| // 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. |
| |
| import 'package:flutter/widgets.dart'; |
| |
| import 'debug.dart'; |
| import 'icon_button.dart'; |
| import 'icons.dart'; |
| import 'material_localizations.dart'; |
| import 'theme.dart'; |
| |
| /// A "back" icon that's appropriate for the current [TargetPlatform]. |
| /// |
| /// The current platform is determined by querying for the ambient [Theme]. |
| /// |
| /// See also: |
| /// |
| /// * [BackButton], an [IconButton] with a [BackButtonIcon] that calls |
| /// [Navigator.maybePop] to return to the previous route. |
| /// * [IconButton], which is a more general widget for creating buttons |
| /// with icons. |
| /// * [Icon], a Material Design icon. |
| /// * [ThemeData.platform], which specifies the current platform. |
| class BackButtonIcon extends StatelessWidget { |
| /// Creates an icon that shows the appropriate "back" image for |
| /// the current platform (as obtained from the [Theme]). |
| const BackButtonIcon({ super.key }); |
| |
| /// Returns the appropriate "back" icon for the given `platform`. |
| static IconData _getIconData(TargetPlatform platform) { |
| switch (platform) { |
| case TargetPlatform.android: |
| case TargetPlatform.fuchsia: |
| case TargetPlatform.linux: |
| case TargetPlatform.windows: |
| return Icons.arrow_back; |
| case TargetPlatform.iOS: |
| case TargetPlatform.macOS: |
| return Icons.arrow_back_ios; |
| } |
| } |
| |
| @override |
| Widget build(BuildContext context) => Icon(_getIconData(Theme.of(context).platform)); |
| } |
| |
| /// A Material Design back button. |
| /// |
| /// A [BackButton] is an [IconButton] with a "back" icon appropriate for the |
| /// current [TargetPlatform]. When pressed, the back button calls |
| /// [Navigator.maybePop] to return to the previous route unless a custom |
| /// [onPressed] callback is provided. |
| /// |
| /// When deciding to display a [BackButton], consider using |
| /// `ModalRoute.of(context)?.canPop` to check whether the current route can be |
| /// popped. If that value is false (e.g., because the current route is the |
| /// initial route), the [BackButton] will not have any effect when pressed, |
| /// which could frustrate the user. |
| /// |
| /// Requires one of its ancestors to be a [Material] widget. |
| /// |
| /// See also: |
| /// |
| /// * [AppBar], which automatically uses a [BackButton] in its |
| /// [AppBar.leading] slot when the [Scaffold] has no [Drawer] and the |
| /// current [Route] is not the [Navigator]'s first route. |
| /// * [BackButtonIcon], which is useful if you need to create a back button |
| /// that responds differently to being pressed. |
| /// * [IconButton], which is a more general widget for creating buttons with |
| /// icons. |
| /// * [CloseButton], an alternative which may be more appropriate for leaf |
| /// node pages in the navigation tree. |
| class BackButton extends StatelessWidget { |
| /// Creates an [IconButton] with the appropriate "back" icon for the current |
| /// target platform. |
| const BackButton({ super.key, this.color, this.onPressed }); |
| |
| /// The color to use for the icon. |
| /// |
| /// Defaults to the [IconThemeData.color] specified in the ambient [IconTheme], |
| /// which usually matches the ambient [Theme]'s [ThemeData.iconTheme]. |
| final Color? color; |
| |
| /// An override callback to perform instead of the default behavior which is |
| /// to pop the [Navigator]. |
| /// |
| /// It can, for instance, be used to pop the platform's navigation stack |
| /// via [SystemNavigator] instead of Flutter's [Navigator] in add-to-app |
| /// situations. |
| /// |
| /// Defaults to null. |
| final VoidCallback? onPressed; |
| |
| @override |
| Widget build(BuildContext context) { |
| assert(debugCheckHasMaterialLocalizations(context)); |
| return IconButton( |
| icon: const BackButtonIcon(), |
| color: color, |
| tooltip: MaterialLocalizations.of(context).backButtonTooltip, |
| onPressed: () { |
| if (onPressed != null) { |
| onPressed!(); |
| } else { |
| Navigator.maybePop(context); |
| } |
| }, |
| ); |
| } |
| } |
| |
| /// A Material Design close button. |
| /// |
| /// A [CloseButton] is an [IconButton] with a "close" icon. When pressed, the |
| /// close button calls [Navigator.maybePop] to return to the previous route. |
| /// |
| /// Use a [CloseButton] instead of a [BackButton] on fullscreen dialogs or |
| /// pages that may solicit additional actions to close. |
| /// |
| /// See also: |
| /// |
| /// * [AppBar], which automatically uses a [CloseButton] in its |
| /// [AppBar.leading] slot when appropriate. |
| /// * [BackButton], which is more appropriate for middle nodes in the |
| /// navigation tree or where pages can be popped instantaneously with |
| /// no user data consequence. |
| /// * [IconButton], to create other Material Design icon buttons. |
| class CloseButton extends StatelessWidget { |
| /// Creates a Material Design close button. |
| const CloseButton({ super.key, this.color, this.onPressed }); |
| |
| /// The color to use for the icon. |
| /// |
| /// Defaults to the [IconThemeData.color] specified in the ambient [IconTheme], |
| /// which usually matches the ambient [Theme]'s [ThemeData.iconTheme]. |
| final Color? color; |
| |
| /// An override callback to perform instead of the default behavior which is |
| /// to pop the [Navigator]. |
| /// |
| /// It can, for instance, be used to pop the platform's navigation stack |
| /// via [SystemNavigator] instead of Flutter's [Navigator] in add-to-app |
| /// situations. |
| /// |
| /// Defaults to null. |
| final VoidCallback? onPressed; |
| |
| @override |
| Widget build(BuildContext context) { |
| assert(debugCheckHasMaterialLocalizations(context)); |
| return IconButton( |
| icon: const Icon(Icons.close), |
| color: color, |
| tooltip: MaterialLocalizations.of(context).closeButtonTooltip, |
| onPressed: () { |
| if (onPressed != null) { |
| onPressed!(); |
| } else { |
| Navigator.maybePop(context); |
| } |
| }, |
| ); |
| } |
| } |