Hero指的是可以在路由(页面)之间“飞行”的widget。
使用Flutter的Hero widget创建hero动画。
将 hero从一个路由飞到另一个路由。

a.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之Hero动画',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  void showPhoto(BuildContext context, Widget image) {
    Navigator.push(context,
        MaterialPageRoute<void>(builder: (BuildContext context) {
      return GestureDetector(
        child: SizedBox.expand(
          child: Hero(
            tag: image,
            child: image,
          ),
        ),
        onTap: () {
          Navigator.maybePop(context);
        },
      );
    }));
  }

  List<Widget> _list = <Widget>[
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
    ClipRRect(
      child: Image.asset(
        'images/hanyun.jpg',
        fit: BoxFit.cover,
      ),
      borderRadius: BorderRadius.circular(8),
    ),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text('flutter之Hero动画'),
        centerTitle: true,
      ),
      body: GridView.count(
        crossAxisCount: 3,
        mainAxisSpacing: 4.0,
        crossAxisSpacing: 4.0,
        padding: const EdgeInsets.all(4.0),
        children: _list.map(
          (Widget img) {
            return GestureDetector(
              onTap: () {
                showPhoto(context, img);
              },
              child: Hero(
                tag: img,
                child: img,
              ),
            );
          },
        ).toList(),
      ),
    );
  }
}