Can the parent have less columns than child in NSOutlineView?

Question

I'm trying to implement outline view in my app using NSOutlineView, but in my app the outer layer (parent) should have only one column (Brand) and inner layer (children) should have 5-6 columns (Size,Type,Image, etc.).

Is it possible to achieve, and how to do so if it is?!

Answer 1

Yes, you can have “full-width” cells for “group rows” in a NSOutlineView (or NSTableView).

If you’re using a cell-based outline view, implement outlineView:dataCellForTableColumn:item: in your NSOutlineViewDelegate. Before this method is invoked with any of the existing columns, it will be invoked with a column of nil. For the corresponding rows, return a prototype NSCell, and in your other data source/delegate methods likewise return the corresponding information for a nil “column”. You just need to create a generic NSTextFieldCell for this; no need to style it yourself unless you want to. More information in the documentation or take a look at some Apple sample code.

If you’re using a view-based outline view, implement the equivalent outlineView:viewForTableColumn:item:. Unfortunately the documentation is currently pretty nonexistent, but the corresponding NSTableViewDelegate method is documented, and you can look at this code sample.

The appearance of the full-width item will vary based on the highlight style (selectionHighlightStyle) configured for your outline view; from your description, it sounds like you would want “regular” rather than “source list” behavior.