我收到以下错误 NoSuchMethodError was throw building Consumer(dirty, dependencies: [InheritedProvider]): This is the app.dart file
class App extends StatefulWidget {
@override
State<StatefulWidget> createState() {
return AppState();
}
}
class AppState extends State<App> with AfterLayoutMixin {
final _app = AppModel();
final _product = ProductModel();
final _wishlist = WishListModel();
final _shippingMethod = ShippingMethodModel();
final _paymentMethod = PaymentMethodModel();
final _order = OrderModel();
final _search = SearchModel();
final _recent = RecentModel();
final _user = UserModel();
@override
void afterFirstLayout(BuildContext context) {
Services().setAppConfig(serverConfig);
_app.loadAppConfig();
}
@override
Widget build(BuildContext context) {
print("[AppState] build");
return ChangeNotifierProvider<AppModel>.value(
value: _app,
child: Consumer<AppModel>(
builder: (context, value,child) {
return MultiProvider(
providers: [
Provider<ProductModel>.value(value: _product),
Provider<WishListModel>.value(value: _wishlist),
Provider<ShippingMethodModel>.value(value: _shippingMethod),
Provider<PaymentMethodModel>.value(value: _paymentMethod),
Provider<OrderModel>.value(value: _order),
Provider<SearchModel>.value(value: _search),
Provider<RecentModel>.value(value: _recent),
ChangeNotifierProvider(builder: (context)=> UserModel()),
ChangeNotifierProvider(builder: (context)=> CartModel()),
ChangeNotifierProvider(builder: (context)=> CategoryModel()),
],
child: MaterialApp(
debugShowCheckedModeBanner: false,
locale: new Locale(Provider.of<AppModel>(context).locale, ""),
navigatorObservers: [
FirebaseAnalyticsObserver(analytics: analytics),
],
localizationsDelegates: [
S.delegate,
GlobalMaterialLocalizations.delegate,
GlobalMaterialLocalizations.delegate,
GlobalCupertinoLocalizations.delegate,
DefaultCupertinoLocalizations.delegate,
],
supportedLocales: S.delegate.supportedLocales,
localeListResolutionCallback:
S.delegate.listResolution(fallback: const Locale("en","")),
home: SplashScreenAnimate(),
routes: <String, WidgetBuilder>{
"/home": (context) => MainTabs(),
"/login": (context) => LoginScreen(),
"/register": (context) => RegistrationScreen(),
'/products': (context) => ProductsPage(),
'/wishlist': (context) => WishList(),
'/checkout': (context) => Checkout(),
'/orders': (context) => MyOrders(),
'/onboardscreen': (context) => OnBoardScreen(),
'/blogs': (context) => BlogScreen(),
'/notify': (context) => Notifications()
},
theme: Provider.of<AppModel>(context).darkTheme
? buildDarkTheme().copyWith(
primaryColor:
HexColor(_app.appConfig["Setting"]["MainColor"]))
: buildLightTheme().copyWith(
primaryColor:
HexColor(_app.appConfig["Setting"]["MainColor"])),
),
);
},
),
);
}
运行时错误是
The relevant error-causing widget was:
Consumer<AppModel> file:///E:/MVS/Cossetpack/lib/app.dart:202:14
When the exception was thrown, this was the stack:
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1 AppState.build.<anonymous closure> (package:fstore/app.dart:252:42)
#2 Consumer.build (package:provider/src/consumer.dart:180:19)
#3 StatelessElement.build (package:flutter/src/widgets/framework.dart:4620:28)
#4 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4546:15)
#5 Element.rebuild (package:flutter/src/widgets/framework.dart:4262:5)
#6 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4525:5)
#7 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4520:5)
... Normal element mounting (23 frames)
#30 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3490:14)
#31 Element.updateChild (package:flutter/src/widgets/framework.dart:3258:18)
#32 RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:1174:16)
#33 RenderObjectToWidgetElement.mount (package:flutter/src/widgets/binding.dart:1145:5)
#34 RenderObjectToWidgetAdapter.attachToRenderTree.<anonymous closure> (package:flutter/src/widgets/binding.dart:1087:17)
#35 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2620:19)
#36 RenderObjectToWidgetAdapter.attachToRenderTree (package:flutter/src/widgets/binding.dart:1086:13)
#37 WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:927:7)
#38 WidgetsBinding.scheduleAttachRootWidget.<anonymous closure> (package:flutter/src/widgets/binding.dart:908:7)
(elided 11 frames from class _RawReceivePortImpl, class _Timer, dart:async, and dart:async-patch)
════════════════════════════════════════════════════════════════════════════════════════════════════
════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
The following NoSuchMethodError was thrown building Consumer<AppModel>(dirty, dependencies: [InheritedProvider<AppModel>]):
The method '[]' was called on null.
