title: Android Java NDK/JNI - UnsatisfiedLinkError: Native method not found [...] Ljava/lang/String;
body: <p>My program is intended to be a simple program that uses the Android NDK to implement some c++ code in an android app. The guide i have followed is <a href="http://taylorpeer.com/hello-world-cpp-android-ndk/" rel="nofollow">http://taylorpeer.com/hello-world-cpp-android-ndk/</a> but when i run the program i get the error</p>
  
  <p><code>java.lang.UnsatisfiedLinkError: Native method not found: com.example.spotifywidget.MainActivity.stringFromJNI:()Ljava/lang/String;</code></p>
  
  <p>and i get it when i run the line to call my c++ method via stringFromJNI(). Bellow i have included the MainActivity.java</p>
  
  <pre><code>package com.example.spotifywidget;
  
  import android.os.Bundle;
  import android.app.Activity;
  import android.view.Menu;
  
  public class MainActivity extends Activity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          System.err.println("HELLO!");
  
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
      }
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
  
          // Inflate the menu; this adds items to the action bar if it is present.
          getMenuInflater().inflate(R.menu.activity_main, menu);
  
          return true;
      }
      public native String stringFromJNI();     //A string to store the return in
      @Override
      public void onBackPressed() {
  
          System.err.println(this.stringFromJNI());   //Call the c++ method
  
      }
      static{
          System.loadLibrary("SpotifyWidget");    //Load the c++ library
      }
  }
  </code></pre>
  
  <p>The spotifywidget.cpp</p>
  
  <pre><code>#include &lt;jni.h&gt;
  #include &lt;string.h&gt;
  //#include &lt;api.h&gt;
  
  extern "C"{
  
  JNIEXPORT jstring JNICALL
  Java_com_example_SpotifyWidget_stringFromJNI
  (JNIEnv *env, jobject obj){
      return env-&gt;NewStringUTF("Hello from JNI!");
  }
  
  }
  </code></pre>
  
  <p>the android.mk</p>
  
  <pre><code>LOCAL_PATH := $(call my-dir)
  
  include $(CLEAR_VARS)
  
  LOCAL_MODULE    := SpotifyWidget
  LOCAL_SRC_FILES := SpotifyWidget.cpp
  include $(BUILD_SHARED_LIBRARY)
  </code></pre>
  
  <p>and the logcat output</p>
  
  <pre><code>09-28 18:25:40.176: E/Trace(991): error opening trace file: No such file or directory (2)
  09-28 18:25:40.487: D/dalvikvm(991): Trying to load lib /data/data/com.example.spotifywidget/lib/libSpotifyWidget.so 0x41196fc0
  09-28 18:25:40.487: D/dalvikvm(991): Added shared lib /data/data/com.example.spotifywidget/lib/libSpotifyWidget.so 0x41196fc0
  09-28 18:25:40.496: D/dalvikvm(991): No JNI_OnLoad found in /data/data/com.example.spotifywidget/lib/libSpotifyWidget.so 0x41196fc0, skipping init
  09-28 18:25:40.506: W/System.err(991): HELLO!
  09-28 18:25:40.766: D/libEGL(991): loaded /system/lib/egl/libEGL_emulation.so
  09-28 18:25:40.776: D/(991): HostConnection::get() New Host Connection established 0x2a0e3558, tid 991
  09-28 18:25:40.867: D/libEGL(991): loaded /system/lib/egl/libGLESv1_CM_emulation.so
  09-28 18:25:40.885: D/libEGL(991): loaded /system/lib/egl/libGLESv2_emulation.so
  09-28 18:25:40.986: W/EGL_emulation(991): eglSurfaceAttrib not implemented
  09-28 18:25:40.996: D/OpenGLRenderer(991): Enabling debug mode 0
  09-28 18:25:44.459: W/dalvikvm(991): No implementation found for native Lcom/example/spotifywidget/MainActivity;.stringFromJNI:()Ljava/lang/String;
  09-28 18:25:44.459: D/AndroidRuntime(991): Shutting down VM
  09-28 18:25:44.459: W/dalvikvm(991): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
  09-28 18:25:44.466: E/AndroidRuntime(991): FATAL EXCEPTION: main
  09-28 18:25:44.466: E/AndroidRuntime(991): java.lang.UnsatisfiedLinkError: Native method not found: com.example.spotifywidget.MainActivity.stringFromJNI:()Ljava/lang/String;
  09-28 18:25:44.466: E/AndroidRuntime(991):  at com.example.spotifywidget.MainActivity.stringFromJNI(Native Method)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at com.example.spotifywidget.MainActivity.onBackPressed(MainActivity.java:29)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.app.Activity.onKeyUp(Activity.java:2131)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.view.KeyEvent.dispatch(KeyEvent.java:2633)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.app.Activity.dispatchKeyEvent(Activity.java:2361)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1819)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.view.ViewRootImpl.deliverKeyEventPostIme(ViewRootImpl.java:3577)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.view.ViewRootImpl.handleImeFinishedEvent(ViewRootImpl.java:3547)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:2797)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.os.Handler.dispatchMessage(Handler.java:99)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.os.Looper.loop(Looper.java:137)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at android.app.ActivityThread.main(ActivityThread.java:4745)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at java.lang.reflect.Method.invokeNative(Native Method)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at java.lang.reflect.Method.invoke(Method.java:511)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  09-28 18:25:44.466: E/AndroidRuntime(991):  at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>Thanks in advance for any help :)</p>