Improve initial size and placement logic for popups and tooltips on Linux - #189994

// ignore_for_file: invalid_use_of_internal_member
// ignore_for_file: implementation_imports
import 'package:flutter/material.dart';
import 'package:flutter/src/widgets/_window.dart';
import 'package:flutter/src/widgets/_window_positioner.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runWidget(const WindowingApp());
}

final ThemeData _appTheme = ThemeData(
  colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
);

class WindowingApp extends StatefulWidget {
  const WindowingApp({super.key});

  @override
  State<WindowingApp> createState() => _WindowingAppState();
}

class _CallbackPopupDelegate extends PopupWindowControllerDelegate {
  _CallbackPopupDelegate({required this.onDestroyCallback});

  final VoidCallback onDestroyCallback;

  @override
  void onWindowDestroyed() {
    onDestroyCallback();
  }
}

class _WindowingAppState extends State<WindowingApp> {
  final WindowController _windowController = WindowController(
    size: Size(800, 600),
    title: "Tester",
  );
  PopupWindowController? _popupWindowController;

  void _togglePopup(Rect anchorRect) {
    if (_popupWindowController != null) {
      _popupWindowController!.destroy();
      return;
    }

    setState(() {
      _popupWindowController = PopupWindowController(
        parent: _windowController,
        anchorRect: anchorRect,
        positioner: const WindowPositioner(
          parentAnchor: .topRight,
          childAnchor: .topLeft,
          constraintAdjustment: WindowPositionerConstraintAdjustment(
            flipY: true,
            slideX: true,
            slideY: true,
            resizeY: true,
          ),
        ),
        delegate: _CallbackPopupDelegate(
          onDestroyCallback: () {
            setState(() {
              _popupWindowController = null;
            });
          },
        ),
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    return ViewCollection(
      views: [
        Window(
          controller: _windowController,
          child: MyApp(onTogglePopup: _togglePopup),
        ),
        if (_popupWindowController != null)
          PopupWindow(
            controller: _popupWindowController!,
            child: SizedBox(
              width: 400,
              height: 200,
              child: MaterialApp(
                debugShowCheckedModeBanner: false,
                theme: _appTheme,
                home: Material(
                  color: _appTheme.colorScheme.surfaceContainer,
                  child: ListView.builder(
                    shrinkWrap: true,
                    itemCount: 100,
                    itemBuilder: (BuildContext context, int index) {
                      return ListTile(
                        dense: true,
                        title: Text('Item $index'),
                        onTap: () => _popupWindowController?.destroy(),
                      );
                    },
                  ),
                ),
              ),
            ),
          ),
      ],
    );
  }
}

class MyApp extends StatelessWidget {
  const MyApp({super.key, required this.onTogglePopup});

  final ValueChanged<Rect> onTogglePopup;

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: _appTheme,
      home: MyHomePage(
        title: 'Flutter Demo Home Page',
        onTogglePopup: onTogglePopup,
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({
    super.key,
    required this.title,
    required this.onTogglePopup,
  });

  final String title;
  final ValueChanged<Rect> onTogglePopup;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final GlobalKey _fabKey = GlobalKey();

  void _onPressed() {
    final Rect? anchorRect = _getAnchorRect();
    if (anchorRect == null) {
      return;
    }
    widget.onTogglePopup(anchorRect);
  }

  Rect? _getAnchorRect() {
    final RenderBox? renderBox =
        _fabKey.currentContext?.findRenderObject() as RenderBox?;
    if (renderBox == null) {
      return null;
    }
    final Rect rect = renderBox.localToGlobal(Offset.zero) & renderBox.size;
    return rect;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: .center,
          children: [const Text('Click the button to show the popup')],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        key: _fabKey,
        onPressed: _onPressed,
        tooltip: 'Show Popup',
        child: const Icon(Icons.add),
      ),
    );
  }
}

          PopupWindow(
            controller: _popupWindowController!,
            child: Container(
              child: MaterialApp(
                debugShowCheckedModeBanner: false,
                theme: _appTheme,
                home: Material(
                  color: _appTheme.colorScheme.surfaceContainer,
                  child: ListView.builder(
                    shrinkWrap: true,
                    itemCount: 100,
                    itemBuilder: (BuildContext context, int index) {
                      return ListTile(
                        dense: true,
                        title: Text('Item $index'),
                        onTap: () => _popupWindowController?.destroy(),
                      );
                    },
                  ),
                ),
              ),
            ),
          )