安卓里面设置启动页

这里我们需要借助第三方的框架flutter_splash_screen来实现。具体步骤如下：
1、需要在pubspec.yaml文件里面添加依赖：

dependencies:
  flutter_splash_screen: ^xxx

2、通过flutter packages get来更新获取依赖包。
3、在安卓入口文件MainActivity.java里面添加如下代码：

package com.example.aethersharedcommunication;

import android.os.Bundle;
//导入我们引入的第三方框架
import org.devio.flutter.splashscreen.SplashScreen;

import androidx.annotation.NonNull;
//import android.support.annotation.NonNull;
import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.plugins.GeneratedPluginRegistrant;

public class MainActivity extends FlutterActivity {
  @Override
  public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
    GeneratedPluginRegistrant.registerWith(flutterEngine);
  }
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    //在此调用，实现引导页屏幕的显示
    SplashScreen.show(this, true);
    super.onCreate(savedInstanceState);
  }
}

4、在GeneratedPluginRegistrant文件里面需要注册我们使用到的中间件

package io.flutter.plugins;

import androidx.annotation.Keep;
import androidx.annotation.NonNull;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.embedding.engine.plugins.shim.ShimPluginRegistry;

/**
 * Generated file. Do not edit.
 * This file is generated by the Flutter tool based on the
 * plugins that support the Android platform.
 */
@Keep
public final class GeneratedPluginRegistrant {
  public static void registerWith(@NonNull FlutterEngine flutterEngine) {
    ShimPluginRegistry shimPluginRegistry = new ShimPluginRegistry(flutterEngine);
 //注册启动页需要用到的中间件    
 org.devio.flutter.splashscreen.FlutterSplashScreenPlugin.registerWith(shimPluginRegistry.registrarFor("org.devio.flutter.splashscreen.FlutterSplashScreenPlugin"));

      io.github.ponnamkarthik.toast.fluttertoast.FluttertoastPlugin.registerWith(shimPluginRegistry.registrarFor("io.github.ponnamkarthik.toast.fluttertoast.FluttertoastPlugin"));
    flutterEngine.getPlugins().add(new io.flutter.plugins.pathprovider.PathProviderPlugin());
    flutterEngine.getPlugins().add(new com.tekartik.sqflite.SqflitePlugin());
    flutterEngine.getPlugins().add(new io.flutter.plugins.webviewflutter.WebViewFlutterPlugin());
  }
}

5、然后创建一个launch_screen.xml文件放在/android/app/src/main/res/layout目录下，里面的内容如下：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <!--launch_icon是我们启动页的名字-->
    <ImageView android:layout_width="match_parent" android:layout_height="match_parent" 
android:src="@drawable/launch_icon" android:scaleType="centerCrop" />
</RelativeLayout>

6、然后需要在app/src/main/res/values文件夹下，新加一个colors.xml文件，这个文件主要是对状态栏的颜色进行设置，内容如下：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!--状态栏的颜色-->
    <color name="primary_dark">#000000</color>
</resources>

7、然后需要在app/src/main/res/values文件夹下，新加一个styles.xml文件，这个文件主要是对背景的颜色进行设置，内容如下

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
        <!-- Show a splash screen on the activity. Automatically removed when
             Flutter draws its first frame -->
        <item name="android:windowBackground">@drawable/launch_background</item>
        <!--设置透明背景-->
        <item name="android:windowIsTranslucent">true</item>
    </style>
</resources>

8、然后回到主页面的flutter代码，对启动页进行关闭，代码如下：

import 'dart:async';

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

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

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    super.initState();
    hideScreen();
  }

  ///hide your splash screen
  Future<void> hideScreen() async {
    Future.delayed(Duration(milliseconds: 3600), () {
      FlutterSplashScreen.hide();
    });
  }

iOS里面设置启动页

1、打开我们的flutter项目的iOS工程，如图所示：

1587349068985.jpg

2、将准备好的图片资源，按照如图所示的约束添加好，放入到LaunchScreen.storyboard里面

1587349132077.jpg
3、将图片的模式设置为Scale to Fill，如图所示：
1587349163728.jpg

到此，我们就已经将iOS和安卓的启动页设置OK。