flutter添加啟動圖及設置啟動時間

首先貼個官方的設置方法，看這里：https://flutterchina.club/assets-and-images/#%E6%9B%B4%E6%96%B0%E5%90%AF%E5%8A%A8%E9%A1%B5
雖然官方的方法比較簡單，但是有時我們可能需要自己配置啟動圖的生效時間，這時就需要另外實現了。思路就是第一個頁面放一張全屏圖片，倒數計時結束時再跳轉到主頁：

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

void main() {
  runApp(new MaterialApp(
    title: '啟動圖demo',
    theme: new ThemeData(
        brightness: Brightness.light,
        backgroundColor: Colors.white,
        platform: TargetPlatform.iOS),
    home: new SplashScreen(),
    routes: <String, WidgetBuilder>{
      '/home': (BuildContext context) => new Home()
    },
  ));
}

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

class _SplashScreenState extends State<SplashScreen> {
  startTime() async {
    //設置啟動圖生效時間
    var _duration = new Duration(seconds: 1);
    return new Timer(_duration, navigationPage);
  }

  void navigationPage() {
    Navigator.of(context).pushReplacementNamed('/home');
  }

  @override
  void initState() {
    super.initState();
    startTime();
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: new Center(
        child: new Image.asset('assets/images/launch_image.png'),
      ),
    );
  }
}

最后記得將啟動圖在pubspec.yaml文件聲明下，完畢~