Flutter FadeInImage

动图录制所以图片有闪动，实际效果正常。

1.首先需要在目录在创建assets文件夹，用于存放资源文件。（loading.gif）

2.修改pubspec.yaml

assets:
    -  assets/loading.gif

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: FadeInImage.assetNetwork(
            placeholder: "assets/loading.gif",
            image: "https://tukuimg.bdstatic.com/scrop/6be65a47b2bc49e492385b8ebc486d14.gif"),
      ),
    );
  }
}