title: unresolved reference: override (onCreate)
body: <p>why is there an <strong>unresolved reference</strong> on override at the <code>onCreate</code> method? (<strong>Kotlin</strong>)</p>
  
  <pre><code>// unresolved reference: override
  override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      // MapFragment erstellen und anzeigen
      startMapFragment()
      mapFragment.getMapAsync(this)
  
      // OnClickListener für SpeicherDetailActivity
      btnDetailSpeichern.setOnClickListener {
          val detailIntent = Intent(this, SpeicherDetailActivity::class.java)
          startActivity(detailIntent)
      }
  }
  </code></pre>
  
  <p>I tried to clean and rebuild the Project.
  I deleted the onCreate method and let AndroidStudio generate an new one (by pressing CTRL + O).
  I copied an onCreate method from another Activitiy,
  but nothing of this worked.</p>
  
  <p>Here is the full Activity:</p>
  
  <pre><code>class SpeicherActivity : AppCompatActivity(), OnMapReadyCallback {
  
  // Variablem für MapFragment erstellen
  var mapFragment = MapFragment.newInstance()
  var fragmentTransaction = fragmentManager.beginTransaction()
  var muennerstand : Ort = Ort(20.0, 5.0, "Münnerstadt", "", 0.0f)
  var standartMarker = MarkerOptions().position(LatLng(muennerstand.latitute, muennerstand.longitute)).title("standart")
  
  // GPS TEST
  val locManager = LocationManager.GPS_PROVIDER.
  
  
  // unresolved reference: override
  override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      // MapFragment erstellen und anzeigen
      startMapFragment()
      mapFragment.getMapAsync(this)
  
      // OnClickListener für SpeicherDetailActivity
      btnDetailSpeichern.setOnClickListener {
          val detailIntent = Intent(this, SpeicherDetailActivity::class.java)
          startActivity(detailIntent)
      }
  }
  
  
  
  // MapFragment erstellen und anzeigen
  fun startMapFragment() {
      fragmentTransaction.add(R.id.fragmentContainer, mapFragment)
      fragmentTransaction.commit()
  }
  
  override fun onMapReady(mMap : GoogleMap?) {
     mMap?.addMarker(standartMarker)
   }
  }
  </code></pre>