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// 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.
// @dart = 2.8
import 'package:flutter_test/flutter_test.dart';
import 'package:flutter/material.dart';
// This is a regression test for https://github.com/flutter/flutter/issues/10549
// which was failing because _SliverPersistentHeaderElement.visitChildren()
// didn't check child != null before visiting its child.
class MySliverPersistentHeaderDelegate extends SliverPersistentHeaderDelegate {
@override
double get minExtent => 50.0;
@override
double get maxExtent => 150.0;
@override
Widget build(BuildContext context, double shrinkOffset, bool overlapsContent) => const Placeholder(color: Colors.teal);
@override
bool shouldRebuild(covariant SliverPersistentHeaderDelegate oldDelegate) => false;
}
class MyHomePage extends StatefulWidget {
const MyHomePage({ Key key }) : super(key: key);
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
static const int tabCount = 3;
TabController tabController;
@override
void initState() {
super.initState();
tabController = TabController(initialIndex: 0, length: tabCount, vsync: this);
}
@override
void dispose() {
tabController.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
bottom: TabBar(
controller: tabController,
tabs: List<Widget>.generate(tabCount, (int index) => Tab(text: 'Tab $index')).toList(),
),
),
body: TabBarView(
controller: tabController,
children: List<Widget>.generate(tabCount, (int index) {
return CustomScrollView(
// The bug only occurs when this key is included
key: ValueKey<String>('Page $index'),
slivers: <Widget>[
SliverPersistentHeader(
delegate: MySliverPersistentHeaderDelegate(),
),
],
);
}).toList(),
),
);
}
}
void main() {
testWidgets('Tabbed CustomScrollViews, warp from tab 1 to 3', (WidgetTester tester) async {
await tester.pumpWidget(const MaterialApp(home: MyHomePage()));
// should not crash.
await tester.tap(find.text('Tab 2'));
await tester.pumpAndSettle();
});
}