content: import 'package:flutter/material.dart';
  
  import 'YoYoPlayerScreen.dart';
  
  void main() =>
      runApp(MaterialApp(debugShowCheckedModeBanner: false, home: MyApp()));
  
  class MyApp extends StatefulWidget {
    @override
    _MyAppState createState() => _MyAppState();
  }
  
  class _MyAppState extends State<MyApp> {
    bool fullscreen = false;
  
    @override
    Widget build(BuildContext context) {
      return Scaffold(
          appBar: fullscreen == false
              ? AppBar(
                  backgroundColor: Colors.blue,
                  title: Image(
                    image: AssetImage('image/yoyo_logo.png'),
                    fit: BoxFit.fitHeight,
                    height: 50,
                  ),
                  centerTitle: true,
                )
              : null,
          body: Column(
            children: [
              TextButton(
                  onPressed: () {
                    Navigator.push(
                        context,
                        MaterialPageRoute(
                            builder: (context) => YoYoPlayerScreen()));
                  },
                  child: Text("play"))
            ],
          ));
    }
  }
  