Building native openCV with NDK on android studio

Question

I am making a C++ project which uses openCV and I wish to build it on android studio using android NDK support.
On doing so I found out that only the experimental version of gradle supports NDK. I am currently using version 0.2.1 of gradle. I imported opencv as a module and copied the libraries to jniLibs folder under src/main/

I tried to compile it but I got certain errors like undefined reference to some functions in parallel.cpp of libopencv_core.a . They were resolved on importing the third party library : libtbb.a

But on running it I got the following errors:
java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "__gnu_thumb1_case_si" referenced by "libtracking_bits.so"

here is my build.gradle :

apply plugin: 'com.android.model.application'

model {
android {
    compileSdkVersion = 21
    buildToolsVersion = "22.0.1"

    defaultConfig.with {
        applicationId = "com.example.vlc.receiver"
        minSdkVersion.apiLevel = 16
        targetSdkVersion.apiLevel = 21
        versionCode = 1
        versionName = "1.0"


    }
}
android.buildTypes {
    release {
        minifyEnabled = false
        proguardFiles += file('proguard-rules.pro')
    }
    debug {
        minifyEnabled = false
    }
}
android.ndk {
    moduleName = "tracking_bits"

    cppFlags += "-fexceptions"
    cppFlags += "-frtti"
cppFlags  += "-I${file("OpenCV-android-sdk/sdk/native/jni/include")}".toString()
cppFlags  += "-I${file("OpenCV-android-sdk/sdk/native/jni/include/opencv")}".toString()

ldLibs += ["android", "EGL", "GLESv2", "dl", "log", "z"]// , "ibopencv_core"
stl = "gnustl_shared"

}


android.productFlavors {
create("arm") {
    ndk.with {
        abiFilters += "armeabi"

        File curDir = file('./')
        curDir = file(curDir.absolutePath)
        String libsDir = curDir.absolutePath+"\\src\\main\\jniLibs\\armeabi\\" //"-L" +

        ldLibs += libsDir + "libopencv_calib3d.a"
        ldLibs += libsDir + "libopencv_core.a"
        ldLibs += libsDir + "libopencv_features2d.a"
        ldLibs += libsDir + "libopencv_flann.a"
        ldLibs += libsDir + "libopencv_hal.a"
        ldLibs += libsDir + "libopencv_highgui.a"
        ldLibs += libsDir + "libopencv_imgcodecs.a"
        ldLibs += libsDir + "libopencv_imgproc.a"
        ldLibs += libsDir + "libopencv_java3.so"
        ldLibs += libsDir + "libopencv_ml.a"
        ldLibs += libsDir + "libopencv_objdetect.a"
        ldLibs += libsDir + "libopencv_photo.a"
        ldLibs += libsDir + "libopencv_shape.a"
        ldLibs += libsDir + "libopencv_stitching.a"
        ldLibs += libsDir + "libopencv_superres.a"
        ldLibs += libsDir + "libopencv_ts.a"
        ldLibs += libsDir + "libopencv_video.a"
        ldLibs += libsDir + "libopencv_videoio.a"
        ldLibs += libsDir + "libopencv_videostab.a"
        ldLibs += "OpenCV-android-sdk\\sdk\\native\\3rdparty\\libs\\armeabi\\libtbb.a"
    }
}
}

}

dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:22.2.1'
compile project(':openCVLibrary300')
}

I am stuck. Please help.

Answer 1

I added all the 3rd party libraries too and this allowed to compile for arm. To be fair, I also added the 3rd party libraries in jniLibs, just to avoid changing the path as you did up there. Otherwise, I have exactly the same configuration as you, to the point that I copied and pasted your file in a previous stage.

        ldLibs += libsDir + "libIlmImf.a"
        ldLibs += libsDir +  "liblibjpeg.a"
        ldLibs += libsDir + "liblibjasper.a"
        ldLibs += libsDir +"liblibpng.a"
        ldLibs += libsDir +"liblibwebp.a"