Receiver: null
Tried calling: []("Setting")
The relevant error-causing widget was:
Consumer<AppModel> file:///E:/MVS/Cossetpack/lib/app.dart:202:14
When the exception was thrown, this was the stack:
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1 AppState.build.<anonymous closure> (package:fstore/app.dart:252:42)
#2 Consumer.build (package:provider/src/consumer.dart:180:19)
#3 StatelessElement.build (package:flutter/src/widgets/framework.dart:4620:28)
#4 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4546:15)
...
════════════════════════════════════════════════════════════════════════════════════════════════════
Another exception was thrown: 'dart:ui/window.dart': Failed assertion: line 285: '<optimized out>': is not true.
════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
'dart:ui/window.dart': Failed assertion: line 285: '<optimized out>': is not true.
The relevant error-causing widget was:
Consumer<AppModel> file:///E:/MVS/Cossetpack/lib/app.dart:202:14
════════════════════════════════════════════════════════════════════════════════════════════════════
这是应用模型
class AppModel with ChangeNotifier {
MagentoApi _magentoApi = MagentoApi();
Map<String, dynamic> appConfig;
bool isLoading = true;
String message;
bool darkTheme = false;
String locale = "en";
String productListLayout;
bool showDemo = false;
String username;
bool isInit = false;
String currency;
Map<String, dynamic> currencyRate = Map<String, dynamic>();
AppModel() {
getConfig();
}
Future<bool> getConfig() async {
try {
SharedPreferences prefs = await SharedPreferences.getInstance();
locale = prefs.getString("language") ?? kAdvanceConfig['DefaultLanguage'];
darkTheme = prefs.getBool("darkTheme") ?? false;
currency = prefs.getString("currency") ??
(kAdvanceConfig['DefaultCurrency'] as Map)['currency'];
isInit = true;
return true;
} catch (err) {
return false;
}
}
void changeLanguage(String country, BuildContext context) {
locale = country;
Provider.of<CategoryModel>(context).getCategories(lang: country);
notifyListeners();
}
void updateTheme(bool theme) {
darkTheme = theme;
notifyListeners();
}
void updateShowDemo(bool value) {
showDemo = value;
notifyListeners();
}
void updateUsername(String user) {
username = user;
notifyListeners();
}
void loadStreamConfig(config) {
appConfig = config;
productListLayout = appConfig['Setting']['ProductListLayout'];
isLoading = false;
notifyListeners();
}
void loadAppConfig() async {
try {
if (kAppConfig.indexOf('http') != -1) {
// load on cloud config and update on air
final appJson = await http.get(Uri.encodeFull(kAppConfig),
headers: {"Accept": "application/json"});
appConfig = convert.jsonDecode(appJson.body);
} else {
// load local config
final appJson = await rootBundle.loadString(kAppConfig);
appConfig = convert.jsonDecode(appJson);
}
productListLayout = appConfig['Setting']['ProductListLayout'];
if (serverConfig["type"] == "magento") {
_magentoApi.getAllAttributes();
}
if (serverConfig["type"] == "woo" && kAdvanceConfig['isCaching']) {
final configCache = await Services().getHomeCache();
if (configCache != null) {
appConfig = configCache;
}
}
isLoading = false;
notifyListeners();
} catch (err) {
isLoading = false;
message = err.toString();
notifyListeners();
}
}
void updateProductListLayout(layout) {
productListLayout = layout;
notifyListeners();
}
}
class App {
Map<String, dynamic> appConfig;
App(this.appConfig);
}
在添加消费者小部件之前它工作正常，但现在我必须添加应用程序结帐功能，我已经添加了代码，但我收到错误请建议我在哪里做错了