react-native-google-signin platforms android null code example
Example: login with gmail in react native
import { GoogleSignin, GoogleSigninButton } from 'react-native-google-signin'; render() { <GoogleSigninButton style={{ width: 192, height: 48 }} size={GoogleSigninButton.Size.Wide} color={GoogleSigninButton.Color.Dark} onPress={this._signIn} disabled={this.state.isSigninInProgress} />}