CODEWITHSUNDEEP
iosswiftdrag-and-drop
Natasha
Natasha

Reputation: 6893

How to get actual data/content provided by NSItemProvider rather than the type

I am new to iOS 11 Drag and Drop feature. I know how to load a particular type of object when dropped in view that can accept that type of object. However, before calling the loadObject(ofClass:completionHandler:), I want to know the values that the dropped item is holding.

In my dropInteraction(_:performDrop:) delegate method, when I try to get the description of the itemProvider object, I only get the type-

func dropInteraction(_ interaction: UIDropInteraction, performDrop session: UIDropSession) {

        if let itemProvider = session.items.last?.itemProvider{
            print("item provider \(itemProvider.description)")
        }
}

As I was dropping an image from safari, the above code printed- 

item provider <UIItemProvider: 0x600000c43640> {types = (
    "public.jpeg",
    "public.url"
)}

Here I can't see the url value. If I want to get the url value, I have to do-

func dropInteraction(_ interaction: UIDropInteraction, performDrop session: UIDropSession) {

    session.items.last?.itemProvider.loadObject(ofClass: URL.self, completionHandler: { itemProvider, err in
      if let urlItemProvider = itemProvider{
          print("url = \(urlItemProvider.absoluteString)")
      }
  })
}

Basically whenever an image is dropped, I want to save its associated url and the details about the image in a custom class before I attempt to load it. Any help will be appreciated.

Upvotes: 5

Views: 5546

Answers (1)

ph1lb4
ph1lb4

Reputation: 2132

I found that loading two objects with the loadObject method always resulted in an error. However, duplicating the itemProvider with the .copy() method worked.

For example:

let provider = item.dragItem.itemProvider.copy() as! NSItemProvider
item.dragItem.itemProvider.loadObject(ofClass: URL.self, completionHandler: { (url, _) in
    provider.loadObject(ofClass: String.self) { (data, error) in
    }
})

Upvotes: 2

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