GeoQuery方法中的空点异常

Question

我已经编写了一些代码来从geoQuery和GeoFencing获取通知，但是在某些时候我遇到了一些例外。 我尝试了很多方法来摆脱这种情况，但一切都失败了。 这是我得到空指针异常的代码

GeoQuery geoQuery = geoFire.queryAtLocation(new GeoLocation(start_Point.latitude, start_Point.longitude), 0.05f);
        geoQuery.addGeoQueryEventListener(new GeoQueryEventListener() {
            @Override
            public void onKeyEntered(String key, GeoLocation location) {
                SendNotification("Child", String.format("%s reached to school", key));
            }

            @Override
            public void onKeyExited(String key) {

                SendNotification("Child", String.format("%s went out from school", key));
            }

            @Override
            public void onKeyMoved(String key, GeoLocation location) {
                Log.d("MOVE", String.format("%s Child is on his Way [%f / %f]", key, location.latitude, location.longitude) );
            }

            @Override
            public void onGeoQueryReady() {

            }

            @Override
            public void onGeoQueryError(DatabaseError error) {
                Log.e("Error" , ""+ error);
            }
        });
GeoQuery endPoint = geoFire.queryAtLocation(new GeoLocation(31.8020471, 74.2594809), 0.05f);
        endPoint.addGeoQueryEventListener(new GeoQueryEventListener() {
            @Override
            public void onKeyEntered(String key, GeoLocation location) {
                SendNotification("Child", String.format("%s reached to home", key));
            }

            @Override
            public void onKeyExited(String key) {
                SendNotification("Child", String.format("%s went out from home", key));
            }

            @Override
            public void onKeyMoved(String key, GeoLocation location) {

            }

            @Override
            public void onGeoQueryReady() {

            }

            @Override
            public void onGeoQueryError(DatabaseError error) {

            }
        });

这是我的LogCat

Process: com.softtech.aqeel.childsequrity, PID: 4167
java.lang.NullPointerException: Attempt to invoke virtual method 'com.firebase.geofire.GeoQuery com.firebase.geofire.GeoFire.queryAtLocation(com.firebase.geofire.GeoLocation, double)' on a null object reference
    at com.softtech.aqeel.childsequrity.GoogleMaps$3.Map(GoogleMaps.java:281)
    at com.softtech.aqeel.childsequrity.GoogleMaps$3.run(GoogleMaps.java:233)
    at com.softtech.aqeel.childsequrity.GoogleMaps.startRepeating(GoogleMaps.java:225)
    at com.softtech.aqeel.childsequrity.GoogleMaps.onMapReady(GoogleMaps.java:152)
    at com.google.android.gms.maps.zzak.zza(Unknown Source:7)
    at com.google.android.gms.maps.internal.zzaq.dispatchTransaction(Unknown Source:31)
    at com.google.android.gms.internal.maps.zzb.onTransact(Unknown Source:22)
    at android.os.Binder.transact(Binder.java:604)