title: Remove previous marker
body: <p>I am having a trouble. I am fetching my latitude and longitude in Realtime Firebase and created a marker but every time the latitude and longitude has an update it will create another marker.</p>
  
  <p>How can I delete the previous marker? Here is my code:</p>
  
  <pre><code>passRef = new Firebase(Config.FIREBASE_URL_PASSENGER);
  passRef.addValueEventListener(new ValueEventListener() {
      @Override
      public void onDataChange(DataSnapshot dataSnapshot) {
          for (DataSnapshot snapShot : dataSnapshot.getChildren()) {
              for (int cnt = 0; cnt &lt;= dataSnapshot.getChildrenCount(); cnt++) {
                  if (snapShot.child("latitude").exists() &amp;&amp; snapShot.child("longitude").exists() &amp;&amp; snapShot.child("destination").exists()) {
  
                      passUsername = snapShot.child("name").getValue().toString();
                      //getting the passenger's current location
                      locLatPass = Double.valueOf(snapShot.child("latitude").getValue().toString());
                      locLongPass = Double.valueOf(snapShot.child("longitude").getValue().toString());
                      latlngpass = new LatLng(locLatPass, locLongPass);
  
                      MarkerOptions passLocMarkerOptions = new MarkerOptions();
                      passLocMarkerOptions.position(latlngpass);
                      passLocMarkerOptions.title(passUsername+ "'s Location");
  
                      passLocMarkerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE));
                      passLocationMarker = mMap.addMarker(passLocMarkerOptions);
                  } else {
                  }
              }
              Toast.makeText(MapsActivity.this, "Passenger Username" + passUsername + " latitude" + locLatPass + "Longitude" + locLongPass, Toast.LENGTH_LONG).show();
          }
      }
  
      @Override
      public void onCancelled(FirebaseError firebaseError) {
  
      }
  });
  </code></pre>