NSTabView blocking file-drop events active on underlying Window. - objective-c

Question

I have successfully implemented a file-drop functionality in my app. The Application window has a few NSTabView objects where dropping on them does not work. Anywhere else in the window the file-drop works fine.
I have tried to make the app delegate a delegate for the NSTabView, but this did not help.
Anyone have a setup for the NSTabView not to filter out the drop-actions so the whole window can be transparent to the file-drop actions ?

Answer 1

For a more generic solution than olekeh's I made it IB friendly so you can hook it up to any object that complies with the NSDraggingDestination protocol.
#import <Cocoa/Cocoa.h>
#interface DropFilesView : NSView
#property (nullable, assign) IBOutlet id<NSDraggingDestination> dropDelegate;
#end
#implementation DropFilesView
- (void)drawRect:(NSRect)dirtyRect {
[super drawRect:dirtyRect];
}
-(void) awakeFromNib {
[self registerForDraggedTypes:
[NSArray arrayWithObjects:NSFilenamesPboardType,
(NSString *)kPasteboardTypeFileURLPromise,kUTTypeData, NSURLPboardType, nil]]; //kUTTypeData
[super awakeFromNib];
}
-(NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender{
return [self.dropDelegate draggingEntered:sender];
}
- (BOOL)performDragOperation:(id < NSDraggingInfo >)sender {
return [self.dropDelegate performDragOperation:sender];
}
#end

Answer 2

I found the solution to this !! - I am posting it here for others who might need.
The NSTabView object has for each of its tabs an NSTabViwItem.
Under each of those, there is a regular NSView - that I subclassed with the following code: - The code assumes that you already have "draggingEntered" and "performDragOperation" in your AppDelegate as this class just forwards these messages to the app delegate. You will also need to put the declarations for those methods in you AppDelegate.h
// DropFilesView.h
#import <Cocoa/Cocoa.h>
#import "AppDelegate.h"
#interface DropFilesView : NSView
#end
and the implementation:
// DropFilesView.m
#import "DropFilesView.h"
#implementation DropFilesView
- (void)drawRect:(NSRect)dirtyRect {
[super drawRect:dirtyRect];
}
-(void) awakeFromNib {
[self registerForDraggedTypes:
[NSArray arrayWithObjects:NSFilenamesPboardType,
(NSString *)kPasteboardTypeFileURLPromise,kUTTypeData, NSURLPboardType, nil]]; //kUTTypeData
[super awakeFromNib];
}
-(NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender
{
AppDelegate* del = [AppDelegate sharedAppDelegate];
return [del draggingEntered:sender];
}
- (BOOL)performDragOperation:(id < NSDraggingInfo >)sender {
AppDelegate* del = [AppDelegate sharedAppDelegate];
return [del performDragOperation:sender];
}
#end
In Interfacebuilder, I set the new class for all the NSView objects covering areas where drop does not work, to this new one.
A similar approach can be used for NSImageView and the WebView classes. However, for the last one, do not use [super awakeFromNib] to prevent the default drag-and drop handling for the web view object.