如果有人在应用验证答案后发现图像不存在，请确保您添加的是@mipmap/ic_launcher而不是@mipmap/ic_launcher .png

这是在Flutter中添加动态启动画面的最佳方法。

主要。飞镖

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

void main() => runApp(MaterialApp(
      title: 'GridView Demo',
      home: SplashScreen(),
      theme: ThemeData(
        primarySwatch: Colors.red,
        accentColor: Color(0xFF761322),
      ),
      routes: <String, WidgetBuilder>{
        SPLASH_SCREEN: (BuildContext context) => SplashScreen(),
        HOME_SCREEN: (BuildContext context) => BasicTable(),
        //GRID_ITEM_DETAILS_SCREEN: (BuildContext context) => GridItemDetails(),
      },
    ));

SPLASHSCREEN。飞镖

import 'dart:async';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:app_example/constants.dart';


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

class SplashScreenState extends State<SplashScreen>
    with SingleTickerProviderStateMixin {
  var _visible = true;

  AnimationController animationController;
  Animation<double> animation;

  startTime() async {
    var _duration = new Duration(seconds: 3);
    return new Timer(_duration, navigationPage);
  }

  void navigationPage() {
    Navigator.of(context).pushReplacementNamed(HOME_SCREEN);
  }

@override
dispose() {
  animationController.dispose();  
  super.dispose();
}

  @override
  void initState() {
    super.initState();
    animationController = new AnimationController(
      vsync: this,
      duration: new Duration(seconds: 2),
    );
    animation =
        new CurvedAnimation(parent: animationController, curve: Curves.easeOut);

    animation.addListener(() => this.setState(() {}));
    animationController.forward();

    setState(() {
      _visible = !_visible;
    });
    startTime();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        fit: StackFit.expand,
        children: <Widget>[
          new Column(
            mainAxisAlignment: MainAxisAlignment.end,
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              Padding(
                padding: EdgeInsets.only(bottom: 30.0),
                child: new Image.asset(
                  'assets/images/powered_by.png',
                  height: 25.0,
                  fit: BoxFit.scaleDown,
                ),
              )
            ],
          ),
          new Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              new Image.asset(
                'assets/images/logo.png',
                width: animation.value * 250,
                height: animation.value * 250,
              ),
            ],
          ),
        ],
      ),
    );
  }
}

常量。飞镖

String SPLASH_SCREEN='SPLASH_SCREEN';
String HOME_SCREEN='HOME_SCREEN';

主屏幕。飞镖

import 'package:flutter/material.dart';

class BasicTable extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("Table Widget")),
      body: Center(child: Text("Table Widget")),
    );
  }
}

Flutter实际上为我们的应用程序添加启动画面提供了一种更简单的方法。 我们首先需要像设计其他应用程序屏幕一样设计一个基本页面。您需要将其设置为StatefulWidget，因为它的状态将在几秒钟内发生变化。

import 'dart:async';
import 'package:flutter/material.dart';
import 'home.dart';

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

class _SplashScreenState extends State<SplashScreen> {
  @override
  void initState() {
    super.initState();
    Timer(
        Duration(seconds: 3),
        () => Navigator.of(context).pushReplacement(MaterialPageRoute(
            builder: (BuildContext context) => HomeScreen())));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: Center(
        child: Image.asset('assets/splash.png'),
      ),
    );
  }
}

逻辑 在initState()中，调用一个Timer()，如你所愿，我设置为3秒，完成后将导航器推到应用程序的主屏幕。

注意:应用程序应该只显示一次启动画面，用户不应该在返回按钮按下时再次返回。为此，我们使用Navigator.pushReplacement()，它将移动到一个新屏幕，并从导航历史堆栈中删除前一个屏幕。

要更好地了解，请访问Flutter:设计您自己的启动画面

添加如下所示的页面和路由可能会有所帮助

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutkart/utils/flutkart.dart';
import 'package:flutkart/utils/my_navigator.dart';

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

class _SplashScreenState extends State<SplashScreen> {
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    Timer(Duration(seconds: 5), () => MyNavigator.goToIntro(context));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        fit: StackFit.expand,
        children: <Widget>[
          Container(
            decoration: BoxDecoration(color: Colors.redAccent),
          ),
          Column(
            mainAxisAlignment: MainAxisAlignment.start,
            children: <Widget>[
              Expanded(
                flex: 2,
                child: Container(
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: <Widget>[
                      CircleAvatar(
                        backgroundColor: Colors.white,
                        radius: 50.0,
                        child: Icon(
                          Icons.shopping_cart,
                          color: Colors.greenAccent,
                          size: 50.0,
                        ),
                      ),
                      Padding(
                        padding: EdgeInsets.only(top: 10.0),
                      ),
                      Text(
                        Flutkart.name,
                        style: TextStyle(
                            color: Colors.white,
                            fontWeight: FontWeight.bold,
                            fontSize: 24.0),
                      )
                    ],
                  ),
                ),
              ),
              Expanded(
                flex: 1,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: <Widget>[
                    CircularProgressIndicator(),
                    Padding(
                      padding: EdgeInsets.only(top: 20.0),
                    ),
                    Text(
                      Flutkart.store,
                      softWrap: true,
                      textAlign: TextAlign.center,
                      style: TextStyle(
                          fontWeight: FontWeight.bold,
                          fontSize: 18.0,
                          color: Colors.white),
                    )
                  ],
                ),
              )
            ],
          )
        ],
      ),
    );
  }
}

如果你想坚持到底，请参见: https://www.youtube.com/watch?v=FNBuo-7zg2Q

有两种方法

转到本机包和初始页面。就像在原生Android包中创建一个drawable 创建一个省道屏幕来显示一段时间

我在这里找到了关于移除白屏和显示启动画面的完整解释

SplashScreen(
          seconds: 3,
          navigateAfterSeconds: new MyApp(),
          // title: new Text(
          //   'Welcome In SplashScreen',
          //   style: new TextStyle(fontWeight: FontWeight.bold, fontSize: 20.0),
          // ),
          image: new Image.network('https://upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Tesla_Motors.svg/1200px-Tesla_Motors.svg.png'),
          backgroundColor: Colors.white,
          styleTextUnderTheLoader: new TextStyle(),
          photoSize: 150.0,
          loaderColor: Colors.black),
    ),
  );