问题
Fairly new to the Xcode Developer API and need a little help. When a project is first opened in Xcode, the Object Library displays the full list of UIKit objects available (and other linked frameworks I believe). However, when I switch files in the project navigator to/from any file (.m, .h, .xib, etc), the Object Library list changes; most of the objects are missing - such as NSButton, NSTableView etc. The standard objects are still visible - Label, Round Rect Button, Text Field, etc.
Closing and re-opening the same project appears to restore the Object Library list, but the same issue happens once a different file is opened.
Using Xcode Version 4.2.1, Build 4D502.
Help!
回答1:
I think I see what you are describing. When I first open an iOS project the Object Library is showing objects that are valid for OS X but not iOS (like File Menu Item). When I switch to a xib file the Object Library gets updated to show only the objects that are valid for iOS. Ideally I suppose that wouldn't happen but since you can't do anything with the Object Library while a source file is in the editor no harm is done.
回答2:
If you are developing application for iOS(iPad or iPhone) you will not get that library which contains pop button , check box ,NSButton, NSTableView etc,that library is available for OS X app development. OS and OS X don't use the same graphics library. iOS and OS X development are similar, but not the same. For example - you don't have Cocoa Bindings on iOS.
I you want to check then make one project for iOS & then see your library contents,then create another project for OSX & see your library contents... :D
来源：https://stackoverflow.com/questions/8371482/xcode-developer-api-object-library-objects-disappearing