main.dart

import 'package:flutter/material.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
import 'package:lecturescanner/loginWidget.dart';

void main() => runApp(lecturescanner());

class lecturescanner extends StatelessWidget
{
  @override
  Widget build(BuildContext context)
  {
    return new MaterialApp
      (
      title: "Сканнер відвідування",
      theme: ThemeData (primarySwatch: Colors.lightGreen),
      home: MainPage()
      );
  }
}


class MainPage extends StatefulWidget {
  @override
  _MainPageState createState() => _MainPageState();
}

class _MainPageState extends State<MainPage> {

  SharedPreferences sharedPreferences;

  @override
  void initState() {
    super.initState();
    checkLoginStatus();
  }

  checkLoginStatus() async {
    sharedPreferences = await SharedPreferences.getInstance();
    if(sharedPreferences.getString("token") == null)
    {
      Navigator.of(context).pushAndRemoveUntil(MaterialPageRoute(builder: (BuildContext context) => LoginPage()), (Route<dynamic> route) => false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Login", style: TextStyle(color: Colors.white)),
        actions: <Widget>[
          FlatButton(
            onPressed: () {
              sharedPreferences.clear();
              sharedPreferences.commit();
              Navigator.of(context).pushAndRemoveUntil(MaterialPageRoute(builder: (BuildContext context) => LoginPage()), (Route<dynamic> route) => false);
            },
            child: Text("Log Out", style: TextStyle(color: Colors.white)),
          ),
        ],
      ),
      body: Center(child: Text("Main Page")),
      drawer: Drawer(),
    );
  }
}