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swiftdrag-and-dropuidocument

iOS 11 Drag and Drop UIDocument

Everything is clear about Drag and Drop except how to handle UIDocuments.

this is my (not working) implementation...

For Drag:

func tableView(_ tableView: UITableView, itemsForBeginning session: UIDragSession, at indexPath: IndexPath) -> [UIDragItem] {

    let doc = DataManager.shared.storage[indexPath.row] // the UIDocument to drag
    let itemProv = NSItemProvider()
    itemProv.registerFileRepresentation(forTypeIdentifier: "com.mybundle.myapp.myextension",
                                        fileOptions: [.openInPlace],
                                        visibility: .all) { completionHandler in

        completionHandler(doc.fileURL, true, nil)
        return nil
    }

    // DragItem
    let item = UIDragItem(itemProvider: itemProv)

    return [item]
}

For drop:

func tableView(_ tableView: UITableView, performDropWith coordinator: UITableViewDropCoordinator) {

    for item in coordinator.session.items {
        item.itemProvider.loadFileRepresentation(forTypeIdentifier: "com.mybundle.myapp.myextension", completionHandler: { (url, error) in

            if let docUrlOk = url {
                debugPrint(urlOk.absoluteString)
                DataManager.shared.load(docUrlOk)
            }
        })
    }
}

And the update method:

func tableView(_ tableView: UITableView, dropSessionDidUpdate session: UIDropSession, withDestinationIndexPath destinationIndexPath: IndexPath?) -> UITableViewDropProposal {

    if tableView.hasActiveDrag {
        if session.items.count > 1 {
            return UITableViewDropProposal(operation: .cancel)
        } else {
            return UITableViewDropProposal(operation: .move, intent: .insertAtDestinationIndexPath)
        }
    } else {
        return UITableViewDropProposal(operation: .copy, intent: .insertAtDestinationIndexPath)
    }
}

Thank you so much

Solution

  • After a lot of talk with an Apple engineer I found a "semi" solution. The posted code in the question is correct, but to drag a proprietary file from your App to the Files App you have to insert the following values in the Target -> Info -> Exported UTIs field enter image description here

    BUT if you drag your proprietary file from Files App back to your App there is a bug in UIKit that prevents it from working properly... the engineer told me to wait for iOS 11.3 or iOS 12, we'll see