<View style={styles.container}>
          <MapView style={styles.map}
             region={{
               latitude: this.state.latitude,
               longitude:this.state.longitude,
               latitudeDelta:0.1,
               longitudeDelta:0.1,
             }}

          >
            <Marker
              coordinate= {{
                latitude: 38.41885,
                longitude: 27.12872,
              }}
              title={'my marker'}
              description={'test'}
            />


        </MapView>
      </View>