57 lines
1.6 KiB
Dart
57 lines
1.6 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'dart:async';
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import 'dart:math';
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import 'package:flutter/material.dart';
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import 'package:flutter/scheduler.dart';
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import 'package:flutter_driver/driver_extension.dart';
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/// This application shows empty screen until first frame timings are acquired.
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void main() {
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enableFlutterDriverExtension();
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final completer = Completer<List<FrameTiming>>();
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SchedulerBinding.instance.addTimingsCallback((List<FrameTiming> timings) {
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completer.complete(timings);
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});
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runApp(
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Directionality(
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textDirection: TextDirection.ltr,
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child: _FirstFrameTimings(completer: completer),
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),
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);
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}
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class _FirstFrameTimings extends StatefulWidget {
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const _FirstFrameTimings({required this.completer});
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final Completer<List<FrameTiming>> completer;
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@override
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_FirstFrameTimingsState createState() => _FirstFrameTimingsState();
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}
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class _FirstFrameTimingsState extends State<_FirstFrameTimings> {
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int? _minFrameNumber;
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@override
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Widget build(BuildContext context) {
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widget.completer.future.then(_setMinFrameNumber);
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if (_minFrameNumber != null) {
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return Text(_minFrameNumber.toString(), key: const Key('minFrameNumber'));
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} else {
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return const Text('Waiting...');
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}
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}
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void _setMinFrameNumber(List<FrameTiming> timings) {
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final int minFrameNumber = timings.map((FrameTiming timing) => timing.frameNumber).reduce(min);
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setState(() {
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_minFrameNumber = minFrameNumber;
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});
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}
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}
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