scrollable_of_test.dart 2.58 KB
// 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/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:sheet/sheet.dart';

class ScrollPositionListener extends StatefulWidget {
  const ScrollPositionListener(
      {super.key, required this.child, required this.log});

  final Widget child;
  final ValueChanged<String> log;

  @override
  State<ScrollPositionListener> createState() => _ScrollPositionListenerState();
}

class _ScrollPositionListenerState extends State<ScrollPositionListener> {
  ScrollPosition? _position;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _position?.removeListener(listener);
    _position = SheetScrollable.of(context)?.position;
    _position?.addListener(listener);
    widget.log('didChangeDependencies ${_position?.pixels.toStringAsFixed(1)}');
  }

  @override
  void dispose() {
    _position?.removeListener(listener);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) => widget.child;

  void listener() {
    widget.log('listener ${_position?.pixels.toStringAsFixed(1)}');
  }
}

void main() {
  testWidgets(
      'SheetScrollable.of() dependent rebuilds when SheetScrollable position changes',
      (WidgetTester tester) async {
    late String logValue;
    final SheetController controller = SheetController();

    // Changing the SingleChildScrollView's physics causes the
    // ScrollController's ScrollPosition to be rebuilt.

    Widget buildFrame(SheetPhysics? physics) {
      return MaterialApp(
        home: Sheet(
          controller: controller,
          physics: physics,
          child: ScrollPositionListener(
            log: (String s) {
              logValue = s;
            },
            child: const SizedBox(height: 400.0),
          ),
        ),
      );
    }

    await tester.pumpWidget(buildFrame(null));
    expect(logValue, 'didChangeDependencies 0.0');

    controller.jumpTo(100.0);
    expect(logValue, 'listener 100.0');

    await tester.pumpWidget(buildFrame(const AlwaysDraggableSheetPhysics()));
    expect(logValue, 'didChangeDependencies 100.0');

    controller.jumpTo(200.0);
    expect(logValue, 'listener 200.0');

    controller.jumpTo(300.0);
    expect(logValue, 'listener 300.0');

    await tester
        .pumpWidget(buildFrame(const SnapSheetPhysics(stops: <double>[0, 1])));
    expect(logValue, 'didChangeDependencies 300.0');

    controller.jumpTo(400.0);
    expect(logValue, 'listener 400.0');
  });
}