如何从Firebase到Google Map检索数据? [英] How to retrieve data from firebase to google map?

问题描述

我正在尝试从Firebase到我的Google Map检索纬度和经度数据，但是当我运行该应用程序时，标记不会显示.

I am trying to retrieve latitude and longitude data from firebase to my google map, but when I run the application the marker won't show.

这是我的代码:

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
    private FirebaseDatabase tracker;
    private DatabaseReference databaseLocation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        tracker = FirebaseDatabase.getInstance();
        databaseLocation = tracker.getReference("lokasi3");

        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(final GoogleMap googleMap) {
        databaseLocation.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for (DataSnapshot child : dataSnapshot.child("lokasi3").getChildren()) {
                    Lokasi3 lokasi3 = dataSnapshot.getValue(Lokasi3.class);
                    String latitude = child.child("latitude").getValue().toString();
                    String longitude = child.child("longitude").getValue().toString();
                    double loclatitude = Double.parseDouble(latitude);
                    double loclongitude = Double.parseDouble(longitude);
                    LatLng cod = new LatLng(loclatitude, loclongitude);
                    googleMap.addMarker(new MarkerOptions().position(cod).title(""));
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }
}

推荐答案

在onCreate上监听您的数据

listen to your data in onCreate

 databaseLocation.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for (DataSnapshot child : dataSnapshot.child("lokasi3").getChildren()) {
            Lokasi3 lokasi3 = dataSnapshot.getValue(Lokasi3.class);
            String latitude = child.child("latitude").getValue().toString();
            String longitude = child.child("longitude").getValue().toString();
            double loclatitude = Double.parseDouble(latitude);
            double loclongitude = Double.parseDouble(longitude);
            LatLng cod = new LatLng(loclatitude, loclongitude);
            googleMap1.addMarker(new MarkerOptions().position(cod).title(""));
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {

    }


});





GoogleMap googleMap1;//make it global

@Override
public void onMapReady(final GoogleMap googleMap) {
    googleMap1=googleMap;

}

这篇关于如何从Firebase到Google Map检索数据?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！