export default class LoginScreen extends Component {
    constructor(props, context) {
        super(props, context);
        this.state = {username: '', password: '',spinnerVisible:false};
        this._event = this._event.bind(this);
        DeviceEventEmitter.addListener('EVENT_SHOW',this._event);
    }
    _event(event: Event){
        Alert.alert("Event handler","Event handler");
    }