WindowCloseGuard

A Flutter package for safe window close handling on desktop with confirmation dialog support.

Features

✅ Intercepts the window close event on Windows, macOS and Linux
✅ Shows a customizable confirmation dialog before closing
✅ Executes async cleanup tasks (saving data, logs, etc.) before the window is destroyed
✅ Handles the close lifecycle correctly on all platforms
✅ Supports dynamic dialog text via dialogConfigBuilder (useful for localization)

Platform support

Platform	Supported
Windows	✅
macOS	✅
Linux	✅
Android	❌
iOS	❌
Web	❌

Installation

Add window_close_guard to your pubspec.yaml:

dependencies:
  window_close_guard: ^1.1.0

Then run:

flutter pub get

Usage

Call WindowCloseGuard.initialize() in didChangeDependencies() of your first stateful widget:

class _MyHomePageState extends State<MyHomePage> {
  @override
  void didChangeDependencies() {
    super.didChangeDependencies();

    WindowCloseGuard.initialize(
      context: context,
      onClose: () async {
        await MyPreferences.save();
        await MyLogger.saveLogs();
      },
      dialogConfig: CloseDialogConfig(
        title: 'Exit',
        content: 'Are you sure you want to exit?',
        confirmText: 'Yes',
        cancelText: 'No',
      ),
    );
  }
}

With localization (dynamic dialog text)

Use dialogConfigBuilder instead of dialogConfig when your dialog text depends on the current locale or any other runtime value. The builder is called at the moment the dialog is shown, so it always reflects the current state:

WindowCloseGuard.initialize(
  context: context,
  onClose: () async {
    await MyPreferences.save();
  },
  dialogConfigBuilder: () => CloseDialogConfig(
    title: AppLocalizations.of(context)!.exit_title,
    content: AppLocalizations.of(context)!.exit_body,
    confirmText: AppLocalizations.of(context)!.yes,
  ),
);

Without a confirmation dialog

If you just want to run cleanup tasks without asking the user for confirmation:

WindowCloseGuard.initialize(
  context: context,
  showDialog: false,
  onClose: () async {
    await MyPreferences.save();
  },
);

Default behavior

Calling initialize() without optional parameters shows a generic confirmation dialog:

WindowCloseGuard.initialize(context: context);

API Reference