Custom NSView Drag and Drop images - image

Question

I'm working on an OS X App and, I can't seem to get Drag and Drop to work. I've Googled a lot, but most posts about this subject are at least a few years old and none of them tells me the missing link I have in my thoughts.
Anyway, here is what I'm trying to do. I have an image somewhere on my desktop and I want the ability to drag and drop that into my Custom NSView. The custom view is a child object of a custom NSView named CircularImageView and is layer backed and only shows a circular shaped image on the screen.
Here's the code:
import Cocoa
import MCTools
#objc public protocol DragAndDropCircularImageViewDelegate {
func imageDumped(sender: AnyObject!)
}
#IBDesignable #objc public class DragAndDropCircularImageView: CircularImageView {
// This class provides the Drag And Drop Feature to the CircularImageView Class.
// MARK: New in this class
var highlight: Bool = false
public var delegate: DragAndDropCircularImageViewDelegate?
private func registerForDraggedImages() {
self.registerForDraggedTypes(NSImage.imageTypes())
}
// MARK: CircularImageView Stuff
public override var image: NSImage? {
didSet {
if let newImage = image {
delegate?.imageDumped(self)
}
}
}
public required init?(coder: NSCoder) {
super.init(coder: coder)
self.registerForDraggedImages()
}
public override init(frame frameRect: NSRect) {
super.init(frame: frameRect)
self.registerForDraggedImages()
}
public override func updateLayer() {
super.updateLayer()
if highlight == true {
}
}
// MARK: NS Dragging Destination Protocol
public override func draggingEntered(sender: NSDraggingInfo) -> NSDragOperation {
// When a drag enters our drop zone.
if NSImage.canInitWithPasteboard(sender.draggingPasteboard()) {
if ((sender.draggingSourceOperationMask().rawValue & NSDragOperation.Copy.rawValue) > 0) {
highlight = true
self.needsLayout = true
sender.enumerateDraggingItemsWithOptions(.Concurrent, forView: self, classes: [NSPasteboardItem.self], searchOptions: [NSPasteboardURLReadingContentsConformToTypesKey: self], usingBlock: { (draggingItem, idx, stop) -> Void in
return
})
}
return NSDragOperation.Copy
}
return NSDragOperation.None
}
public override func draggingExited(sender: NSDraggingInfo?) {
// When drag exits our drop zone remove highlight of the drop zone.
println("\(self)draggingExited")
highlight = false
self.needsLayout = true
}
public override func prepareForDragOperation(sender: NSDraggingInfo) -> Bool {
// Update view for hovering drop.
println("\(self)prepareForDragOperation")
highlight = false
self.needsLayout = true
// Can we accept the drop?
return NSImage.canInitWithPasteboard(sender.draggingPasteboard())
}
public override func performDragOperation(sender: NSDraggingInfo) -> Bool {
// Handle the drop data.
println("\(self)performDragOperation \(sender)")
if NSImage.canInitWithPasteboard(sender.draggingPasteboard()) {
self.image = NSImage(pasteboard: sender.draggingPasteboard())
}
return true
}
// MARK: Interface Builder Stuff
}
I have seen some posts that I should be using:
self.registerForDraggedTypes([NSFilenamesPboardType])
instead of:
self.registerForDraggedTypes(NSImage.imageTypes())
But this doesn't seem to work in my case, when I'm using NSFileNamesPboardType I get the following debug message even before any of the NSDraggingDestination protocol messages have been called:
2015-05-07 11:07:19.583 CircularImageViewTest[44809:14389647] -[CircularView.DragAndDropCircularImageView copyWithZone:]: unrecognized selector sent to instance 0x608000166d80
(lldb) p 0x608000166d80
(Int) $R0 = 106102873550208
I don't understand how this works. Somewhere the frameworks try to copyWithZone on an integer? Can anyone explain this to me?
Any help would be appreciated. Thanks in advance.

Answer 1

Ok, the code below works. It was all caused by sender.enumerateDraggingItemsWithOptions in draggingEntered. Something goes wrong in the Apple frameworks when it is called.
import Cocoa
import MCTools
#objc public protocol DragAndDropCircularImageViewDelegate {
func imageDumped(sender: AnyObject!)
}
#IBDesignable #objc public class DragAndDropCircularImageView: CircularImageView {
// This class provides the Drag And Drop Feature to the CircularImageView Class.
// MARK: New in this class
var highlight: Bool = false
public weak var delegate: DragAndDropCircularImageViewDelegate?
private func registerForDraggedImages() {
// self.registerForDraggedTypes(NSImage.imageTypes())
self.registerForDraggedTypes([NSFilenamesPboardType])
}
// MARK: CircularImageView Stuff
public override var image: NSImage? {
didSet {
if let newImage = image {
delegate?.imageDumped(self)
}
}
}
public required init?(coder: NSCoder) {
super.init(coder: coder)
self.registerForDraggedImages()
}
public override init(frame frameRect: NSRect) {
super.init(frame: frameRect)
self.registerForDraggedImages()
}
public override func updateLayer() {
super.updateLayer()
if highlight == true {
}
}
// MARK: NS Dragging Destination Protocol
public override func draggingEntered(sender: NSDraggingInfo) -> NSDragOperation {
// When a drag enters our drop zone.
if NSImage.canInitWithPasteboard(sender.draggingPasteboard()) {
if ((sender.draggingSourceOperationMask().rawValue & NSDragOperation.Copy.rawValue) > 0) {
highlight = true
self.needsLayout = true
}
return NSDragOperation.Copy
}
return NSDragOperation.None
}
public override func draggingExited(sender: NSDraggingInfo?) {
// When drag exits our drop zone remove highlight of the drop zone.
println("\(self)draggingExited")
highlight = false
self.needsLayout = true
}
public override func prepareForDragOperation(sender: NSDraggingInfo) -> Bool {
// Update view for hovering drop.
println("\(self)prepareForDragOperation")
highlight = false
self.needsLayout = true
// Can we accept the drop?
return NSImage.canInitWithPasteboard(sender.draggingPasteboard())
}
public override func performDragOperation(sender: NSDraggingInfo) -> Bool {
// Handle the drop data.
println("\(self)performDragOperation \(sender)")
if NSImage.canInitWithPasteboard(sender.draggingPasteboard()) {
self.image = NSImage(pasteboard: sender.draggingPasteboard())
self.delegate!.imageDumped(self)
}
return true
}
// MARK: Interface Builder Stuff
}