title: Trouble with getSystemService(SENSOR_SERVICE) - Already implemented context
body: <p>I'm trying to create a Service for my Gyroscope in Android, but I keep having trouble with getSystemService.</p>
  
  <p>I've been searching through the forums, trying to find a solution, but in most cases it is a matter of simply importing the context from the MainActivity.</p>
  
  <pre><code>public class GyroData implements SensorEventListener {
  
  private final Context mContext;
  protected SensorManager mSensorManager;
  
  public GyroData(Context context) {
      mContext = context;
      mSensorManager = (SensorManager) mContext.getSystemService(Context.SENSOR_SERVICE);
  }
  </code></pre>
  
  <p>As you can see above, I've already done that, yet I'm still getting the following error.</p>
  
  <pre><code>java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{sw806f16.p8project/sw806f16.p8project.CameraActivity}: java.lang.IllegalStateException: System services not available to Activities before onCreate()
  at sw806f16.p8project.GyroData.setupSensorManager(GyroData.java:24)
  </code></pre>
  
  <p>EDIT: Added code from MainActivity</p>
  
  <pre><code>public class CameraActivity extends Activity implements LocationListener, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {
  public static final String TAG = "CameraActivity";
  
  LocationService gps = new LocationService(this);
  GyroData gyro = new GyroData(this);
  </code></pre>