【发布时间】：2020-11-15 20:11:25
【问题描述】：
我希望能够使用 DrawerHeader 处的 Switch 更改暗/亮模式。但我遇到了一个错误。
错误：在此消费者小部件上方找不到正确的提供者
这可能是因为您使用了不包含提供程序的BuildContext
你的选择。有几种常见的情况：
- 您尝试读取的提供程序位于不同的路径中。 提供者是“范围的”。因此，如果您在路线内插入提供者，那么 其他路由将无法访问该提供商。
- 您使用了
BuildContext，它是您尝试读取的提供程序的祖先。 确保 Consumer 在您的 MultiProvider/Provider 下。 这通常发生在您创建提供程序并尝试立即读取它时。
anasayfa.dart
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ChangeNotifierProvider<ThemeNotifier>(
create: (_) => ThemeNotifier(),
child: Consumer<ThemeNotifier>(
builder: (context, ThemeNotifier notifier, child) {
return MaterialApp(
title: 'Flutter Theme Provider',
theme: notifier.darkTheme ? dark : light,
home: Anasayfa(),
);
},
),
);
}
}
class Anasayfa extends StatefulWidget {
@override
_AnasayfaState createState() => _AnasayfaState();
}
class _AnasayfaState extends State<Anasayfa> {
int currentPage = 0;
nested() {
return NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return [
SliverAppBar(
toolbarHeight: 40,
expandedHeight: 92.0,
floating: false,
pinned: true,
flexibleSpace: FlexibleSpaceBar(
background: Image.asset(
"assets/images/besmele.jpg",
fit: BoxFit.cover,
),
),
actions: [
IconButton(
icon: Icon(Icons.account_circle),
color: Colors.white,
onPressed: () {},
),
],
)
];
},
body: Container());
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: nested(),
drawer: Drawer(
child: DrawerDosyasi(),
),
bottomNavigationBar: CurvedNavigationBar(
color: Colors.blue,
backgroundColor: Colors.white,
buttonBackgroundColor: Colors.blue,
height: 50,
items: <Widget>[
Icon(
Icons.campaign,
size: 20,
color: Colors.white,
),
Icon(
Icons.supervisor_account,
size: 20,
color: Colors.white,
),
Icon(
Icons.home,
size: 20,
color: Colors.white,
),
Icon(
Icons.video_collection_rounded,
size: 20,
color: Colors.white,
),
Icon(
Icons.menu_book_rounded,
size: 20,
color: Colors.white,
),
],
animationDuration: Duration(
milliseconds: 300,
),
index: 2,
animationCurve: Curves.bounceInOut,
onTap: (index) {
debugPrint("Current index is $index");
},
),
);
}
}
drawerDosyasi.dart
class DrawerDosyasi extends StatefulWidget {
@override
_DrawerDosyasiState createState() => _DrawerDosyasiState();
}
class _DrawerDosyasiState extends State<DrawerDosyasi> {
@override
Widget build(BuildContext context) {
return Container(
child: ListView(
padding: EdgeInsets.zero,
children: <Widget>[
DrawerHeader(
decoration: BoxDecoration(
color: Colors.blue,
),
child: Row(
children: [
Expanded(
flex: 1,
child: Consumer<ThemeNotifier>(
builder: (context, notifier, child) => Switch(
onChanged: (val) {
notifier.toggleTheme();
},
value: notifier.darkTheme,
),
),
),
Expanded(
flex: 3,
child: CircleAvatar(
radius: 60,
backgroundColor: Colors.white,
),
),
Expanded(flex: 1, child: SizedBox.expand()),
],
),
),
ListTile(
leading: Icon(Icons.home),
title: Text('Anasayfa'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.account_circle),
title: Text('Profil'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.campaign),
title: Text('Duyurular'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.account_box),
title: Text('Hocalar'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.library_books),
title: Text('Dergiler'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.video_collection_rounded),
title: Text('Canlı Dersler'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.menu_book_rounded),
title: Text('Kütüphane'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.supervisor_account),
title: Text('Tartışmalar'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.create),
title: Text('Yazı Gönder'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.message_rounded),
title: Text('İletişim'),
tileColor: Colors.white,
),
ListTile(
leading: Icon(Icons.exit_to_app_rounded),
title: Text('Çıkış'),
tileColor: Colors.white,
),
],
),
);
}
}
theme.dart
ThemeData light = ThemeData(
brightness: Brightness.light,
primarySwatch: Colors.blue,
accentColor: Colors.blue,
scaffoldBackgroundColor: Color(0xfff1f1f1));
ThemeData dark = ThemeData(
brightness: Brightness.dark,
primarySwatch: Colors.indigo,
accentColor: Colors.green[700],
);
class ThemeNotifier extends ChangeNotifier {
final String key = "theme";
SharedPreferences _prefs;
bool _darkTheme;
bool get darkTheme => _darkTheme;
ThemeNotifier() {
_darkTheme = true;
_loadFromPrefs();
}
toggleTheme() {
_darkTheme = !_darkTheme;
_saveToPrefs();
notifyListeners();
}
pubspec.yaml
name: mto
description: A new Flutter application.
# The following line prevents the package from being accidentally published to
# pub.dev using `pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev
# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1
environment:
sdk: ">=2.7.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
firebase_database: ^4.3.0
page_transition: ^1.1.7+2
simple_animations: ^2.2.3
curved_navigation_bar: ^0.3.4
provider: ^4.3.2+2
shared_preferences: ^0.5.12+4
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^1.0.0
dev_dependencies:
flutter_test:
sdk: flutter
# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec
# The following section is specific to Flutter.
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
assets:
- assets/images/
# - images/a_dot_ham.jpeg
# An image asset can refer to one or more resolution-specific "variants", see
# https://flutter.dev/assets-and-images/#resolution-aware.
# For details regarding adding assets from package dependencies, see
# https://flutter.dev/assets-and-images/#from-packages
# To add custom fonts to your application, add a fonts section here,
# in this "flutter" section. Each entry in this list should have a
# "family" key with the font family name, and a "fonts" key with a
# list giving the asset and other descriptors for the font. For
# example:
# fonts:
# - family: Schyler
# fonts:
# - asset: fonts/Schyler-Regular.ttf
# - asset: fonts/Schyler-Italic.ttf
# style: italic
# - family: Trajan Pro
# fonts:
# - asset: fonts/TrajanPro.ttf
# - asset: fonts/TrajanPro_Bold.ttf
# weight: 700
#
# For details regarding fonts from package dependencies,
# see https://flutter.dev/custom-fonts/#from-packages
应用程序如下所示
【问题讨论】：
标签： android flutter dart switch-statement android-dark-theme