Search code examples
macoscocoadrag-and-dropnsviewnsviewcontroller

How to call registerForDraggedTypes in NSViewController?


I have a MainViewController with a splitview in it. Next I have two viewcontroller to control each of the views in the splitview. I want to be able to drag and drop a file in one of those views.

But I can't seem to get the dragging to work? There's no "plus-sign" on the file when dragged to the view and dropping it doesn't do anything either.

What am I doing wrong?

First here's MainViewController.m

fileViewController = [[FileViewController alloc] initWithNibName:@"FileViewController" bundle:nil];
terminalViewController = [[TerminalViewController alloc] initWithNibName:@"TerminalViewController" bundle:nil];

[splitView replaceSubview:[[splitView subviews] objectAtIndex:0] with:[fileViewController view]];
[splitView replaceSubview:[[splitView subviews] objectAtIndex:1] with:[terminalViewController view]];

Next, my code to handle the dragging in the FileViewController

@dynamic isHighlighted;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        NSLog(@"registering");
        [self.view registerForDraggedTypes:[NSArray arrayWithObjects: NSFilenamesPboardType, nil]];
    }



    return self;
}

- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender {
    NSLog(@"[%@ %@]", NSStringFromClass([self class]), NSStringFromSelector(_cmd));

    NSPasteboard *pboard = [sender draggingPasteboard];

    if ([[pboard types] containsObject:NSFilenamesPboardType]) {

        NSArray *paths = [pboard propertyListForType:NSFilenamesPboardType];
        for (NSString *path in paths) {
            NSError *error = nil;
            NSString *utiType = [[NSWorkspace sharedWorkspace]
                                 typeOfFile:path error:&error];
            if (![[NSWorkspace sharedWorkspace] 
                  type:utiType conformsToType:(id)kUTTypeFolder]) {

                [self setHighlighted:NO];
                return NSDragOperationNone;
            }
        }
    }
    [self setHighlighted:YES];
    return NSDragOperationEvery;
}

- (void)draggingExited:(id <NSDraggingInfo>)sender {
    [self setHighlighted:NO];
}


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

- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
    [self setHighlighted:NO];
    return YES;
}

- (void)concludeDragOperation:(id )sender {
    [self.view setNeedsDisplay:YES];
} // end concludeDragOperation

- (BOOL)isHighlighted {
    return isHighlighted;
}

- (void)setHighlighted:(BOOL)value {
    isHighlighted = value;
    [self.view setNeedsDisplay:YES];
}

- (void)drawRect:(NSRect)frame {
    [self.view drawRect:frame];
    if (isHighlighted) {
        [NSBezierPath setDefaultLineWidth:6.0];
        [[NSColor keyboardFocusIndicatorColor] set];
        [NSBezierPath strokeRect:frame];
    }
}

Solution

  • I didn't seem to fix it, and because no one gave me any answers, I fixed it by making an NSView subclass and adding it to my viewcontroller like this.

    - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
    {
        self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
        if (self) {
            draggable = [[DragView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
            [[self view] addSubview:draggable];
        }
    
        return self;
    }