Swift: Opening a file by drag-and-drop in window

Question

In Swift, how can I build an area in a window of my Mac app where a user can drag-and-drop a folder onto this area, and have my app receive the path of the folder?

In pr

Answer 1

In a custom NSView:

override init(frame frameRect: NSRect)
{
    super.init(frame: frameRect)
    registerForDraggedTypes([kUTTypeFileURL,kUTTypeImage])
}

override func draggingEntered(sender: NSDraggingInfo) -> NSDragOperation
{
    println("dragging entered")
    return NSDragOperation.Copy
}

The catch is, to get it working I had to put that custom view as a leaf and the last view in the storyboard

Answer 2

This worked for me (on a NSWindow subclass):

In awakeFromNib:

registerForDraggedTypes([NSFilenamesPboardType])

Then add the following operations (at least draggingEntered and performDragOperation) to the window (or view):

func draggingEntered(sender: NSDraggingInfo) -> NSDragOperation {
    let sourceDragMask = sender.draggingSourceOperationMask()
    let pboard = sender.draggingPasteboard()!
    if pboard.availableTypeFromArray([NSFilenamesPboardType]) == NSFilenamesPboardType {
        if sourceDragMask.rawValue & NSDragOperation.Generic.rawValue != 0 {
            return NSDragOperation.Generic
        }
    }
    return NSDragOperation.None
}

func draggingUpdated(sender: NSDraggingInfo) -> NSDragOperation {
    return NSDragOperation.Generic
}

func prepareForDragOperation(sender: NSDraggingInfo) -> Bool {
    return true
}

func performDragOperation(sender: NSDraggingInfo) -> Bool {
   // ... perform your magic
   // return true/false depending on success
}

Answer 3

my 2 cents for OSX - swift 5 (and fixed for loading from XIBs/storybord.)

//  Created by ing.conti on 31th jan 2020.
//

import Cocoa

class AnalysisView: NSView {

    override init(frame frameRect: NSRect)
    {
        super.init(frame: frameRect)
        self.registerMyTypes()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        self.registerMyTypes()
    }


    final private func registerMyTypes()
    {
        registerForDraggedTypes(
            [NSPasteboard.PasteboardType.URL,
             NSPasteboard.PasteboardType.fileURL,
             NSPasteboard.PasteboardType.png,
             NSPasteboard.PasteboardType.fileNameType(forPathExtension: "wtf")
        ])
    }



    override func draggingEntered(_ sender: NSDraggingInfo) -> NSDragOperation {
        print("draggingEntered")
        return NSDragOperation.copy
    }

    override func prepareForDragOperation(_ sender: NSDraggingInfo) -> Bool {
        let allow = true // check your types...
        print("prepareForDragOperation")
        return allow
    }

    override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {

        let pasteBoard = sender.draggingPasteboard
        print("performDragOperation")

        if let urls = pasteBoard.readObjects(forClasses: [NSURL.self]) as? [URL]{
            // consume them...
            print(urls)
            return true
        }
        return false
    }
}