibraryUsageDescription</key>
 <string>bla-bla-bla</string>
 <key>NSCameraUsageDescription</key>
 <string>bla-bla-bla</string>

ViewController (do not forget to paste solution code)

import UIKit

class ViewController: UIViewController {

    private weak var imageView: UIImageView!
    private lazy var imagePicker: ImagePicker = {
        let imagePicker = ImagePicker()
        imagePicker.delegate = self
        return imagePicker
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "camera", style: .plain, target: self,
                                                           action: #selector(cameraButtonTapped))
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "photo", style: .plain, target: self,
                                                           action: #selector(photoButtonTapped))

        let imageView = UIImageView(frame: CGRect(x: 40, y: 80, width: 200, height: 200))
        imageView.backgroundColor = .lightGray
        view.addSubview(imageView)
        self.imageView = imageView
    }

    @objc func photoButtonTapped(_ sender: UIButton) { imagePicker.photoGalleryAsscessRequest() }
    @objc func cameraButtonTapped(_ sender: UIButton) { imagePicker.cameraAsscessRequest() }
}

// MARK: ImagePickerDelegate

extension ViewController: ImagePickerDelegate {

    func imagePicker(_ imagePicker: ImagePicker, didSelect image: UIImage) {
        imageView.image = image
        imagePicker.dismiss()
    }

    func cancelButtonDidClick(on imageView: ImagePicker) { imagePicker.dismiss() }
    func imagePicker(_ imagePicker: ImagePicker, grantedAccess: Bool,
                     to sourceType: UIImagePickerController.SourceType) {
        guard grantedAccess else { return }
        imagePicker.present(parent: self, sourceType: sourceType)
    }
}

Images

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