Xcode 4 and nested projects -- header files not found

I'm having a myriad of problems with Xcode 4 and nested projects that worked just well under Xcode 3.2. Here's a very basic one I cannot solve:

I'm building a cocoa framework that requires another cocoa framework for which I have the source. So I perform the usual steps:

• Drag the .xcodeproj file of the required framework into my main framework project
• In my main framework under TARGETS > MyFramework > Build Phases > Target Dependencies: Add the nested project's target
• Make sure the header files of the nested framework are public
• In Xcode Settings > Locations > Build Location I have it set to Place build products in derived data location (recommended)
• Build products path of both targets are set to ${BUILT_PRODUCTS_DIR} and tell me they are at the DerivedData/Debug (or Release) location
• Architecture settings for both targets are identical

Then I hit [CMD] + B to build and it tells me that it doesn't find the header files of the nested framework. When I check the settings, User Header Search Paths contain the path to DerivedData/Debug, and inside there is the nested framework target with the header files in Versions/A/Headers.

I'm sitting here, anybody an idea what I'm doing wrong?

---

The issue goes away when building for Debug when I change the User header search paths to ${BUILT_PRODUCTS_DIR}/MyFramework.framework/Headers. However this doesn't work when building for Distribution as the frameworks then use their Release settings, which ends up in a different subdirectory...

---

My temporary solution is to also define a Distribution configuration for the nested projects. This way the headers are found and the linker can link successfully.

Here's my synthesized knowledge so far:

Forget the whole public header thing with Xcode, it's a PITA and doesn't work correctly when archiving your app. Instead, have all static library header files on the project level and tell your app where to find it.

1. Ease your pain by making sure all targets have the same name for the build configuration (i.e. add an "AdHoc" and "Deployment" configuration to the static libraries).

2. In build settings, point the Header Search Paths (if you use #include <file.h>) or User Header Search Paths (if you use #include "file.h") to the directory of the static library project. If the static library project is inside your app directory, use this:

   "$(PROJECT_DIR)" (recursive enabled)

   If you have a directory which contains a) the static library project and b) your app, then this should work:

   "$(PROJECT_DIR)/.." (recursive enabled)

3. If the submodule contains compiled libraries, set your Library Search Paths to:

   "$(TARGET_BUILD_DIR)"

4. Make sure all the static library projects that you use have Skip Install set to YES.

5. Again, no public header files (Build Phases » Copy Headers) in any of the static libraries, otherwise Xcode will not be able to archive an app.

6. Make sure to tell Xcode when to build the static libraries, as shown in this Tech Doc from Apple.

---

Old Answer:

I still haven't found a real solution to this problem with static libraries. What works for me is:

• Create an "AdHoc" Configuration for the static library
• Add $(BUILT_PRODUCTS_DIR) to User Header Search paths for the application (with recursive checked) -> this is used when running the app
• In the Xcode menu, select Product > Build For > Build For Archiving

This works, the app finds the header files and builds itself, it ends up in DerivedData//Build/Products/AdHoc-iphoneos/ as an App bundle. Following these simple instructions (dead link) from TestFlightApp.com I can pack this App into an IPA and send it around. Simply selecting to Archive the app from Xcode does again not find the headers, even if they truly are in the AdHoc-iphoneos build directory.

(As of Xcode 5.1)

When the subproject is built by XCode, the subproject header files are copied into the build directory. When archiving, it seems that this copy destination directory is not added to the header/include search path. You'll want to go to your Build Settings and add

$(BUILD_ROOT)/../IntermediateBuildFilesPath/UninstalledProducts/include

to the "Header Search Paths" for the scheme that you use for archiving.

If you're not sure which scheme is used for archiving, go to Product -> Scheme -> Edit Schemes and look for Archive in the left column.

Make sure your third party framework is added as «group» to your main project, so you can see it in your project's hierarchy...

I had the same problem here and I could solve the problem by setting "Build Location" to Place build products in locations specified by targets"

I had this problem: I could build both Debug and App Store configurations, but not Ad Hoc. Building Ad Hoc gave me errors because it couldn't find .h files needed by nested projects.

Turned out I had an expired provisioning lingering in my Release configuration. I updated that provisioning link and now I can both build Ad Hoc and use the Archive feature to package it.

Took me hours to figure it out! My mind just didn't jump from missing .h files to provisioning errors just by itself. =) There might have been an error or warning complaining about the missing provisioning, but if so it was well buried among the hundreds of .h related errors.

I was having the same issue with a Configuration named "Ad Hoc" (as per TestFlight recommendation at http://help.testflightapp.com/customer/portal/articles/402782-how-to-create-an-ipa-xcode-4) and the main project could not find some of the headers from the nested projects. I renamed the project to "AdHoc" (no spaces) and the problem went away; seems like spaces can mess up header search paths in some cases, although I haven't figured out the specifics of when that might happen and why.

I was having this issue with a nested project that built a static library. I found this doc on apples site that completely saved my life.

http://developer.apple.com/library/ios/#DOCUMENTATION/Xcode/Conceptual/ios_development_workflow/AA-Developing_a_Static_Library_and_Incorporating_It_in_Your_Application/archiving_an_application_that_uses_a_static_library.html

I'm so glad I didn't have to muck around with the derived data paths.

For me, this happened after a GIT merge, which created many conflicts, one of them related to the project file. After the merge, I'm sure the structure of the project file changed.

What I ended up doing was going into the project "Build Settings", then looking for "Always Search User Paths" and turning it to Yes.

I guess the merge turned this boolean to No, therefore the project wasn't looking in the right places for the header files.