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Android JNI APK Packing

Posted by: admin June 15, 2020 Leave a comment

Questions:

I have implemented a JNI android application. This application requires a few additional ‘Shared Libs’ to be packed as part of the APK. Using Ecplise, I have added these libs to the project’s ‘/libs/armeabi’ folder.

However, when launching the application (through the integrated debugger), my added ‘Shared Libs’ are removed from the ‘armeabi’ folder.

  • How can I prevent these additional libs from being removed?
  • How can I make sure the additional required SOs are packed in the APK?
How to&Answers:

You don’t need to copy this libraries to libs folder yourself. This job should be done by the ndk-build.

These two steps should be enough:

  1. Create mylibs (you can use any other name instead) folder on the root level of your project. And put your libraries into this folder.

  2. For each library add the following lines before the include $(CLEAR_VARS) statement replacing mylib with you library name:

    include $(CLEAR_VARS)
    LOCAL_MODULE:=mylib
    LOCAL_SRC_FILES:=../mylibs/libmylib.so
    include $(PREBUILT_SHARED_LIBRARY)
    

(You might need slightly different path for LOCAL_SRC_FILES. It depends on your Eclipse configuration.)

Answer:

One more note to add in this context is that the path to the external SharedLib MUST BE relative to the jni directory ( or to whatever spcified @ LOCAL_PATH ), that is, “LOCAL_SRC_FILES := ../../../Android/ffmpeg/libavcodec/libavcodec.so” will work where the absolute path will not.