Re: Dragging NSCells

FROM : James DiPalma
DATE : Fri Jan 24 03:06:48 2003

> From: The Amazing Llama <<email_removed>>
>
> For the record, I'm trying to implement dragging items in a tree view
> around within the tree view, or out to other tree views of the same
> type. I have sub-classed NSMatrix and NSBrowserCell, and hope
> implementing either to accept the drops. NSMatrix, being a view, will
> not be hard; but NSBrowserCell, being a cell, has none of the
> abilities I need.


What is a tree view?

If you mean an NSOutlineView like view, are you having trouble using
NSOutlineView's dragging support? There is probably a sample project on
your machine at

   /Developer/Examples/Cocoa/DragNDropOutlineView

If you mean an NSBrowser like view, I've implemented one and would
start by saying: it probably wasn't worth it and would completely
rewrite NSBrowser instead of subclassing it. Summary of what I did:
   - add drag support to an NSMatrix subclass
   - use this matrix class in an NSBrowser subclass
   - handle drop in NSBrowser (for drags outside of contained matrixes)

Biggest problems:
   - getting mouseDown: to behave correctly for all types of matrixes
   - handling data reloading efficiently and effectively
   - getting selection change notifications for both NSMatrix and
NSBrowser


           -jim
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