问题
On the surface I thought that this had to be a delegate issue, but after asking for the delegate the right one was returned.
I created an ImagePicker class to handle all the UIImagePickerController stuff. Every thing works until the delegate methods need to be called. After I pick a photo, the imagePicker dismisses, but the didFinishPickingMediaWithInfo method never gets called. Please help! Thanks :)
func selectPhoto() {
imagePicker.delegate = self //Delegate gets set here
let photoAsk = UIAlertController.init( //Ask user if they want to take picture or choose one
title: "Edit Profile Picture",
message: nil,
preferredStyle: .alert)
let cameraAction = UIAlertAction.init(
title: "Take Photo",
style: .default) { (UIAlertAction) in
if (UIImagePickerController.isSourceTypeAvailable(.camera)) {
self.imagePicker.sourceType = .camera
UIApplication.topViewController()!.present(self.imagePicker, animated: true, completion:nil)
} else {
print("Cannot access camera in simulator.")
return
}
}
let photoLibraryAction = UIAlertAction.init(
title: "Photo Library",
style: .default) { (UIAlertAction) in
self.imagePicker.sourceType = .photoLibrary
UIApplication.topViewController()!.present(self.imagePicker, animated: true, completion:nil)
print("UIImagePickerDelegate: \(self.imagePicker.delegate.debugDescription)") // <--THIS PRINTS OUT "AppName.ImagePicker: 0x145d7bdf0>", and the class name is ImagePicker
}
let cancelAction = UIAlertAction.init(
title: "Cancel",
style: .cancel) { (UIAlertAction) in return }
photoAsk.addAction(cameraAction)
photoAsk.addAction(photoLibraryAction)
photoAsk.addAction(cancelAction)
imagePicker.mediaTypes = [kUTTypeImage as String]
UIApplication.topViewController()?.present(photoAsk, animated: true, completion: nil)
}
}
This never gets called:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
print("Image picked.") //NEVER PRINTS
}
回答1:
Details
- Xcode 9.2, Swift 4
- Xcode 10.2.1 (10E1001), Swift 5
Solution
extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
dismiss(animated: true, completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
print("\(info)")
if let image = info[.originalImage] as? UIImage {
imageView?.image = image
dismiss(animated: true, completion: nil)
}
}
}
Usage
let imagePickerController = UIImagePickerController()
imagePickerController.allowsEditing = false
imagePickerController.sourceType = .photoLibrary
imagePickerController.delegate = self
present(imagePickerController, animated: true, completion: nil)
Full sample
Do not forget to add the solution code here (look above)
import UIKit
class ViewController: UIViewController {
private weak var imageView: UIImageView?
override func viewDidLoad() {
super.viewDidLoad()
let stackView = UIStackView(frame: .zero)
stackView.axis = .vertical
stackView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(stackView)
stackView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
stackView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
let imageView = UIImageView()
imageView.contentMode = .scaleAspectFit
imageView.translatesAutoresizingMaskIntoConstraints = false
stackView.addArrangedSubview(imageView)
imageView.widthAnchor.constraint(equalToConstant: 200).isActive = true
imageView.heightAnchor.constraint(equalToConstant: 200).isActive = true
self.imageView = imageView
let button = UIButton(frame: .zero)
button.setTitle("Button", for: .normal)
button.setTitleColor(.blue, for: .normal)
button.addTarget(self, action: #selector(showImages), for: .touchUpInside)
stackView.addArrangedSubview(button)
}
@IBAction func showImages(_ sender: AnyObject) {
let imagePickerController = UIImagePickerController()
imagePickerController.allowsEditing = false
imagePickerController.sourceType = .photoLibrary
imagePickerController.delegate = self
present(imagePickerController, animated: true, completion: nil)
}
}
回答2:
I had to copy the method names straight from the delegate. For some reason the auto-complete has the method headers wrong.
public func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {
//save image
//display image
}
self.dismiss(animated: true, completion: nil)
}
public func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
self.dismiss(animated: true, completion: nil)
}
UPDATE SWIFT 5:
public func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
if let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage {
//save image
//display image
}
self.dismiss(animated: true, completion: nil)
}
回答3:
I found that the delegate code had to be within an active UIViewController.
I originally tried to have my code in a separate file, as as NSObject with the correct delegate protocols declared, like this:
class PhotoPicker: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
But that never called the delegate methods.
Taking the exact same code and placing it within the UIViewController I was calling it from made it work.
It looks like the best solution is to create a pop-up type view, and have its ViewController keep the code.
回答4:
I also faced this issue and solved it by using below solution. Set picker's delegate after present completion.
controller.present(picker, animated: true, completion: {
self.picker.delegate = self
})
Hope this will work for you!!
回答5:
Yo have to make sure that UIImagePickerController was not released before delegate called.
I created an ImagePicker class to handle all the UIImagePickerController stuff.
I created similar class, but
func onButtonDidTap(sender: UIButton) {
.....
let picker = VLImagePickerController()
picker.show(fromSender: sender, handler: { (image: UIImage?) -> (Void) in
if (image != nil) {
self.setImage(image!)
}
})
....
}
did not work for me. 'picker' was released before 'handler' could be called.
I created permanent reference, and it worked:
let picker = VLImagePickerController()
func onButtonDidTap(sender: UIButton) {
.....
//let picker = VLImagePickerController()
picker.show(fromSender: sender, handler: { (image: UIImage?) -> (Void) in
if (image != nil) {
self.setImage(image!)
}
})
....
}
回答6:
This code works, (although, it redisplays over and over because it displays the picker in viewWillAppear, this is just to keep code small). I would look at what is different from this. It could have to do with your top view controller? Why not just display the picker from a view controller rather than go to application's top view controller? Also, once you get the delegate callback, you need to dismiss the view controller.
import UIKit
import MobileCoreServices
class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
let imagePicker = UIImagePickerController()
override func viewDidLoad() {
super.viewDidLoad()
imagePicker.mediaTypes = [kUTTypeImage as String]
imagePicker.delegate = self
}
override func viewDidAppear(_ animated: Bool) { // keeps reopening, do not this in your code.
present(imagePicker, animated: true, completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
imagePicker.dismiss(animated: true, completion: nil)
}
}
回答7:
I voted this one up because I was missing the UINavgationControllerDelegate declaration and this comment helped.
imagePickerController wasn't being called.
来源：https://stackoverflow.com/questions/39682915/uiimagepickercontroller-delegate-not-called-swift-3