我不知道如何将appBar的自动后退按钮更改为不同的颜色。它在脚手架下，我试图研究它，但我无法理解它。
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.white,
title: Image.asset(
'images/.jpg',
fit: BoxFit.fill,
),
centerTitle: true,
),
当前回答
你可以像下面这样使用iconTheme:
iconTheme: IconThemeData(
color: Colors.black, // <= You can change your color here.
),
其他回答
更改CupertinoPageScaffold的主色调
Theme(
data: Theme.of(context).copyWith(
cupertinoOverrideTheme: CupertinoThemeData(
scaffoldBackgroundColor: Colors.white70,
primaryColor: Styles.green21D877, // HERE COLOR OF LEADING
),
),
child: CupertinoPageScaffold(
navigationBar: CupertinoNavigationBar(
brightness: Brightness.light,
backgroundColor: Colors.white,
middle: Text('Cupertino App Bar'),
),
child: Container(
child: Center(
child: CupertinoActivityIndicator(),
),
),
),
)
你也可以通过'leading'来覆盖默认的后退箭头:
leading: new IconButton(
icon: new Icon(Icons.arrow_back, color: Colors.orange),
onPressed: () => Navigator.of(context).pop(),
),
AppBar小部件所做的就是在没有设置的情况下提供一个默认的“leading”小部件。
要自定义引导图标，您可能需要模仿AppBar小部件的功能，该小部件根据当前上下文正确地处理显示后退按钮、抽屉图标或关闭图标。下面是一个替换默认图标的例子。
import 'package:flutter/material.dart';
class TopBar extends StatelessWidget with PreferredSizeWidget {
static const double _topBarHeight = 60;
@override
Widget build(BuildContext context) {
return AppBar(
toolbarHeight: _topBarHeight,
title: Text('Title'),
automaticallyImplyLeading: false,
leading: _buildLeadingWidget(context),
);
}
@override
Size get preferredSize => Size.fromHeight(_topBarHeight);
Widget _buildLeadingWidget(BuildContext context) {
final ScaffoldState scaffold = Scaffold.of(context);
final ModalRoute<dynamic> parentRoute = ModalRoute.of(context);
final bool canPop = ModalRoute.of(context)?.canPop ?? false;
final bool hasDrawer = scaffold?.hasDrawer ?? false;
final bool useCloseButton = parentRoute is PageRoute<dynamic> && parentRoute.fullscreenDialog;
Widget leading;
if (hasDrawer) {
leading = IconButton(
icon: const Icon(Icons.menu_rounded),
onPressed: Scaffold.of(context).openDrawer,
tooltip: MaterialLocalizations.of(context).openAppDrawerTooltip,
);
} else {
if (canPop) {
if (useCloseButton) {
leading = IconButton(
color: Theme.of(context).colorScheme.onBackground,
icon: Icon(Icons.close_rounded),
onPressed: () => Navigator.of(context).maybePop());
} else {
leading = IconButton(
padding: EdgeInsets.all(0),
iconSize: 38,
icon: Icon(Icons.chevron_left_rounded),
onPressed: Navigator.of(context).pop);
}
}
}
return leading;
}
}
这个类使用PreferredSizeWidget作为一个mixin，因此您可以使用它来替换脚手架中现有的AppBar小部件。请注意_buildLeadingWidget方法，它只在必要时显示后退按钮，如果有抽屉，则显示菜单按钮，如果显示全屏对话框，则显示关闭按钮。
在AppBar中，添加前导参数并分配BackButton小部件。然后将颜色参数添加到BackButton，如下所示:
AppBar(
leading: const BackButton(
color: Colors.black, // Change the color here
),
centerTitle: true,
)
你可以像下面这样使用iconTheme:
iconTheme: IconThemeData(
color: Colors.black, // <= You can change your color here.
),
