title: How to retrieve data from Firebase to make multiple Markers on map Android
body: <p>this is my firebase look like</p>
  
  <p><a href="https://imgur.com/a/hkmqatV" rel="nofollow noreferrer">firebase</a>.</p>
  
  <p>And this my maps activity :</p>
  
  <pre><code>public class MapsActivity extends FragmentActivity implements OnMapReadyCallback{
      private GoogleMap mMap;
      private DatabaseReference mUsers;
      Marker marker;
      public static final String FIREBASE_URL = "https://xxx.firebaseio.com/";
      private Firebase firebase;
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_maps);
  // Obtain the SupportMapFragment and get notified when the map is ready to be used.
          Firebase.setAndroidContext(this);
          firebase = new Firebase(FIREBASE_URL);
          SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                  .findFragmentById(R.id.map);
          mapFragment.getMapAsync(this);
  
      }
  
      @Override
      public void onMapReady(final GoogleMap googleMap) {
          firebase.addListenerForSingleValueEvent(new ValueEventListener() {
              @Override
              public void onDataChange(com.firebase.client.DataSnapshot dataSnapshot) {
                  for (com.firebase.client.DataSnapshot s : dataSnapshot.child("marker").getChildren()) {
                      String lat = s.child("lat").getValue().toString();
                      String lng = s.child("lng").getValue().toString();
  
                      double latitude = Double.parseDouble(lat);
                      double longitude = Double.parseDouble(lng);
                      LatLng loc = new LatLng(latitude, longitude);
                      googleMap.addMarker(new MarkerOptions().position(loc).title(s.child("nama").getValue().toString()));
                  }
              }
  
              @Override
              public void onCancelled(FirebaseError firebaseError) {
  
              }
          });
  
      }
  }
  </code></pre>
  
  <p>and the error says</p>
  
  <pre><code>E/MarketPageConfiguration: parse page configuration json error
      org.json.JSONException: No value for homeIndex
  </code></pre>
  
  <p>and when i run it, it doesn't show the marker and the location still get wrong. I think i name it wrong about the "child" and get value in it, but i have no idea how to figure it out.</p>
  
  <p>(the url link is all right)</p>