title: How to addMarker directly on GoogleMap after click button setMyLocationEnabled?
body: <p>I made a code.
  In this code, when i click a map, there will be  a marker on clicked point. </p>
  
  <p><strong>This is my Code</strong></p>
  
  <pre><code>public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
  
      private GoogleMap mMap;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_maps);
          SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                  .findFragmentById(R.id.map);
          mapFragment.getMapAsync(this);
      }
  
      @Override
      public void onMapReady(final GoogleMap googleMap) {
          mMap = googleMap;
          if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                  == PackageManager.PERMISSION_GRANTED) {
              mMap.setMyLocationEnabled(true);
          } else {
              Toast.makeText(getApplicationContext(), "oh, no", Toast.LENGTH_LONG).show();
          }
          googleMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
              @Override
              public void onMapClick(LatLng point) {
                  String lat = String.valueOf(point.latitude);
                  String lng = String.valueOf(point.longitude);
                  MarkerOptions marker = new MarkerOptions().position(
                          new LatLng(point.latitude, point.longitude)).title("ok");
                  mMap.addMarker(marker);
              }
          });
      }
  }
  </code></pre>
  
  <p><strong>Question :</strong> 
  What i want is that when i click SetMylocationEnable button, there also added a new marker. And because i want marker is only one in whole map, another marker that has been in the map before is to be removed. How can i do it? Would you teach me?</p>
  
  <p>You can see what button i saying is, in picture. (picture is from : <a href="https://stackoverflow.com/questions/27010991/enable-my-location-icon-googlemap-v2">Enable my location icon Googlemap v2</a>)</p>
  
  <p><a href="https://i.stack.imgur.com/upyfe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/upyfe.png" alt="enter image description here"></a></p>