| // 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_test/flutter_test.dart'; |
| import 'package:flutter/widgets.dart'; |
| |
| // Assuming that the test container is 800x600. The height of the |
| // viewport's contents is 650.0, the top and bottom text children |
| // are 100 pixels high and top/left edge of both widgets are visible. |
| // The top of the bottom widget is at 550 (the top of the top widget |
| // is at 0). The top of the bottom widget is 500 when it has been |
| // scrolled completely into view. |
| Widget buildFrame(ScrollPhysics physics, { ScrollController scrollController }) { |
| return SingleChildScrollView( |
| key: UniqueKey(), |
| physics: physics, |
| controller: scrollController, |
| child: SizedBox( |
| height: 650.0, |
| child: Column( |
| crossAxisAlignment: CrossAxisAlignment.start, |
| textDirection: TextDirection.ltr, |
| children: <Widget>[ |
| const SizedBox(height: 100.0, child: Text('top', textDirection: TextDirection.ltr)), |
| Expanded(child: Container()), |
| const SizedBox(height: 100.0, child: Text('bottom', textDirection: TextDirection.ltr)), |
| ], |
| ), |
| ), |
| ); |
| } |
| |
| void main() { |
| testWidgets('ClampingScrollPhysics', (WidgetTester tester) async { |
| |
| // Scroll the target text widget by offset and then return its origin |
| // in global coordinates. |
| Future<Offset> locationAfterScroll(String target, Offset offset) async { |
| await tester.dragFrom(tester.getTopLeft(find.text(target)), offset); |
| await tester.pump(); |
| final RenderBox textBox = tester.renderObject(find.text(target)); |
| final Offset widgetOrigin = textBox.localToGlobal(Offset.zero); |
| await tester.pump(const Duration(seconds: 1)); // Allow overscroll to settle |
| return Future<Offset>.value(widgetOrigin); |
| } |
| |
| await tester.pumpWidget(buildFrame(const BouncingScrollPhysics())); |
| Offset origin = await locationAfterScroll('top', const Offset(0.0, 400.0)); |
| expect(origin.dy, greaterThan(0.0)); |
| origin = await locationAfterScroll('bottom', const Offset(0.0, -400.0)); |
| expect(origin.dy, lessThan(500.0)); |
| |
| |
| await tester.pumpWidget(buildFrame(const ClampingScrollPhysics())); |
| origin = await locationAfterScroll('top', const Offset(0.0, 400.0)); |
| expect(origin.dy, equals(0.0)); |
| origin = await locationAfterScroll('bottom', const Offset(0.0, -400.0)); |
| expect(origin.dy, equals(500.0)); |
| }); |
| |
| testWidgets('ClampingScrollPhysics affects ScrollPosition', (WidgetTester tester) async { |
| |
| // BouncingScrollPhysics |
| |
| await tester.pumpWidget(buildFrame(const BouncingScrollPhysics())); |
| ScrollableState scrollable = tester.state(find.byType(Scrollable)); |
| |
| await tester.dragFrom(tester.getTopLeft(find.text('top')), const Offset(0.0, 400.0)); |
| await tester.pump(); |
| expect(scrollable.position.pixels, lessThan(0.0)); |
| await tester.pump(const Duration(seconds: 1)); // Allow overscroll to settle |
| |
| await tester.dragFrom(tester.getTopLeft(find.text('bottom')), const Offset(0.0, -400.0)); |
| await tester.pump(); |
| expect(scrollable.position.pixels, greaterThan(0.0)); |
| await tester.pump(const Duration(seconds: 1)); // Allow overscroll to settle |
| |
| // ClampingScrollPhysics |
| |
| await tester.pumpWidget(buildFrame(const ClampingScrollPhysics())); |
| scrollable = scrollable = tester.state(find.byType(Scrollable)); |
| |
| await tester.dragFrom(tester.getTopLeft(find.text('top')), const Offset(0.0, 400.0)); |
| await tester.pump(); |
| expect(scrollable.position.pixels, equals(0.0)); |
| await tester.pump(const Duration(seconds: 1)); // Allow overscroll to settle |
| |
| await tester.dragFrom(tester.getTopLeft(find.text('bottom')), const Offset(0.0, -400.0)); |
| await tester.pump(); |
| expect(scrollable.position.pixels, equals(50.0)); |
| }); |
| |
| testWidgets('ClampingScrollPhysics handles out of bounds ScrollPosition', (WidgetTester tester) async { |
| Future<void> testOutOfBounds(ScrollPhysics physics, double initialOffset, double expectedOffset) async { |
| final ScrollController scrollController = ScrollController(initialScrollOffset: initialOffset); |
| await tester.pumpWidget(buildFrame(physics, scrollController: scrollController)); |
| final ScrollableState scrollable = tester.state(find.byType(Scrollable)); |
| |
| expect(scrollable.position.pixels, equals(initialOffset)); |
| await tester.pump(const Duration(seconds: 1)); // Allow overscroll to settle |
| expect(scrollable.position.pixels, equals(expectedOffset)); |
| } |
| |
| await testOutOfBounds(const ClampingScrollPhysics(), -400.0, 0.0); |
| await testOutOfBounds(const ClampingScrollPhysics(), 800.0, 50.0); |
| }); |
| } |