How to display show/Hide button in highlight regular mode of NSOutlineView?

Question

How to display show/Hide button in highlight regular mode of NSOutlineView?

I have a grop item at the top of NSOutlineview. I try to display show/hide button in that group item, but I can't find any method to do it. The source list mode can display it but regular mode doesn't.

Is it possible to display show/hide button in highlight regular mode of NSOutlineview?

thanks for helping

Answer 1

This behavior is specific to the source list appearance. There is no public API for getting around this, as it's an intentional enforcement (on Apple's part) of standardized appearances. You could dig around in the headers to look for a way to "hotwire" things, but use of private API bars you from distributing your app through the App Store.

The easier (non-private-API-using) route is to create your own cell view with a borderless button with show/hide title. Use a mouse tracking area (see NSTrackingArea ) on the cell view (the superview of your button) to set the button's alpha (via its animator) to fade the button in/out on mouse in/out. Your button would tell the outline view to expand/collapse its cell view's represented item (the easiest way would be to define an outlet to the button via your custom NSView cell view class and configure the button's target/action when the cell view is created for the item).