UICloudSharingController shows infinite activity indicatory in Xcode 11

Question

I have the following code to import the UICloudSharingController into swift UI but when integrated the first time up it just shows an activity indicator that never stops and then the second time it is presented (via .sheet), there is no activity indicator. The first time up I can see the close button to the top right corder with activity indicator. Any feedback would be appreciated.

struct CloudSharingController: UIViewControllerRepresentable {
    typealias UIViewControllerType = UICloudSharingController

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    class Coordinator: NSObject, UICloudSharingControllerDelegate {
        func cloudSharingController(_ csc: UICloudSharingController, failedToSaveShareWithError error: Error) {
            print("asdf")

        }

        func itemTitle(for csc: UICloudSharingController) -> String? {
            return "item title for sharing TTT"
        }

        var parent: CloudSharingController

        init(_ cloudSharingController: CloudSharingController) {
            self.parent = cloudSharingController
        }
    }


    var share: CKShare? = nil
    var container: CKContainer = CKContainer.default()

    var firsTimeBlock: ((UICloudSharingController, @escaping (CKShare?, CKContainer?, Error?) -> Void) -> Void)? = nil

    func makeUIViewController(context: UIViewControllerRepresentableContext<CloudSharingController>) -> CloudSharingController.UIViewControllerType {

        let result: UICloudSharingController!
        if let validFirstBlock = firsTimeBlock {
            return UICloudSharingController(preparationHandler: validFirstBlock)
        } else if let validShare = self.share {
            return UICloudSharingController(share: validShare,
                                            container: container)
        } else {
            fatalError()
        }
        result.availablePermissions = [.allowReadWrite]
//        result.popoverPresentationController?.sourceView = AccountsView
        result.delegate = context.coordinator

        return result
    }

    func updateUIViewController(_ uiViewController: CloudSharingController.UIViewControllerType, context: UIViewControllerRepresentableContext<CloudSharingController>) {

    }
}

Answer 1

There is now a new Apple demo project that uses the UICloudSharingController.

If no share record exists, the UICloudSharingController is initialized with a preparationHandler:

private func newSharingController(unsharedPhoto: Photo, persistenceController: PersistenceController) -> UICloudSharingController {
    return UICloudSharingController { (_, completion: @escaping (CKShare?, CKContainer?, Error?) -> Void) in
        self.persistentContainer.share([unsharedPhoto], to: nil) { objectIDs, share, container, error in
            if let share = share {
                self.configure(share: share)
            }
            completion(share, container, error)
        }
    }
}  

where the persistenceController is

class PersistenceController: NSObject, ObservableObject {
// …
}  

The UICloudSharingController is presented using

func presentCloudSharingController(photo: Photo) {
    /**
     Grab the share if the photo is already shared.
     */
    var photoShare: CKShare?
    if let shareSet = try? persistentContainer.fetchShares(matching: [photo.objectID]),
       let (_, share) = shareSet.first {
        photoShare = share
    }

    let sharingController: UICloudSharingController
    if photoShare == nil {
        sharingController = newSharingController(unsharedPhoto: photo, persistenceController: self)
    } else {
        sharingController = UICloudSharingController(share: photoShare!, container: cloudKitContainer)
    }
    sharingController.delegate = self
    /**
     Setting the presentation style to .formSheet so there's no need to specify sourceView, sourceItem, or sourceRect.
     */
    if let viewController = rootViewController {
        sharingController.modalPresentationStyle = .formSheet
        viewController.present(sharingController, animated: true)
    }
}  

The last lines in this code show that the controller is not presented using SwiftUI, but the UIKit.

Obviously it is currently not possible to initialize the UICloudSharingController with preparationHandler in SwiftUI.

Answer 2

I found a work around which could be found in here:

https://gist.github.com/arashkashi/bcffde1e35c7e406de52d9dff0127d41

The solution in brief includes a view controller wrapper which contains an instance of UICloudSharingController as a child view controller.

UICloudSharingController has two initialized one when there is no CKShare and another one where you already have a CKShare pushed to the CloudKit. I observed that the former initializer gives a never ending activity indicator. So What I did I manually pushed the share with no participants and then provided the empty share to the second initialized of UICloudSharingController.

This is the reason why the wrapper controller should have this line:

var share: CKShare? = nil