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androidandroid-studiojava-native-interfaceapk

Missing step to create a new AS project and get a lib folder populated on my device upon installation

Goal

I want the libs present in my APK to be available on my device from a fixed location when I install my APK.

I opened another question about this issue based on my existing project. This time, I started a brand new project from scratch in order to reduce the unknowns and make my question simpler to resolve.

Steps I followed

With Android Studio 4.0.1, I do the following:

  • Start a new Android Studio project

  • Select Native C++

  • Set project name to test

  • Select Java as language

  • Use default toolchain

  • Build -> Make Project

Under the project view, I verify that my app-debug.apk has a lib folder containing a few subdirectories, each with at least the libnative-lib.so that was built for this project accordingly to the default CMakeLists.txt rules.

I would like this .so to be accessible from my device when I install my APK (I have a more complex project in which I create .so that I want accessible from outside the APK).

However, from my project folder, when I run:

c:\Users\xxx\AndroidStudioProjects\test>adb install app\build\outputs\apk\debug\app-debug.apk
Performing Streamed Install
Success

c:\Users\xxx\AndroidStudioProjects\test>adb shell ls /data/data/com.example.test
cache
code_cache

Other changes I tried

None of the following further changes allowed me to see additional files under /data/data/com.example.test

  • Added android.bundle.enableUncompressedNativeLibs=false to gradle.properties

  • Added

    android {
    ...
    sourceSets.main {
        jniLibs.srcDirs = ['libs']
        jni.srcDirs = []
    }

    to build.gradle do not change anything to this.

  • Added set(distribution_DIR ${CMAKE_SOURCE_DIR}/libs) to CMakeLists.txt

Solution

  • Native libraries are not placed in /data/data/your.app but in /data/app/your.aapp-<key-hash>==/lib/<ABI>, for example on my target:

    hikey960:/ # cd /data/app/com.example.dlopen-6BSPeAN9VvjFlCxIzLHX9A\=\=/lib/arm64                                                                                     
hikey960:/data/app/com.example.dlopen-6BSPeAN9VvjFlCxIzLHX9A==/lib/arm64 # ls -als
total 1352
   4 drwxr-xr-x 2 system system    4096 2020-11-06 12:43 .
   4 drwxr-xr-x 3 system system    4096 2020-11-06 12:43 ..
1044 -rwxr-xr-x 1 system system 1067256 1981-01-01 01:01 libnative-lib.so
 300 -rwxr-xr-x 1 system system  305360 1981-01-01 01:01 libplugin.so

    Also native libraries are archived by default and can not be accessible, for extracting them it is needed to set android:extractNativeLibs="true" in AndroidManifest.xml (for example like here: https://github.com/nkh-lab/ndk-dlopen/blob/master/dlopen/app/src/main/AndroidManifest.xml).