NDK module not included in final APK

Issue

I've inherited a really messy android project with a lot of NDK dependencies and having a lot of problems with getting gradle to correctly link and include all .so and .a files into the resulting apk.

The project consists of some java code that sets up some activities and call into a big NDK library, built from C++ which in turn links with a dosens of 3rd party library (prebuilt or built from source).

I have managed to make it build with the latest gradle experimental plugin, but for some reason, my module isn't included in the apk while my 3rd party .so files are even though I can see that gradle have built my module into a .so file which it have placed in the build directory.

My build.gradle looks like this:

apply plugin: 'com.android.model.application'
model {
    android {
        compileSdkVersion = 23
        buildToolsVersion = "22.0.1"
        defaultConfig.with {
            applicationId = "<removed>"
            minSdkVersion.apiLevel = 7
            targetSdkVersion.apiLevel = 23
            versionCode = 1
            versionName = "1.0"
        }
        ndk {
            moduleName = "XM"
            CFlags.add("-I${file("src/main/jni")}".toString())
            cppFlags.addAll(["-I${file("../../3rd_part/android/osg")}".toString()])
            cppFlags.addAll(["-I${file("../../3rd_part/android/opus")}".toString()])
            ldFlags.add("-L${file("src/main/jniLibs/armeabi-v7a")}".toString())
            ldLibs.addAll(["osgdb_jpeg", "osgdb_freetype", "jpeg","argsub_es", "jnigraphics", "android", "log"])
            stl = "gnustl_shared"
            abiFilters.add("armeabi-v7a")
        }

        sources {
            main {
                jni {
                    source {
                        srcDir "../../core"
                        srcDir "src/main/jni"
                    }
                }

            }
        }
        lintOptions.abortOnError = false
    }

    android.buildTypes {
        release {
            minifyEnabled = false
            proguardFiles.add(file('proguard-rules.txt'))
        }
    }

}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:support-v4:23.0.0'
    compile 'com.android.support:appcompat-v7:23.0.0'
    compile 'com.android.support:design:23.0.0'
    compile 'com.wunderlist:sliding-layer:1.1.1'

}

So to sum up my question: why does gradle build my module (libXM.so), place it into build/libs/xM/shared/armeabi-v7a/debug, but not include it into my final apk file?

Solution

I didn't get several things: if you want to build a shared library with gradle, then you have to use apply plugin: 'com.android.model.library' and not application

If you want to build an application and use prebuilt library, then you have to write something like this:

    sources {
        main {
            jni {
                source {
                    srcDir "../../core"
                    srcDir "src/main/jni"
                }
                dependencies{
                    library "XM" linkage "shared"
                }

And, of course, to set ldFlags previously.

Answered By - user1056837