void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        dialogTheme: const DialogTheme(
          barrierColor: Colors.green,
        ),
      ),
      home: const DialogExample(),
    );
  }
}

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

  @override
  State<DialogExample> createState() => _DialogExampleState();
}

class _DialogExampleState extends State<DialogExample> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            FilledButton(
              onPressed: () {
                showDialog(
                  context: context,
                  builder: (context) {
                    return const Dialog(
                      child: Text("Dialog"),
                    );
                  },
                );
              },
              child: const Text("Show Dialog"),
            ),
            FilledButton(
              onPressed: () {
                showDialog(
                  context: context,
                  builder: (context) {
                    return const AlertDialog(
                      content: Text("Alert"),
                    );
                  },
                );
              },
              child: const Text("Show AlertDialog"),
            ),
          ],
        ),
      ),
    );
  }
}