Flutter图片缓存优化

import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
void main() {
  runApp(MyApp());
}
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(),
    );
  }
}
class MyHomePage extends StatelessWidget {
  final imageUrl = "https://picsum.photos/250?image=9";
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Demo'),
      ),
      body: Center(
        child: CachedNetworkImage(
          imageUrl: imageUrl,
          progressIndicatorBuilder: (context, url, downloadProgress) =>
              CircularProgressIndicator(value: downloadProgress.progress),
          errorWidget: (context, url, error) => Icon(Icons.error),
        ),
      ),
    );
  }
}