问题
I look through the internet I didn't find the answer so here is the problem
I had a project that I used cocoa pods in it and so open it through workspace file that cocoa pods created for me, but after update my os (clean install) to MacOS Sierra the .xcodeproj file is disabled when I open the project within .xcworkspace and every file underneath is not showing, I had many files grouped into Xcode folders under .xcodeproj file
来源：https://stackoverflow.com/questions/39673705/xcodeproj-file-within-xcworkspace-created-through-cocoa-pods-is-disabled