examples/image_list/lib/main.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';
import 'dart:io';
import 'dart:math';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart' show rootBundle;
import 'package:flutter/services.dart';

/// An example that sets up local http server for serving single
/// image, creates single flutter widget with five copies of requested
/// image and prints how long the loading took.
///
/// This is used in [$FH/flutter/devicelab/bin/tasks/image_list_reported_duration.dart] test.
///
String certificate = '''
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
''';

String privateKey = '''
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
''';

class MyHttpOverrides extends HttpOverrides {
  @override
  HttpClient createHttpClient(SecurityContext context) {
    return super.createHttpClient(
        (context ?? SecurityContext())..setTrustedCertificatesBytes(certificate.codeUnits)
    );
  }
}

Future<void> main() async {
  HttpOverrides.global = MyHttpOverrides();

  final SecurityContext serverContext = SecurityContext()
    ..useCertificateChainBytes(certificate.codeUnits)
    ..usePrivateKeyBytes(privateKey.codeUnits);

  final HttpServer httpServer =
      await HttpServer.bindSecure('localhost', 0, serverContext);
  final int port = httpServer.port;
  print('Listening on port $port.');

  // Initializes bindings before using any platform channels.
  WidgetsFlutterBinding.ensureInitialized();
  final ByteData byteData = await rootBundle.load('images/coast.jpg');
  httpServer.listen((HttpRequest request) async {
    const int chunk_size = 2048;
    int offset = byteData.offsetInBytes;
    while (offset < byteData.lengthInBytes) {
      final int length = min(byteData.lengthInBytes - offset, chunk_size);
      final Uint8List bytes = byteData.buffer.asUint8List(offset, length);
      offset += length;
      request.response.add(bytes);
      // Let other isolates and microtasks to run.
      await Future<void>.delayed(const Duration());
    }
    request.response.close();
  });

  runApp(MyApp(port));
}

const int IMAGES = 50;

@immutable
class MyApp extends StatelessWidget {
  const MyApp(this.port);

  final int port;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page', port: port),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key key, this.title, this.port}) : super(key: key);
  final String title;
  final int port;

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

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  Widget createImage(final int index, final Completer<bool> completer) {
    return Image.network(
        'https://localhost:${widget.port}/${_counter * IMAGES + index}',
        frameBuilder: (
          BuildContext context,
          Widget child,
          int frame,
          bool wasSynchronouslyLoaded,
        ) {
          if (frame == 0 && !completer.isCompleted) {
            completer.complete(true);
          }
          return child;
        },
    );
  }

  @override
  Widget build(BuildContext context) {
    final List<AnimationController> controllers = List<AnimationController>(IMAGES);
    for (int i = 0; i < IMAGES; i++) {
      controllers[i] = AnimationController(
        duration: const Duration(milliseconds: 3600),
        vsync: this,
      )..repeat();
    }
    final List<Completer<bool>> completers = List<Completer<bool>>(IMAGES);
    for (int i = 0; i < IMAGES; i++) {
      completers[i] = Completer<bool>();
    }
    final List<Future<bool>> futures = completers.map(
        (Completer<bool> completer) => completer.future).toList();
    final DateTime started = DateTime.now();
    Future.wait(futures).then((_) {
      print(
          '===image_list=== all loaded in ${DateTime.now().difference(started).inMilliseconds}ms.');
    });
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Row(children: createImageList(IMAGES, completers, controllers)),
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }

  List<Widget> createImageList(int count, List<Completer<bool>> completers,
      List<AnimationController> controllers) {
    final List<Widget> list = <Widget>[];
    for (int i = 0; i < count; i++) {
      list.add(Flexible(
          fit: FlexFit.tight,
          flex: i + 1,
          child: RotationTransition(
              turns: controllers[i],
              child: createImage(i + 1, completers[i]))));
    }
    return list;
  }
}