flutter/packages/unit/test/widget/snap_scrolling_test.dart

118 lines
2.8 KiB
Dart

// Copyright 2015 The Chromium 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 'dart:async';
import 'package:flutter/widgets.dart';
import 'package:test/test.dart';
import 'widget_tester.dart';
const double itemExtent = 200.0;
ScrollDirection scrollDirection = ScrollDirection.vertical;
GlobalKey scrollableListKey;
Widget buildItem(BuildContext context, int item) {
return new Container(
key: new ValueKey<int>(item),
width: itemExtent,
height: itemExtent,
child: new Text(item.toString())
);
}
double snapOffsetCallback(double offset) {
return (offset / itemExtent).floor() * itemExtent;
}
Widget buildFrame() {
scrollableListKey = new GlobalKey();
return new Center(
child: new Container(
height: itemExtent * 2.0,
child: new ScrollableList<int>(
key: scrollableListKey,
snapOffsetCallback: snapOffsetCallback,
scrollDirection: scrollDirection,
items: <int>[0, 1, 2, 3, 4, 5, 7, 8, 9],
itemBuilder: buildItem,
itemExtent: itemExtent
)
)
);
}
ScrollableState get scrollableState => scrollableListKey.currentState;
double get scrollOffset => scrollableState.scrollOffset;
void set scrollOffset(double value) {
scrollableState.scrollTo(value);
}
Future fling(double velocity) {
Offset velocityOffset = scrollDirection == ScrollDirection.vertical
? new Offset(0.0, velocity)
: new Offset(velocity, 0.0);
return scrollableState.fling(velocityOffset);
}
void main() {
test('ScrollableList snap scrolling, fling(-800)', () {
testWidgets((WidgetTester tester) {
tester.pumpWidget(buildFrame());
scrollOffset = 0.0;
tester.pump();
expect(scrollOffset, 0.0);
Duration dt = const Duration(seconds: 2);
fling(-800.0);
tester.pump(); // Start the scheduler at 0.0
tester.pump(dt);
expect(scrollOffset, closeTo(200.0, 1.0));
scrollOffset = 0.0;
tester.pump();
expect(scrollOffset, 0.0);
fling(-2000.0);
tester.pump();
tester.pump(dt);
expect(scrollOffset, closeTo(400.0, 1.0));
scrollOffset = 400.0;
tester.pump();
expect(scrollOffset, 400.0);
fling(800.0);
tester.pump();
tester.pump(dt);
expect(scrollOffset, closeTo(0.0, 1.0));
scrollOffset = 800.0;
tester.pump();
expect(scrollOffset, 800.0);
fling(2000.0);
tester.pump();
tester.pump(dt);
expect(scrollOffset, closeTo(200.0, 1.0));
scrollOffset = 800.0;
tester.pump();
expect(scrollOffset, 800.0);
bool completed = false;
fling(2000.0).then((_) {
completed = true;
expect(scrollOffset, closeTo(200.0, 1.0));
});
tester.pump();
tester.pump(dt);
expect(completed, true);
});
});
}