Repro Customer Issue

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(const BugExample());
}

class BugExample extends StatelessWidget {
  const BugExample();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.grey,
        body: KeyboardAwareDraggableScrollableSheet(
          builder: (_, controller) => SingleChildScrollView(
              controller: controller,
              child: Container(
          color: Colors.white,
          child: Column(
            children: [
              TextField(),
              Text('one'),
              Text('two'),
              Text('three'),
              Container(width: 50, height: 50, color: Colors.red),
              Text('four'),
              Text('five'),
              Text('six'),
              Container(width: 50, height: 50, color: Colors.green),
              Text('seven'),
              Text('eight'),
              Text('nine'),
              Container(width: 50, height: 50, color: Colors.blue),
              Text('ten'),
              Text('eleven'),
              Text('twelve'),
            ],
          ),
        ),
            ),
        ),
      ),
    );
  }
}

class KeyboardAwareDraggableScrollableSheet extends StatefulWidget {
  const KeyboardAwareDraggableScrollableSheet({
    super.key,
    required this.builder,
  });
  final ScrollableWidgetBuilder builder;

  @override
  State<KeyboardAwareDraggableScrollableSheet> createState() =>
      _KeyboardAwareDraggableScrollableSheetState();
}

class _KeyboardAwareDraggableScrollableSheetState
    extends State<KeyboardAwareDraggableScrollableSheet> {
  var _virtualKeyboardUp = false;
  var _previousPosition = 1.0;

  late DraggableScrollableController _draggableScrollableController;
  late ScrollController _draggableSheetScrollController;

  @override
  void initState() {
    super.initState();
    _draggableScrollableController = DraggableScrollableController();
  }

  void _updateLayoutForVirtualKeyboard(
    BuildContext context,
    BoxConstraints constraints,
  ) {
    final bottom = MediaQuery.of(context).viewInsets.bottom;
    final keyboardCurrentlyUp = bottom > 0;
    if (_virtualKeyboardUp != keyboardCurrentlyUp) {
      _virtualKeyboardUp = keyboardCurrentlyUp;
      WidgetsBinding.instance.addPostFrameCallback((_) {
        late double targetSize;
        final sheetSize = _draggableScrollableController.isAttached
            ? _draggableScrollableController.size
            : 0.5;
        final scrollPosition = _draggableScrollableController.isAttached
            ? _draggableSheetScrollController.position.pixels
            : 0;
        if (_virtualKeyboardUp) {
          targetSize = 1.0;
          _previousPosition = sheetSize;
        } else if (scrollPosition == 0) {
          targetSize = _previousPosition;
        } else {
          return;
        }
        if (_draggableScrollableController.isAttached) {
          _draggableScrollableController.animateTo(
            targetSize,
            duration: const Duration(milliseconds: 200),
            curve: Curves.easeOut,
          );
        }
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        _updateLayoutForVirtualKeyboard(context, constraints);
        return DraggableScrollableSheet(
          controller: _draggableScrollableController,
          builder: (context, controller) {
            _draggableSheetScrollController = controller;
            final child = widget.builder(context, controller);
            return Padding(
                    padding: EdgeInsetsDirectional.only(
                      top: MediaQuery.of(context).viewInsets.top,
                      bottom: MediaQuery.of(context).viewInsets.bottom,
                    ),
                    child: child,
                  );
          },
        );
      },
    );
  }
}

main_test.dart

// This is a basic Flutter widget test.
//
// To perform an interaction with a widget in your test, use the WidgetTester
// utility in the flutter_test package. For example, you can send tap and scroll
// gestures. You can also use WidgetTester to find child widgets in the widget
// tree, read text, and verify that the values of widget properties are correct.

