Problem reading sensor plugin, event won't trigger

When I run my plugin onSensorChanged won't trigger, leaving me without any information from the sensors.

Here is my Java Class code:

 package com.skanska.helloandroid;
 
 import android.app.Activity;
 import android.content.Context;
 import android.hardware.Sensor;
 import android.hardware.SensorEvent;
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
 
 
 public class HelloAndroidActivity extends Activity implements SensorEventListener{
 
 private SensorManager mSensorManager;
 private float[] mGData = new float[3];
 private float[] mMData = new float[3];
 private float[] mR = new float[16];
 private float[] mI = new float[16];
 private float[] mOrientation = new float[3];
 private Sensor msensor, gsensor;
     
 public float deg = 0;
 private String degString;
     
 public HelloAndroidActivity(Activity currentActivity) {
 mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
         
 gsensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
 msensor = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
         
 mSensorManager.registerListener(this, gsensor, SensorManager.SENSOR_DELAY_GAME);
 mSensorManager.registerListener(this, msensor, SensorManager.SENSOR_DELAY_GAME);
 }
   
 public void onAccuracyChanged(Sensor sensor, int accuracy) {
 }
 
 public void onSensorChanged(SensorEvent event) {        
         
 int type = event.sensor.getType();
 if (type == Sensor.TYPE_ACCELEROMETER) {
             
 for (int i=0 ; i<3 ; i++)
 mGData[i] = event.values[i];
             
 }
 else if (type == Sensor.TYPE_MAGNETIC_FIELD) {
             
 for (int i=0 ; i<3 ; i++)
 mMData[i] = event.values[i];
             
 } 
 else {
 return;
 }
         
 SensorManager.getRotationMatrix(mR, mI, mGData, mMData);
 
 SensorManager.getOrientation(mR, mOrientation);
         
 final float radtodeg = (float)(180.0f/Math.PI);
 deg = mOrientation[0]*radtodeg;
 }
 
 public String getDeg(){
 degString = Float.toString(deg);
 return degString;
 }    
 }

My javabridge(.cpp):

 include <stdlib.h>
 include <jni.h>
 include <android/log.h>
 
 extern "C"
 {
 
 JavaVM*    java_vm;
 jobject    HelloAndroidActivity;
 jmethodID getDeg;
 
 jint JNI_OnLoad(JavaVM* vm, void* reserved)
 {
 java_vm = vm;
 
 JNIEnv* jni_env = 0;
 java_vm->AttachCurrentThread(&jni_env, 0);
     
 jclass cls_Activity = jni_env->FindClass("com/unity3d/player/UnityPlayer");
 jfieldID fid_Activity = jni_env->GetStaticFieldID(cls_Activity, "currentActivity", "Landroid/app/Activity;");
 jobject obj_Activity = jni_env->GetStaticObjectField(cls_Activity, fid_Activity);
     
 jclass cls_HelloAndroidActivity    = jni_env->FindClass("com/skanska/helloandroid/HelloAndroidActivity");
 jmethodID mid_HelloAndroidActivity = jni_env->GetMethodID(cls_HelloAndroidActivity, "<init>", "(Landroid/app/Activity;)V");
 jobject obj_HelloAndroidActivity = jni_env->NewObject(cls_HelloAndroidActivity, mid_HelloAndroidActivity, obj_Activity);
     
 HelloAndroidActivity = jni_env->NewGlobalRef(obj_HelloAndroidActivity);
 getDeg = jni_env->GetMethodID(cls_HelloAndroidActivity, "getDeg", "()Ljava/lang/String;");
 
 return JNI_VERSION_1_6;
 }
 
 char* dec = 0;
 const char* getDeclination()
 {
 
 
 JNIEnv* jni_env = 0;
 java_vm->AttachCurrentThread(&jni_env, 0);
 
 jstring str_dec    = (jstring)jni_env->CallObjectMethod(HelloAndroidActivity, getDeg);
     
 jsize stringLen = jni_env->GetStringUTFLength(str_dec);
     
 dec = new char[stringLen+1];
 
 const char* content = jni_env->GetStringUTFChars(str_dec, 0);
     
 strcpy(dec, content);
 
 return dec;
 }
 }

My C# Call javacode script:

 using UnityEngine;
 using System;
 using System.Collections;
 using System.Runtime.InteropServices;
 
 public class CallJavaCode : MonoBehaviour {
 
     
 [DllImport("javabridge")]
 private static extern IntPtr getDeclination();
 
 
 
 public float   deg;
 private string decString;
 
 
 
 IntPtr stringPtr = getDeclination();
     
 void Start ()
 {
 stringPtr=getDeclination();
 Debug.Log("stringPtr = " +stringPtr);
 String cache = Marshal.PtrToStringAnsi(stringPtr);
 Debug.Log("getDeclination returned " + cache);
 decString = cache;
 
 deg = float.Parse(decString);    
         
 Debug.Log("Deg= " + deg);
 transform.eulerAngles = new Vector3(0, 0, deg);
     }
 void Update()
     {
 stringPtr = getDeclination();
 Debug.Log("stringPtr = " +stringPtr);
 String cache = Marshal.PtrToStringAnsi(stringPtr);
 Debug.Log("getDeclination returned " + cache);
 decString = cache;
         
 deg = float.Parse(decString);
 
 transform.eulerAngles = new Vector3(0, 0, deg);
 Debug.Log("Deg = " + deg);        
     }    
 
 void OnGUI ()
 {
 GUI.Label(new Rect (15, 125, 450, 100), decString);        
 }
 }

I might aswell post my manifest since I have no clue what so ever manifest:

 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 package="com.skanska.helloandroid"
 android:versionCode="1"
 android:versionName="1.0">
 <uses-sdk android:minSdkVersion="11" />
 
 <application android:icon="@drawable/icon" android:label="@string/app_name" android:debuggable="true">
 <activity android:name=".HelloAndroidActivity"
 android:label="@string/app_name">
 <intent-filter>
 <action android:name="android.intent.action.MAIN" />
 <category android:name="android.intent.category.LAUNCHER" />
 </intent-filter>
 </activity>
 
 </application>
 </manifest>

Am I missing something obvious? Is it even possible to make a event based plugin?

Thanks in advance,

Martin