Drag file from NSTableView to other osx application

Question

I want to drag a file from a NSTableView row to copy it to another application (i.e. Finder). I implemented the first two steps ('Configuring Your Table View', 'Beginning a Drag Operation') of this guide and thought that would do the trick: http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/TableView/Tasks/UsingDragAndDrop.html

However, when I attempt to drag a row, the row text follows my mouse but the file does not copy when released. Here's what I'm sending to my UITableView upon initialization:

#define librarySongDataType @"NSFileContentsPboardType"
- (void)awakeFromNib
{
    [self setDraggingSourceOperationMask:NSUIntegerMax forLocal:YES]; // allow interapplication drags
    [self registerForDraggedTypes:[NSArray arrayWithObject:librarySongDataType] ]; // NSFileContentsPboardType
}

Here's how I'm handling the drag in my NSTableView's data source (an NSArrayController):

- (BOOL)tableView:(NSTableView *)aTableView writeRowsWithIndexes:(NSIndexSet *)rowIndexes toPasteboard:(NSPasteboard *)pboard
{
    NSLog(@"writeRowsWithIndexes");
    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:rowIndexes];
    [pboard setData:data forType:librarySongDataType];
    return YES;
}

To be clear, I'm not trying to drag files into my table view, I'm just trying to drag file(s) out of it.

I think you mean NSTableView. UITableView is only on the iPhone. — d11wtq
Ah, sorry, yes. I meant NSTableView. Thanks for the correction. Edited. — tassock

Yuji Yuji · Accepted Answer · 2010-12-02T11:02:09

Firstly, which document did you refer to when you wrote this line ?

 [self setDraggingSourceOperationMask:NSUIntegerMax forLocal:YES];

This doesn't make sense. Don't use NSUIntegerMax. Use operation masks as defined here. It's written there that NSUIntegerMax stands for everything, but you shouldn't use it; Apple may re-define the bit in the future. You should use NSDragOperationCopy or something specific. If you copied that line from a webpage or a book, you should stop trusting that book/webpage.

Secondly, forLocal: should be NO to pass the data to another application; local here means application local.

Third, instead of just setting the archived data in

 [pboard setData:data forType:librarySongDataType];

Consider making an NSFileWrapper and set it using writeFileWrapper:, see here. That way you can specify the file name to be created in Finder. Otherwise, the system doesn't have any idea what the data represent.

Drag file from NSTableView to other osx application

1 Answers