showOkCancelAdaptiveDialog

main.dart

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

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Dialog Demo',
      theme: ThemeData(
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: const OKCancelAdaptiveDialogCatalogScreen(),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('ShowOKCancelAdaptiveDialog Demo'),
      ),
      body: ListView(
        padding: const EdgeInsets.all(8),
        children: <Widget>[
          ElevatedButton(
            onPressed: () async {
              await showOkCancelAdaptiveDialog(
                context: context,
                title: 'アーカイブしますか？',
                message: 'あとから元に戻すことができます',
              );
            },
            child: const Text('シンプルな確認'),
          ),
        ],
      ),
    );
  }
}

Future<OkCancelResult> showOkCancelAdaptiveDialog({
  required BuildContext context,
  String? title,
  String? message,
  String okLabel = 'OK',
  String cancelLabel = 'キャンセル',
  OkCancelAlertDefaultType? defaultType,
  bool isDestructiveAction = false,
  bool barrierDismissible = true,
}) async {
  const okResult = OkCancelResult.ok;
  const cancelResult = OkCancelResult.cancel;

  final result = await showAdaptiveDialog<OkCancelResult>(
    context: context,
    barrierDismissible: barrierDismissible,
    builder: (BuildContext context) => AlertDialog.adaptive(
      title: title != null ? Text(title) : null,
      content: message != null ? Text(message) : null,
      actions: <Widget>[
        _AdaptiveAction(
          context: context,
          onPressed: () => Navigator.pop(context, cancelResult),
          isDefaultAction: defaultType == OkCancelAlertDefaultType.cancel,
          labelString: cancelLabel,
        ),
        _AdaptiveAction(
          context: context,
          onPressed: () => Navigator.pop(context, okResult),
          isDefaultAction:
              defaultType == null || defaultType == OkCancelAlertDefaultType.ok,
          labelString: okLabel,
          isDestructiveAction: isDestructiveAction,
        ),
      ],
    ),
  );

  return result ?? OkCancelResult.cancel;
}

class _AdaptiveAction extends StatelessWidget {
  const _AdaptiveAction({
    required this.context,
    required this.onPressed,
    required this.isDefaultAction,
    required this.labelString,
    this.isDestructiveAction = false,
  });
  final BuildContext context;
  final VoidCallback onPressed;
  final bool isDefaultAction;
  final String labelString;
  final bool isDestructiveAction;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    switch (theme.platform) {
      case TargetPlatform.android:
      case TargetPlatform.fuchsia:
      case TargetPlatform.linux:
      case TargetPlatform.windows:
        return TextButton(
          onPressed: onPressed,
          child: Text(
            labelString,
            style: isDestructiveAction
                ? TextStyle(color: Theme.of(context).colorScheme.error)
                : null,
          ),
        );
      case TargetPlatform.iOS:
      case TargetPlatform.macOS:
        return CupertinoDialogAction(
          onPressed: onPressed,
          isDefaultAction: isDefaultAction,
          isDestructiveAction: isDestructiveAction,
          child: Text(labelString),
        );
    }
  }
}

enum OkCancelResult {
  ok,
  cancel,
}

enum OkCancelAlertDefaultType {
  ok,
  cancel,
}