Navigator.pushで変更アプリケーションバーのデフォルトのarrow_backのアイコン

Question

新しいページのアプリケーションバー有数のアイコンは、arrow_back私は暗黙のうちにすべてのページarrow_forwardするアイコンを変更したい です。

方向性はRTL

可能ですか？

Answer 1

UPDATE

フラッターは現在のアイコンのための方向性を処理します。私は、ソースコードを読んで

---

、方向性は、戻るボタンのために、今とはみなされません。

だから私は、SRC

appBar: new AppBar(
     leading: getAppBarLeading(context), 

自分BackButton2とgetAppBarLeading機能を作った：

// Copyright 2017 The Chromium 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/material.dart'; 

const double _kLeadingWidth = 
    kToolbarHeight; // So the leading button is square. 

/// 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 BackButtonIcon2 extends StatelessWidget { 
    /// Creates an icon that shows the appropriate "back" image for 
    /// the current platform (as obtained from the [Theme]). 
    const BackButtonIcon2({Key key}) : super(key: key); 

    /// Returns the appropriate "back" icon for the given `platform`. 
    static IconData _getIconData(
     TargetPlatform platform, TextDirection direction) { 
    switch (platform) { 
     case TargetPlatform.android: 
     case TargetPlatform.fuchsia: 
     return (direction == TextDirection.rtl) 
      ? Icons.arrow_forward 
      : Icons.arrow_back; 
     case TargetPlatform.iOS: 
     return (direction == TextDirection.rtl) 
      ? Icons.arrow_forward_ios 
      : Icons.arrow_back_ios; 
    } 
    assert(false); 
    return null; 
    } 

    @override 
    Widget build(BuildContext context) => new Icon(_getIconData(
     Theme.of(context).platform, 
     Directionality.of(context), 
    )); 
} 

/// 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. 
/// 
/// 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 BackButton2 extends StatelessWidget { 
    /// Creates an [IconButton] with the appropriate "back" icon for the current 
    /// target platform. 
    const BackButton2({Key key, this.color}) : super(key: key); 

    /// 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; 

    @override 
    Widget build(BuildContext context) { 
    return new IconButton(
     icon: const BackButtonIcon2(), 
     color: color, 
     tooltip: MaterialLocalizations.of(context).backButtonTooltip, 
     onPressed:() { 
      Navigator.of(context).maybePop(); 
     }); 
    } 
} 

/// 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 CloseButton2 extends StatelessWidget { 
    /// Creates a Material Design close button. 
    const CloseButton2({Key key}) : super(key: key); 

    @override 
    Widget build(BuildContext context) { 
    return new IconButton(
     icon: const Icon(Icons.close), 
     tooltip: MaterialLocalizations.of(context).closeButtonTooltip, 
     onPressed:() { 
     Navigator.of(context).maybePop(); 
     }, 
    ); 
    } 
} 

Widget getAppBarLeading(BuildContext context) { 
    final ModalRoute<dynamic> parentRoute = ModalRoute.of(context); 
    final bool canPop = parentRoute?.canPop ?? false; 
    final bool useCloseButton = 
     parentRoute is MaterialPageRoute<dynamic> && parentRoute.fullscreenDialog; 
    Widget leading = canPop 
     ? (useCloseButton ? const CloseButton2() : const BackButton2()) 
     : null; 
    if (leading != null) { 
    leading = new ConstrainedBox(
     constraints: const BoxConstraints.tightFor(width: _kLeadingWidth), 
     child: leading, 
    ); 
    } 
    return leading; 
}