On 19/02/2013, at 11:09 AM, Chuck Soper <chu...@veladg.com> wrote: > Does anyone know the steps to allow custom dragging of a table column to > another table? Is this possible? If I was dealing with an NSView subclass, > I think this would be straightforward. I want to show the entire column > (header + row) when dragging. I believe that the dragging implementation > could go in my NSTableHeaderCell subclass, but I'm not sure how to get > started.
It's definitely possible, but you'll have to do a bit of subclassing. I suspect you're going to need to subclass the overall NSTableView so that you can receive a private drag type and do the necessary graphics work as part of NSDraggingDestination. There are two parts to a drag - the drag source and the drag destination. The source can be your custom table header cell, but the destination is probably going to have to be a subclass of the table view itself. The two parts can be programmed fairly independently, once you've settled on how they are going to communicate in terms of the column data you pass from to the other. Having subclassed your table header cell, kicking off the drag shouldn't be too hard - just handle the mouseDown or mouseDragged and capture an image of the column as the drag image. NSView's method for capturing part of a view to a bitmap rep is invaluable here. Declare a private drag type and use whatever data makes sense to pass the column content through the drag pasteboard mechanism - you might not need to actually transfer any data, you could just store enough info in shared variables (e.g. just make a note of the source column somewhere) that your custom table class can access - as it's all private there's no need to consider dragging to other apps or supporting standard data formats. The hardest part as I see it is in receiving the drag. Your custom table class will register for the private drag type, and implement NSDraggingDestination methods to do whatever is needed to provide feedback and validation of the drag. You will need for example to highlight the place where the column can be dropped, and maybe animate moving other columns apart to "make room". You'll want to pass anything else up to super's implementation to continue supporting all the standard dragging that the table can handle. On a drop, you just need to remove the column from the source, use the private data to recreate it at the destination and insert it into the table view. --Graham _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
