It is enough to copy files, if you copy all files and files from the project file do not refer to absolute paths.
Please note that you do not need to choose absolute paths. I'm not sure about the details, but I ended up with absolute paths in the projects without doing this explicitly.
For example, here is a project with a missing file:

When I select the missing file, I see that it uses the absolute path:

At this point you have two options:
- , , . , ; , Xcode
DetailViewController.m SomeUnrelatedFile.m, . , , : ( ), . - , , . , , , , : . .