Android Studio:OpenCv:Face-detection = java.lang.UnsatisfiedLinkError: Couldn't load detection_based_tracker from loader dalvik.system.PathClassLoader -

java.lang.unsatisfiedlinkerror: couldn't load detection_based_tracker  loader dalvik.system.pathclassloader[dexpathlist[[zip file  "/data/app/org.opencv.samples.facedetect-9.apk"],nativelibrarydirectories= [/data/app-lib/org.opencv.samples.facedetect-9, /vendor/lib, /system/lib]]]:  findlibrary returned null 

and have error.

at.org.opencv.samples.facedetect.fdactivity$1.onmanagerconnected(fdactivity.java:67)

related rows:

66:                // load native library after(!) opencv initialization 67:                system.loadlibrary("detection_based_tracker"); 

gradle version: 2.14.1

plugin version: 2.2.0 build.gradle(app):

apply plugin: 'com.android.application' android { compilesdkversion 25 buildtoolsversion "25.0.2"  defaultconfig {     applicationid "org.opencv.samples.facedetect"     minsdkversion 8     targetsdkversion 8      ndk {         modulename "detection_based_tracker"     } } sourcesets.main {     jnilibs.srcdir 'src/main/libs'     jni.srcdirs = [] }  buildtypes {     release {         minifyenabled false         proguardfiles getdefaultproguardfile('proguard-android.txt'), 'proguard-rules.txt'     } } dependencies { compile project(':opencvlibrary300') } 

i added lines dont have libs directory under main directory:

sourcesets.main { jnilibs.srcdir 'src/main/libs' jni.srcdirs = [] } 

screenshot of left bar

also there no *.so file.

android.mk

local_path := $(call my-dir) include $(clear_vars) #opencv_install_modules:=off #opencv_lib_type:=shared ifdef opencv_android_sdk ifneq ("","$(wildcard $(opencv_android_sdk)/opencv.mk)") include ${opencv_android_sdk}/opencv.mk else include ${opencv_android_sdk}/sdk/native/jni/opencv.mk endif else include ../../sdk/native/jni/opencv.mk endif local_src_files  := detectionbasedtracker_jni.cpp local_c_includes += $(local_path) local_ldlibs     += -llog -ldl local_module     := detection_based_tracker include $(build_shared_library) 

aplication.mk

app_stl := gnustl_static app_cppflags := -frtti -fexceptions app_abi := armeabi-v7a app_platform := android-8 

how can run face-detection project opencv? should add in build.gradle?