android - Build NativeActivity using ndk-build -

i trying launch native activity after launching java(i need load library that's why launching nativeactivity java).

how build sample using android.mk? original sample uses gradle. tried build , @ launch library fails load.

fatal exception: main process: sample.simple.com.myapplication, pid: 14917  java.lang.runtimeexception: unable start activity componentinfo{sample.simple.com.myapplication/android.app.nativeactivity}: java.lang.illegalargumentexception: unable load native library: /data/app/sample.simple.com.myapplication/lib/arm64/libnactivity.so 

here snippets of code.

android.mk made following http://brian.io/android-ndk-r10c-docs/programmers_guide/html/md_2__samples_sample--nativeactivity.html

local_path := $(call my-dir) include $(clear_vars) local_module := nactivity local_src_files := main.c local_ldlibs    := -llog -landroid -legl -lglesv1_cm local_static_libraries := android_native_app_glue include $(build_shared_library) $(call import-module,android/native_app_glue) 

java activity

public class dummyactivity extends activity {  @override protected void oncreate(bundle savedinstancestate) {  super.oncreate(savedinstancestate);      system.loadlibrary("nactivity");    intent intent = new intent(dummyactivity.this, android.app.nativeactivity.class);    dummyactivity.this.startactivity(intent);    //  setcontentview(r.layout.activity_dummy); } } 

android manifest

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="display.rendering.simple.com.myapplication">      <application android:label="@string/app_name" android:hascode="true">         <activity android:name="dummyactivity"             android:label="@string/app_name">             <intent-filter>                 <action android:name="android.intent.action.main" />                 <category android:name="android.intent.category.launcher" />             </intent-filter>         </activity>         <activity android:name="android.app.nativeactivity">             <meta-data android:name="android.app.lib_name"                 android:value="nactivity" />         </activity>     </application>  </manifest> 

build.gradle

ndk{     modulename ="nactivity" } sourcesets.main {     jni.srcdirs = []     jni.srcdir "src/main/libs" } 

thanks

your build.gradle disables built-in call ndk-build here:

jni.srcdirs = [] 

this means no native library being built. no library -> no library matching name on device -> loadlibrary error.

you don't need use android.mk file launch native-activity java. other ndk samples document how build , use native code build.gradle. build.gradle file hello-jni great place start.

i advise against using android.mk unless have to, there ndk samples using android.mk if need them.