Couldn't load native_sample: findLibrary returned null opencv4android

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So I was able to run all Android samples except ones using ndk.

I get this in console `

**** Build of configuration Default for project OpenCV Tutorial 3 - Add Native OpenCV ****

D:\pbIxtex\android-ndk-r7c-windows\android-ndk-r7c\ndk-build.cmd 
Install        : libnative_sample.so => libs/armeabi-v7a/libnative_sample.so


**** Build Finished ****

and this is the logcat

10-26 21:28:44.994: E/AndroidRuntime(9469): FATAL EXCEPTION: main
10-26 21:28:44.994: E/AndroidRuntime(9469): java.lang.UnsatisfiedLinkError: Couldn't load native_sample: findLibrary returned null
10-26 21:28:44.994: E/AndroidRuntime(9469):     at java.lang.Runtime.loadLibrary(Runtime.java:429)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at java.lang.System.loadLibrary(System.java:554)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at org.opencv.samples.tutorial3.Sample3Native$1.onManagerConnected(Sample3Native.java:27)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at org.opencv.android.AsyncServiceHelper$1.onServiceConnected(AsyncServiceHelper.java:206)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1064)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1081)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at android.os.Handler.handleCallback(Handler.java:587)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at android.os.Handler.dispatchMessage(Handler.java:92)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at android.os.Looper.loop(Looper.java:130)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at android.app.ActivityThread.main(ActivityThread.java:3835)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at java.lang.reflect.Method.invokeNative(Native Method)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at java.lang.reflect.Method.invoke(Method.java:507)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
10-26 21:28:44.994: E/AndroidRuntime(9469):     at dalvik.system.NativeStart.main(Native Method)

if i try ndk-build.cmd -B it goes like this

**** Build of configuration Default for project OpenCV Tutorial 3 - Add Native OpenCV ****

D:\pbIxtex\android-ndk-r7c-windows\android-ndk-r7c\ndk-build.cmd -B 
"Compile++ thumb : native_sample <= jni_part.cpp

Prebuilt       : libgnustl_static.a <= <NDK>/sources/cxx-stl/gnu-libstdc++/libs/armeabi-v7a/

SharedLibrary  : libnative_sample.so

Install        : libnative_sample.so => libs/armeabi-v7a/libnative_sample.so


**** Build Finished ****

but the error is the same. I've tried CDT 8.1.0 and 8.0.2 and ndk r8b and r7c.

I've downloaded the samples from google play and they worked. Any suggestions?