对于Android，转到这个路径，

Android > app > SRC > main > res > drawable > launcher_background.xml

默认代码为白色背景屏幕。 像这样,

<!-- You can insert your own image assets here -->
 <item>
    <bitmap
        android:gravity="center"
        android:src="@mipmap/launch_image" />
</item> 

您可以通过添加图标或任何自定义设计来更改它的颜色或修改它。更多的定制细节签出这为android。

为Ios

在Xcode中打开Ios项目。

选择Runner，然后。内部Runner文件夹Main。故事板文件在那里， 在这里输入图像描述

默认情况下，它的颜色是白色，你可以根据自己的要求自定义或改变颜色，更多的自定义检查这个Ios。

你应该试试下面的代码，为我工作

import 'dart:async';
import 'package:attendance/components/appbar.dart';
import 'package:attendance/homepage.dart';
import 'package:flutter/material.dart';

class _SplashScreenState extends State<SplashScreen>
with SingleTickerProviderStateMixin {


void handleTimeout() {
  Navigator.of(context).pushReplacement(new MaterialPageRoute(
    builder: (BuildContext context) => new MyHomePage()));
}

startTimeout() async {
  var duration = const Duration(seconds: 3);
  return new Timer(duration, handleTimeout);
}

@override
void initState() {
  // TODO: implement initState
  super.initState();

  _iconAnimationController = new AnimationController(
      vsync: this, duration: new Duration(milliseconds: 2000));

  _iconAnimation = new CurvedAnimation(
      parent: _iconAnimationController, curve: Curves.easeIn);
  _iconAnimation.addListener(() => this.setState(() {}));

  _iconAnimationController.forward();

  startTimeout();
}

@override
Widget build(BuildContext context) {
  return new Scaffold(
    body: new Scaffold(
      body: new Center(
        child: new Image(
        image: new AssetImage("images/logo.png"),
        width: _iconAnimation.value * 100,
        height: _iconAnimation.value * 100,
      )),
    ),
  );
}
}

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

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

最简单的方法是使用flutter_native_splash包

首先，把它添加到你的开发依赖项中:

dev_dependencies:
  flutter_native_splash: ^1.3.1 # make sure to us the latest version

现在，你可以配置你的启动画面你喜欢:

     flutter_native_splash:

      android: true # show for android, you may set it to false
      ios: true # show for IOS, you may set it to false

      image: assets\logo.png # the default image for light and dark themes. Until now, images should be png images
      image_dark: aassets\logo_dark.png # It will override the 'image' in the dark mode

      color: "#ffffff" # the default color for light and dark themes
      color_dark: "#0a0a0a" # will override the 'color' in the dark mode

      android_gravity: fill # make the image fill the screen for android
      ios_content_mode: scaleAspectFill # make the image fill the screen for android

这样做之后，运行:

flutter clean && flutter pub get && flutter pub run flutter_native_splash:create

你会注意到的。“\android\app\src\main\res*”已经改变，并添加了新的启动画面。