Question

我想通过单击来从Firebase检索多个LatLng实际上我是从firebase提取单个LatLng。如何获取plz告诉我这是地图活动代码

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

    DatabaseReference databaseReference= FirebaseDatabase.getInstance().getReference("Location");

    ValueEventListener listener = databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            Double latitude=dataSnapshot.child("latitude").getValue(Double.class);
            Double longitude=dataSnapshot.child("longitude").getValue(Double.class);

            LatLng location = new LatLng(latitude,longitude);

            // Add a marker in Lahore and move the camera
          //  LatLng Lahore = new LatLng(31.588048, 74.315097);
            //Different Map types
            //mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
            //mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
            //mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);
            //mMap.setMapType(GoogleMap.MAP_TYPE_NONE);
            mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
            mMap.addMarker(new MarkerOptions().position(location).title("Shahi Qila"));
            mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(location,15.2f));
           // mMap.setMyLocationEnabled(true);
            // mMap.moveCamera(CameraUpdateFactory.newLatLng(Lahore));
            //zoom
    /*
    CameraUpdate zoom= CameraUpdateFactory.zoomTo(20);
    mMap.moveCamera(zoom);
    mMap.animateCamera(zoom);*/

        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });

这是数据库结构

database structure

Answer 1

您的代码可以，但是您必须检查

中接收的数据

onDataChange

带有调试点。

并说说您运行应用程序时会发生什么在评论中更新我

Answer 2

首先创建模型以直接解析数据

public class MyLocation {
    String des;
    double latitude, longitude;

    public String getDes() {
        return des;
    }

    public void setDes(String des) {
        this.des = des;
    }

    public Long getLatitude() {
        return latitude;
    }

    public void setLatitude(Long latitude) {
        this.latitude = latitude;
    }

    public Long getLongitude() {
        return longitude;
    }

    public void setLongitude(Long longitude) {
        this.longitude = longitude;
    }
}

然后像下面一样在DatabaseReference上进行查询以获取数据

DatabaseReference databaseReference= FirebaseDatabase.getInstance().getReference();

ValueEventListener listener = databaseReference.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
        for(DataSnapshot locationSnapshot: dataSnapshot.getChildren()) {

            MyLocation myLocation = locationSnapshot.getValue(MyLocation.class);

            LatLng location = new LatLng(myLocation.getLatitude(), myLocation.getLongitude());
            mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
            mMap.addMarker(new MarkerOptions().position(location).title("Shahi Qila"));
            mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(location, 15.2f));
        }

    }
});

从Firebase数据库检索多个纬度经度

2 个答案: