Android version(s): N/A (didn't get that far)
Android device(s): N/A (as above)
Oboe version: 1.5.0
App name used for testing: A closed-source app, sorry

Short description
This is a build issue.

I've made an Android library which uses Oboe (from prefab), called MidiPlayer. As advised in GettingStarted.md, I'm using libc++_shared.so.

I also have an Android app. In the app, I include both MidiPlayer and a totally unrelated 3rd party library. I get the following error:

More than one file was found with OS independent path 'lib/arm64-v8a/libc++_shared.so'. If you are using jniLibs and CMake IMPORTED targets, see https://developer.android.com/studio/preview/features#automatic_packaging_of_prebuilt_dependencies_used_by_cmake

Unhelpfully, that link is wrong. But I think it's supposed to point here, however this is irrelevant (I don't have a jniLibs directory).

The issue is that by following the advice in GettingStarted.md, I end up with a copy of libc++_shared.so in the package. Specifically, when I look in my .gradle folder I see a folder called jetified-midiplayer-<version> which contains a jni directory, and for each platform folder it contains libc++_shared.so. This appears to be clashing with other Android libraries which do the same thing. How am I supposed to do this? Should I just use the c++_static Android STL? I figure that's bad form because it increases the size of my app. It also goes against the advice in GettingStarted.md.

Detailed description

Disclaimer: I'm not experienced with C or C++. I am just trying to follow instructions.

My library (MidiPlayer) has a build.gradle that looks something like this:

apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'maven-publish'

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.0"

    defaultConfig {
        minSdkVersion 23
        targetSdkVersion 30
        versionCode project.versionCode
        versionName project.versionName
        ...
        externalNativeBuild {
            cmake {
                arguments "-DANDROID_STL=c++_shared"
            }
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
            version "3.10.2"
        }
    }
    buildFeatures {
        prefab true
    }
}

dependencies {
    ...
    implementation 'com.google.oboe:oboe:1.5.0'
}

My CMakeLists.txt looks like this:

cmake_minimum_required(VERSION 3.4.1)

add_library (nativeMidiSynth SHARED path/to/source1.cpp path/to/source2.cpp)

find_package (oboe REQUIRED CONFIG)

target_link_libraries(nativeMidiSynth log oboe::oboe)

I then publish this Android library to a maven repository. Over in my app (separate codebase), I pull this and the clashing library (pdfium, a dependency of android-pdf-viewer) in with:

dependencies {
    implementation 'com.github.barteksc:android-pdf-viewer:3.2.0-beta.1'
    implementation "com.example:midiplayer:0.1.0"
}

Then, when building I see the error mentioned above. By searching through my .gradle directory I found that these are the two packages that contain libc++_shared.so. For example, my MidiPlayer's jni\arm64-v8a directory (in C:\Users\chris\.gradle\caches\transforms-2\files-2.1\cb0f0382d7f01637cf539290e3e3d990\jetified-midiplayer-1.3.1) contains 3 files:

• libc++_shared.so
• libnativeMidiSynth.so - my native library which uses oboe
• liboboe.so

pdfium's jni\arm64-v8a directory (in C:\Users\chris\.gradle\caches\transforms-2\files-2.1\d99f523756be4de3c5d148ea12d9cbab\jetified-pdfium-android-1.9.0) contains these files:

• libc++_shared.so
• libjniPdfium.so
• libmodft2.so
• libmodpdfium.so
• libmodpng.so

So how do I, you know, share this library? Why does it cause a clash?