CMake: How can I copy a directory into the ios application bundle

Question

I have an ios project that builds with CMake 3.1.1, but I am stuck on the last problem - getting CMake to copy the asset directory into the right location for the app.

I have this, which works when running the app in the simulator. However, it does not work, and in fact causes a build failure when archiving because the destination directory it constructs does not exist.

get_target_property(APPLICATION_BIN ${APPLICATION_NAME} LOCATION) get_dotapp_dir(${APPLICATION_BIN} APPLICATION_APP_LOCATION) add_custom_command(TARGET ${PROJECT_NAME} POST_BUILD COMMAND cp -r "${CMAKE_SOURCE_DIR}/assets" "${APPLICATION_APP_LOCATION}")

The directory I am copying has many subdirectories and I need them all preserved. Essentially I want to accomplish with cmake the same thing that happens when I drag the "assets" folder into the ios project underneath "Resources".

Answer 1

Use ${CMAKE_COMMAND} -E copy_directory instead of calling cp.

add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${LOCATION_FOR_THE_APP} DEPENDS "${PROJECT_SOURCE_DIR}/assets" COMMAND -E copy_directory ${PROJECT_SOURCE_DIR}/assets ${CMAKE_CURRENT_BINARY_DIR}/${LOCATION_FOR_THE_APP}) add_custom_target(${CMAKE_CURRENT_BINARY_DIR}/${LOCATION_FOR_THE_APP} DEPENDS

Answer 2

My solution to this is similar to this answer. The goal of my project was to get googletests running on a cross-platform library, in which I had to wrap googletests into an XCTest Bundle. The build tool we are converting to is CMake for obvious reasons.

I ended up doing this as a pre-build step:

add_custom_command(TARGET ExampleTestTarget PRE_BUILD
    COMMAND ${CMAKE_COMMAND} -E copy_directory 
              ${CMAKE_CURRENT_LIST_DIR}/resources $<TARGET_FILE_DIR:ExampleTestTarget>
)

Essentially, at prebuild, CMake will copy everything in the resources folder into the root of the target's bundle. For some reason (probably a CMake thing), XCode picked these resource files up with no issue, so I didn't have to set the files to be RESOURCE files explicitly.

If you're using MacOS Bundles/Packages/etc., you'll have to copy-paste these files into $<TARGET_FILE_DIR:ExampleTestTarget>/Resources instead since this is the default resource location for MacOS xcodeproj's generated by CMake. (There are so many loopholes to get XCTests working in CMake that I advise everyone doing cross-platform gtests to create an executable instead for MacOS so you won't get into any trouble like this anyway).

Note, you won't see the files in XCode unless you add the files in target_sources(), but who cares... it works anyway! Who develops C++ exclusively in iOS? ....