index.android.js

//#region Imports
import React, { Component } from "react";
import {
  AppRegistry,
  StyleSheet,
  Text,
  TextInput,
  View,
  BackHandler
} from "react-native";
import firebase from "firebase";
import { Actions } from "react-native-router-flux";
import Toast from "react-native-simple-toast";
import NewBG from "./app/Components/NewBG";
import LoginForm from "./app/Components/LoginForm";
import Bglst from "./app/Components/BgLst";
import Router from "./app/Router";
//#endregion

export default class DiabetesJournal extends Component {
  constructor(props) {
    super(props);
    this.state = {
      isLoggedIn: false,
      Exitcount: 0
    };
  }

  componentWillMount() {
    if (!firebase.apps.length) {
      firebase.initializeApp({
        apiKey: "AIzaSyBgwVLxWeradAHjqw-5rMvLZ2_2NoZ0nKA",
        authDomain: "diabetesjournal-405cf.firebaseapp.com",
        databaseURL: "https://diabetesjournal-405cf.firebaseio.com",
        projectId: "diabetesjournal-405cf",
        storageBucket: "diabetesjournal-405cf.appspot.com",
        messagingSenderId: "750281915622"
      });
    }
    firebase.auth().onAuthStateChanged(user => {
      if (user) {
        this.setState({ isLoggedIn: true });
        Actions.BG();
      } else {
        this.setState({ isLoggedIn: false });
        Actions.auth();
      }
    });
    BackHandler.removeEventListener("hardwareBackPress", this.onBackPress);
  }

  componentDidMount() {
    BackHandler.addEventListener(
      "hardwareBackPress",
      this.onBackPress.bind(this)
    );
  }
  onBackPress() {
    if (Actions.state.index === 0) {
      return false;
    }
    if (Actions.currentScene === "_bglst") {
      this.setState({ Exitcount: this.state.Exitcount + 1 });
     
      if (this.state.Exitcount <= 1) {
        Toast.show("Press One More Time To Exit", Toast.SHORT);
      }
      
      if (this.state.Exitcount > 1) {
        this.state.Exitcount = 0;
        return false;
      }
      
    } else {
      Actions.pop();
      return true;
    }
    return true
  }

  CompnentSelector(self) {
    if (self.state.isLoggedIn) {
      return (
        <View>
          <Header Headertxt={"BG Journal"} />
          <Bglst />
        </View>
      );
    } else {
      return (
        <View>
          <LoginForm />
        </View>
      );
    }
  }

  render() {
    return (
      <View style={{ flex: 1 }}>
        <Router />
      </View>
    );
  }
}

AppRegistry.registerComponent("DiabetesJournal", () => DiabetesJournal);