react-native maps not loading for android (blank map)

Give style to MapView.

Include

var { width, height } = Dimensions.get('window')

in render method

<View style={styles.container}>
        <MapView style = {styles.mapcontainer}
          showsUserLocation={true}
          showsMyLocationButton={false}
          zoomEnabled = {true}
          region={this.state.region} >
        </MapView>
</View>

Include style

container: {
    flex: 1,
  },
mapcontainer: {
    flex: 1,
    width: width,
    height: height,
  },