examples/api/lib/widgets/windows/window_manager.0.dart

// 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.

// TODO(mattkae): remove invalid_use_of_internal_member ignore comment when this API is stable.
// See: https://github.com/flutter/flutter/issues/177586
// ignore_for_file: invalid_use_of_internal_member
// ignore_for_file: implementation_imports
import 'package:flutter/widgets.dart';
import 'package:flutter/src/widgets/_window.dart';

void main() {
  try {
    WidgetsFlutterBinding.ensureInitialized();
    final RegularWindowController controller = RegularWindowController(
      preferredSize: const Size(800, 600),
    );
    runWidget(
      WindowManager(
        child: RegularWindow(controller: controller, child: const MainWindow()),
      ),
    );
  } on UnsupportedError catch (e) {
    // TODO(mattkae): Remove this catch block when windowing is supported in tests.
    // For now, we need to catch the error so that the API smoke tests pass.
    runApp(
      WidgetsApp(
        color: const Color(0xFFFFFFFF),
        builder: (BuildContext context, Widget? child) {
          return Center(
            child: Text(
              e.message ?? 'Unsupported',
              textDirection: TextDirection.ltr,
            ),
          );
        },
      ),
    );
  }
}

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

  @override
  State<StatefulWidget> createState() => MainWindowState();
}

class MainWindowState extends State<MainWindow> {
  WindowEntry? entry;

  void _openDialog(BuildContext context) {
    final WindowRegistry? registry = WindowRegistry.maybeOf(context);
    assert(registry != null);
    entry = WindowEntry(
      controller: DialogWindowController(
        parent: WindowScope.of(context),
        preferredSize: const Size(400, 300),
        delegate: _DialogWindowControllerDelegate(
          mainWindow: this,
          registry: registry!,
        ),
      ),
      builder: (BuildContext context) {
        return const SizedBox.shrink();
      },
    );
    registry.register(entry!);
  }

  void closeDialog(WindowRegistry registry) {
    if (entry != null) {
      registry.unregister(entry!);
      entry = null;
    }
  }

  @override
  Widget build(BuildContext context) {
    return WidgetsApp(
      color: const Color(0xFFFFFFFF),
      builder: (BuildContext context, Widget? child) {
        return Center(
          child: GestureDetector(
            onTap: () => _openDialog(context),
            child: const Text(
              'Open a dialog',
              textDirection: TextDirection.ltr,
            ),
          ),
        );
      },
    );
  }
}

class _DialogWindowControllerDelegate extends DialogWindowControllerDelegate {
  _DialogWindowControllerDelegate({
    required this.mainWindow,
    required this.registry,
  });

  final MainWindowState mainWindow;
  final WindowRegistry registry;

  @override
  void onWindowDestroyed() {
    super.onWindowDestroyed();
    mainWindow.closeDialog(registry);
  }
}