// 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 'package:flutter/material.dart'; import 'package:flutter/scheduler.dart'; import 'package:flutter/services.dart'; import 'package:flutter_test/flutter_test.dart' show collectAllElementsFrom; import '../common.dart'; const int _kNumIters = 10000; Future<void> main() async { assert(false, "Don't run benchmarks in debug mode! Use 'flutter run --release'."); runApp(MaterialApp( home: Scaffold( body: GridView.count( crossAxisCount: 5, children: List<Widget>.generate(25, (int index) { return Center( child: Scaffold( appBar: AppBar( title: Text('App $index'), actions: const <Widget>[ Icon(Icons.help), Icon(Icons.add), Icon(Icons.ac_unit), ], ), body: const Column( children: <Widget>[ Text('Item 1'), Text('Item 2'), Text('Item 3'), Text('Item 4'), ], ), ), ); }), ), ), )); // Lists may not be scrolled into frame in landscape. SystemChrome.setPreferredOrientations(<DeviceOrientation>[ DeviceOrientation.portraitUp, DeviceOrientation.portraitDown, ]); // Wait for frame rendering to stabilize. for (int i = 0; i < 5; i++) { await SchedulerBinding.instance.endOfFrame; } final Stopwatch watch = Stopwatch(); print('flutter_test allElements benchmark... (${WidgetsBinding.instance.rootElement})'); // Make sure we get enough elements to process for consistent benchmark runs int elementCount = collectAllElementsFrom(WidgetsBinding.instance.rootElement!, skipOffstage: false).length; while (elementCount < 2458) { await Future<void>.delayed(Duration.zero); elementCount = collectAllElementsFrom(WidgetsBinding.instance.rootElement!, skipOffstage: false).length; } print('element count: $elementCount'); watch.start(); for (int i = 0; i < _kNumIters; i += 1) { final List<Element> allElements = collectAllElementsFrom( WidgetsBinding.instance.rootElement!, skipOffstage: false, ).toList(); allElements.clear(); } watch.stop(); final BenchmarkResultPrinter printer = BenchmarkResultPrinter(); printer.addResult( description: 'All elements iterate', value: watch.elapsedMicroseconds / _kNumIters, unit: 'µs per iteration', name: 'all_elements_iteration', ); printer.printToStdout(); }