Include files with different prefixes in apk

Issue

I have a project with native libraries that I want to use, files with this format: lib<name>.so do get included into apk. But files with <name>.so format does not.

Is there a way to include the later type into apk in lib directory?

If not, is there a way to include the files into a directory inside apk, where I can load it from my native code?

Solution

The short answer is "no". The native binaries will only be packed into APK, and extracted to executable files upon installation, if their names follow the lib….so pattern.

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Note that these libraries will be extracted to files according to the ABI of the target system. The installer does not check the actual properties of the file. The decision is based on the name of the folder under lib in the APK structure.

If you add the attribute extractNativeLibs=false to the application tag in AndroidManifest.xml of your APK, the installer (on Android Nougat and higher) will not extract the native libraries.

You can trick the system and have files that don't follow the above rule to the lib folder of APK, but there is very little sense in it, because they will never be extracted by the loader (it may also extract file gdbserver if the file is there).

The common practice is to put the arbitrary files in the assets folder of your APK, and extract them programmatically when the app runs for the first time after install. You cannot extract these files to the secured location where the usual native libraries go. You should not extract the native libraries to sdcard (e.g. getExternalFilesDir()), because the system may not allow execution of the files there, regardless of the execute access flag on the file. Make sure that you use the correct ABI flavour.

You can peek at the source code of Nougat native lib loader that can load native libraries from the APK without extraction, and use it to load your custom libraries directly from the assets folder of your APK.

Answered By - Alex Cohn