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:triage_october/main.dart';

void main() {
  final keyboardHeight = ValueNotifier<double>(0);

  Future<void> simulateKeyboardUp(WidgetTester tester) async {
    keyboardHeight.value = 150;
    await tester.pumpAndSettle();
  }

  Future<void> simulateKeyboardDown(WidgetTester tester) async {
    await tester.pumpAndSettle();
  }

  testWidgets('Repro', (WidgetTester tester) async {
    tester.view
      ..physicalSize = const Size(300, 400)
      ..devicePixelRatio = 1.0;

    final app = MaterialApp(
      home: Scaffold(
        body: VirtualKeyboardSimulator(
          keyboardHeight: keyboardHeight,
          child: Container(
            alignment: Alignment.bottomRight,
            child: Stack(
              children: [
                Container(color: Colors.grey),
                KeyboardAwareDraggableScrollableSheet(
                  builder: (_, controller) => SingleChildScrollView(
                    controller: controller,
                    child: Container(
                      color: Colors.white,
                      child: Column(
                        children: [
                          const Text('one'),
                          const Text('two'),
                          const Text('three'),
                          Container(width: 50, height: 50, color: Colors.red),
                          const Text('four'),
                          const Text('five'),
                          const Text('six'),
                          Container(width: 50, height: 50, color: Colors.green),
                          const Text('seven'),
                          const Text('eight'),
                          const Text('nine'),
                          Container(width: 50, height: 50, color: Colors.blue),
                          const Text('ten'),
                          const Text('eleven'),
                          const Text('twelve'),
                        ],
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
    await tester.pumpWidget(app);

    await expectLater(
      find.byType(MaterialApp),
      matchesGoldenFile('1_bottom_sheet_default_state.png'),
    );

    await simulateKeyboardUp(tester);

    await expectLater(
      find.byType(MaterialApp),
      matchesGoldenFile(
        '2_bottom_sheet_with_keyboard_up.png',
      ),
    );

    // Scroll down to reveal the element 'seven'.
    await tester.scrollUntilVisible(find.text('seven'), 5.0);
    await tester.pumpAndSettle();

    await expectLater(
      find.byType(MaterialApp),
      matchesGoldenFile(
        '3_bottom_sheet_scrolled_down_with_keyboard_up.png',
      ),
    );

    await simulateKeyboardDown(tester);

    // Because the user scrolled down, the sheet will stay up when the
    // keyboard goes down.
    await expectLater(
      find.byType(MaterialApp),
      matchesGoldenFile('4_bottom_sheet_scrolled_down.png'),
    );
  });
}

class VirtualKeyboardSimulator extends StatelessWidget {
  const VirtualKeyboardSimulator({
    super.key,
    required this.keyboardHeight,
    required this.child,
  });

  final Widget child;
  final ValueNotifier<double> keyboardHeight;

  Widget _keyboard() {
    final rows = ['qwertyuiop', 'asdfghjkl', 'zxcvbnm'];
    return Column(
      children: [
        const Text('Virtual Keyboard'),
        for (String row in rows)
          Center(
            child: Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                for (var j = 0; j < row.length; j++)
                  Padding(
                    padding: const EdgeInsets.symmetric(
                      horizontal: 2.0,
                      vertical: 3.0,
                    ),
                    child: Container(
                      width: 21,
                      height: 21,
                      color: Colors.grey[200],
                      child: Center(
                        child: Text(
                          row.substring(j, j + 1),
                        ),
                      ),
                    ),
                  ),
              ],
            ),
          
        ),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    return ValueListenableBuilder<double>(
        valueListenable: keyboardHeight,
        builder: (context, value, _) => MediaQuery(
          data: MediaQueryData(
            viewInsets: EdgeInsets.only(bottom: value),
          ),
          child: Stack(
            children: [
              child,
              Align(
                alignment: Alignment.bottomCenter,
                child: Container(
                  color: Colors.grey[100],
                  height: value,
                  child: ClipRect(
                    child: OverflowBox(
                      maxHeight: double.infinity,
                      maxWidth: double.infinity,
                      alignment: Alignment.topCenter,
                      child: _keyboard(),
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      );
  }
}