Xcode 4.2 how include one project into another one?

Make sure the project you want to add as subproject it's not open, before you add it or drop it.

You can just drag-and-drop any xcode-project file (*.xcodeproj) into the project navigation pane of your desired parent-project.

You then may need to add target dependencies, depending on your needs.

Is that what you mean?

This makes a lot of sense when you are trying to add a static library to your xcode projects. There are a couple steps required for doing this. First, make sure that the static library project is not open in XCode.

Then start by dragging and dropping the static library xcodeproj file (from the Finder) onto your app's xcode project.

After this you need to add this library to your app's build phases. Click on the main project, and select the BuildPhases tab of the target.

You're going to want to add the other project to the Target Dependencies and to your Link Binary With Libraries Section.

Finally, the app needs to be aware of your headers. Therefore, you need to add the path to your static libraries classes to your User Header Search Paths. Go to the Build Settings of the Main Target and search for Header Search Path.

This will make your app aware of the new static library.

Sometimes you need to add a few Other Linker Flags. In the Build Settings search for Other Linker Flags and add -all_load and -ObjC

Hope this helps, I know the first time I tried to do this I was banging my head against the wall for a while.

Make sure to choose "create groups" instead of "create folder references". If your folder is blue instead of yellow, then you have a folder reference. The folder should be yellow.