File browser-like element in Mac OS programming of Xcode

Question

Sorry that my title is not clear enough. What I wanted to ask is based on a screen capture:

I want to make an app like this. But there are two elements I do not know what the classes are: A and B (C and D are NSSplitView. I just knew).

Could any one just tell me what ducuments to follow to create UIs like the appearance of A and B? Thank you!

Answer 1

Create A UI in NSOutlineView is the way to display hierarchical data that can be expanded and collapsed, such as directories and files in a file system.

B is made by Gradient buttons set images to gradient buttons to get B UI

or

Use NSToolBar to use formal ui design.