Android NDK-试图链接不存在的预构建库的构建

Question

I just inherited some legacy code, which is currently able to build on our build server and I am trying to get it run on Android Studio, and it is having issue where the build fails because it is trying to point to a (non-existent) MIPS version of a prebuilt library.

I get the following error:

libraryname: LOCAL_SRC_FILES points to a missing file.
Check that .../libraryname/mips/libraryname.so exists.

This file does not exist, but I don't understand why the build tool is looking for it.

My Application.mk file has this entry:

APP_ABI := armeabi armeabi-v7a x86 x86_64

My Android.mk file has this entry (library name generalized):

include $(CLEAR_VARS)
LIBRARY_NAME_PATH := libraryname/$(TARGET_ARCH_ABI)
LOCAL_MODULE := modulename
LOCAL_SRC_FILES := $(LIBRARY_NAME_PATH)/mobulename.so
include $(PREBUILT_SHARED_LIBRARY)

Confusingly, TARGET_ARCH_ABI doesn't seem to be set anywhere, so I'm not really sure what is happening there.

Other notes, when I build this from the command line with NDK-build, it works just fine, only creating the 4 architectures requested.

As I mentioned, there should be no need for any code changes, since this exact code is successfully building on our build server. I am assuming I just have something configured wrong.

Answer 1

Traditionally, NDK used APP_ABIS setting (usually defined in Application.mk file) to choose the list of architectures to build. NDK supports today ARM, Intel and MIPS processors in 32 and 64-bit modes.

The gradle plugin used by Android Studio ignores APP_ABIS and you must define abiFilters in your build.gradle to specify the architectures to build.

This is especially important when your project uses prebuilt third-party libraries, because quite often, as in your case, these libraries are available only to a subset of all possible architectures.

ndk-build invokes the Android.mk script in a loop, each time setting $(TARGET_ARCH_ABI) to chosen architecture, one of arm64-v8a x86_64 mips64 armeabi-v7a armeabi x86 mips