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ab2b0851a2
This adds a smoke test for every single API example. It also fixes 17 tests that had bugs in them, or were otherwise broken, and even fixes one actual bug in the framework, and one limitation in the framework. The bug in the framework is that NetworkImage's _loadAsync method had await response.drain<List<int>>();, but if the response is null, it will throw a cryptic exception saying that Null can't be assigned to List<int>. The fix was just to use await response.drain<void>(); instead. The limitation is that RelativePositionedTransition takes an Animation<Rect> rect parameter, and if you want to use a RectTween with it, the value emitted there is Rect?, and one of the examples was just casting from Animation<Rect> to Animation<Rect?>, which is invalid, so I modified RelativePositionedTransition to take a Rect? and just use Rect.zero if the rect is null.
89 lines
3.3 KiB
Dart
89 lines
3.3 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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// Template: dev/snippets/config/templates/freeform.tmpl
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//
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// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
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// of samples, and may be ignored if you are just exploring the sample.
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// Flutter code sample for BuildOwner
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//
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//***************************************************************************
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//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
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// This example shows how to build an off-screen widget tree used to measure
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// the layout size of the rendered tree. For some use cases, the simpler
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// [Offstage] widget may be a better alternative to this approach.
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//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
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//***************************************************************************
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//****************************************************************************
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//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
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import 'package:flutter/material.dart';
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import 'package:flutter/rendering.dart';
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import 'package:flutter/widgets.dart';
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//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
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//****************************************************************************
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//********************************************************************
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//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
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void main() {
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WidgetsFlutterBinding.ensureInitialized();
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final Size size = measureWidget(const SizedBox(width: 640, height: 480));
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// Just displays the size calculated above.
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runApp(
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WidgetsApp(
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title: 'BuildOwner Sample',
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color: const Color(0xff000000),
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builder: (BuildContext context, Widget? child) {
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return Scaffold(
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body: Center(
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child: Text(size.toString()),
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),
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);
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},
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),
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);
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}
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Size measureWidget(Widget widget) {
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final PipelineOwner pipelineOwner = PipelineOwner();
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final MeasurementView rootView = pipelineOwner.rootNode = MeasurementView();
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final BuildOwner buildOwner = BuildOwner(focusManager: FocusManager());
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final RenderObjectToWidgetElement<RenderBox> element = RenderObjectToWidgetAdapter<RenderBox>(
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container: rootView,
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debugShortDescription: '[root]',
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child: widget,
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).attachToRenderTree(buildOwner);
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try {
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rootView.scheduleInitialLayout();
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pipelineOwner.flushLayout();
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return rootView.size;
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} finally {
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// Clean up.
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element.update(RenderObjectToWidgetAdapter<RenderBox>(container: rootView));
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buildOwner.finalizeTree();
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}
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}
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class MeasurementView extends RenderBox with RenderObjectWithChildMixin<RenderBox> {
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@override
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void performLayout() {
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assert(child != null);
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child!.layout(const BoxConstraints(), parentUsesSize: true);
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size = child!.size;
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}
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@override
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void debugAssertDoesMeetConstraints() => true;
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}
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//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
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//********************************************************************
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