[Using Xcode 4.2 on Snow Leopard. OSX, not iOS]
In IB, I created an outline view, and set up a view controller to be it's data source. When I expand/collapse a row, the 1st column resizes for indentation. When I double-click the column header resizers, the columns resize to fit their current contents.
How can I invoke that size-to-fit behavior on expand/collapse? I can use the outlineViewItemDidExpand: and outlineViewItemDidCollapse: to call a resizing method, but I can't find what method does the default size-to-fit. I'd rather not reimplement it if it's something Apple makes available.
Can't see any way to invoke it, but it's probably just as well. While experimenting, I saw the fact that for larger tables (over 100), the default behavior doesn't always find the largest. I guess I'll just have to code up a real size-to-fit. :(