link

/*
I'm using the com.android.tools.build:gradle-experimental:0.7.0 plugin and trying to get a library to build.

$ ./gradlew assemble
Incremental java compilation is an incubating feature.
:app:copyArmeabi-v7aDebugSharedLibraryStlSo
:libraries:testA:copyArmeabi-v7aDebugSharedLibraryStlSo
:libraries:testA:compiletestAArmeabi-v7aDebugSharedLibrarytestAMainC
:libraries:testA:linktestAArmeabi-v7aDebugSharedLibrary
/home/pepp/tools/android/sdk/ndk-bundle/sources/android/native_app_glue/android_native_app_glue.c:233: error: undefined reference to 'android_main'
collect2: error: ld returned 1 exit status

:libraries:testA:linktestAArmeabi-v7aDebugSharedLibrary FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':libraries:testA:linktestAArmeabi-v7aDebugSharedLibrary'.
> A build operation failed.
      Linker failed while linking libtestA.so.
  See the complete log at: file:///home/pepp/workspace/ri/rn/libraries/testA/build/tmp/linktestAArmeabi-v7aDebugSharedLibrary/output.txt

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 4.301 secs

*/

// this is build.gradle for the testA library
apply plugin: 'com.android.model.library'

def ndkDir = System.getenv("ANDROID_NDK_HOME")
def propertiesFile = project.rootProject.file('local.properties')

if (propertiesFile.exists()) {
    Properties properties = new Properties()
    properties.load(propertiesFile.newDataInputStream())
    ndkDir = properties.getProperty('ndk.dir')
}

model {
    android {
        compileSdkVersion 24
        buildToolsVersion "24.0.0"

        defaultConfig {
            minSdkVersion.apiLevel 21
            targetSdkVersion.apiLevel 24
            versionCode 1
            versionName "1.0"

            buildConfigFields {
                create() {
                    type "int"
                    name "VALUE"
                    value "1"
                }
            }
        }

        ndk {
            platformVersion = 21
            moduleName = 'testA'
            stl = 'gnustl_shared'
            cppFlags.add('--std=c++11')
            ldLibs.addAll(['log', 'android', 'stdc++', 'dl'])
            CFlags.addAll(['-Wall'])
        }

        buildTypes {
            release {
                minifyEnabled false
                proguardFiles.add(file("proguard-rules.pro"))
            }
        }

        productFlavors {
            create("arm") {
                ndk {
                    abiFilters.add("armeabi-v7a")
                }
            }
        }

        sources {
            main {
                jni {
                    source {
                        srcDir "cpp"
                        srcDir "${ndkDir}/sources/android/native_app_glue"
                    }
                    exportedHeaders {
                        srcDir "includes"
                        srcDir "${ndkDir}/sources/android/native_app_glue"
                    }
                }
            }
        }
    }
}