How to use a NSStatusItem as a drag destination?

Question

I'm trying to build an application that allows users to drag files from Finder to the menubar icon for processing. I've made progress in my journey, but I can't seem to summit this hill. I tried subclassing NSView and implementing the drag messages.

@interface CMDroppableView : NSView <NSMenuDelegate>

I wanted to not only accept drag operations, but to provide a NSMenu when the user clicks the icon. I've managed to get the NSMenu to display properly, but the drag functionality remains elusive.

It's my understanding that I needed to register the accepted drag types which I have done here:

-(void)awakeFromNib{
[self registerForDraggedTypes:[NSArray arrayWithObject:NSFilenamesPboardType]];
}

Drag messages:

-(NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender{
    NSLog(@"Drag Enter");
    return NSDragOperationCopy;
}

-(NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender{
    return NSDragOperationCopy;
}

-(void)draggingExited:(id <NSDraggingInfo>)sender{
    NSLog(@"Drag Exit");
}

-(BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender{
     return YES;
}

-(BOOL)performDragOperation:(id <NSDraggingInfo>)sender{
    return YES;
}

Here is the code where the custom view is set:

statusItemView = [[CMDroppableView alloc] init];
[statusItemView retain];
[statusItemView setMenu: statusMenu];

[statusItem setView: statusItemView];

Still nothing. So where have I gone wrong?

Thanks!

Have you implemented the draggingEntered: and performDragOperation: methods? — omz, May 15 '11 at 00:15
I suspect that you just won't be able to do this. Dragging an object to a menu is not a normal UI behaviour, and I think that there are probably system-level restrictions on the interactions that an `NSStatusItem` views can have. I'd be surprised if the view responded to anything other than a mouseUp/Down. — Rob Keniger, May 15 '11 at 01:31
@Rob, that's interesting. How then, do applications like CloudApp enable you to drop files on the statusbar icon? — doomspork, May 15 '11 at 02:10
I can't see anything that he's done wrong, providing that he's using his custom view for the status item's view. :/ — Wevah, May 15 '11 at 03:40
@Wevah, I updated my post to include the code where the custom view is set. Would it be acceptable post all of the code to a pastiebin and link to it? — doomspork, May 15 '11 at 04:04

score 7 · Answer 1 · answered May 15 '11 at 17:21

Through trial and error I stumbled onto the solution. I was registering my acceptable drag types within the awakeFromNib message (as seen in the original question). However, I was not using IB to set this view up so this method was never called. Moving the registration code to the initFromFrame message seemed to fix the problem.

- (id)initWithFrame:(NSRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        ...
        [self registerForDraggedTypes:[NSArray arrayWithObject:NSFilenamesPboardType]];
    }
    return self;
}

Whoops, I didn't read this self-answer before I edited mine. You should accept yours as the right one! (Voted up.) — Wevah, May 15 '11 at 18:23

score 6 · Accepted Answer · edited Jun 20 '20 at 09:12

Edit: D'oh, you're registering the drag types in -awakeFromNib, which won't be called if the view isn't being loaded from a nib. Try registering your drag types in -initWithFrame: instead!

Old answer:

IIRC you need to not set the menu on the status item. What I do is have my custom view manage a menu, and do something like this:

- (void)setMenu:(NSMenu *)menu {
    [menu setDelegate:self];
    [super setMenu:menu];
}

- (void)mouseDown:(NSEvent *)event {
    [statusItem popUpStatusItemMenu:[self menu]]; // or another method that returns a menu
}

- (void)menuWillOpen:(NSMenu *)menu {
    highlight = YES;
    [self setNeedsDisplay:YES];
}

- (void)menuDidClose:(NSMenu *)menu {
    highlight = NO;
    [self setNeedsDisplay:YES];
}

- (void)drawRect:(NSRect)rect {
    NSImage *img = highlight ? [alternateImage copy] : [image copy];
    NSRect bounds = [self bounds];
    [statusItem drawStatusBarBackgroundInRect:bounds withHighlight:highlight];
    
    // rest of drawing code goes here, including drawing img where appropriate
}

in my custom view's implementation. This ensures the menu behavior is identical to the default.

I am setting the NSMenu to my custom view, not the NSStatusItem. More importantly, how do you handle your drag destinations? — doomspork, May 15 '11 at 04:58
Oh, oops. I'll update my answer. Running low on sleep at the moment, though… — Wevah, May 15 '11 at 18:18

How to use a NSStatusItem as a drag destination?

2 Answers2

Old answer: