splash_screen.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Overlay Example',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: SplashScreen(),
    );
  }
}

class SplashScreen extends StatefulWidget {
  @override
  _SplashScreenState createState() => _SplashScreenState();
}

class _SplashScreenState extends State<SplashScreen> {
  @override
  void initState() {
    super.initState();
    startTimeout();
  }

  startTimeout() {
    return Timer(Duration(seconds: 4), changeScreen);
  }

  changeScreen() async {
    Navigator.of(context).pushReplacement(
      CupertinoPageRoute(
        builder: (BuildContext context) => Scaffold(
          //remplacer par page suivante
          body: Center(
            child: Text('Welcome to home page'),
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        width: double.infinity,
        decoration: const BoxDecoration(
          image: DecorationImage(
            image: NetworkImage(
              'https://images.unsplash.com/photo-1602784648782-c9e96b8d29c9?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=334&q=80',
            ),
            fit: BoxFit.cover,
          ),
        ),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ClipRRect(
              borderRadius: BorderRadius.circular(60.0),
              child: Image.network(
                'https://upload.wikimedia.org/wikipedia/commons/0/08/Learn_area_logo.png',
                width: 96,
              ),
            ),
            SizedBox(height: 16.0),
            Text(
              "Lorem ipsum, dolor sit amet consectetur adipisicing elit.",
              textAlign: TextAlign.center,
              style: TextStyle(
                fontSize: 16.0,
                color: Colors.white,
              ),
            ),
          ],
        ),
      ),
    );
  }
}