在我切换到named routes我的应用程序在使用时正常工作的位置后出现此错误MaterialPageRoute：
主要飞镖：
void main() {
WidgetsFlutterBinding.ensureInitialized();
runApp(
MultiProvider(
providers: [
ChangeNotifierProvider(create: (context) => ClassA()),
ChangeNotifierProvider(
create: (context) => ClassB()),
],
child: MyApp(),
),
);
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return FutureBuilder(
future: Firebase.initializeApp(),
builder: (context, snapshot) {
if (snapshot.hasError) {
return ...
}
if (snapshot.connectionState == ConnectionState.done) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'App Title',
initialRoute: '/',
routes: {
'/': (context) => Wrapper(),
'somePage/': (context) => SomePage(),
},
);
}
//else ...
return ... ;
});
}
}
错误信息：
The following _CastError was thrown building Builder(dirty):
Null check operator used on a null value
The relevant error-causing widget was:
MaterialApp file:///.../lib/main.dart:40:20
When the exception was thrown, this was the stack:
#0 _WidgetsAppState._onGenerateRoute.<anonymous closure> (package:flutter/src/widgets/app.dart:1196:48)
#1 MaterialPageRoute.buildContent (package:flutter/src/material/page.dart:54:55)
#2 MaterialRouteTransitionMixin.buildPage (package:flutter/src/material/page.dart:107:27)
#3 _ModalScopeState.build.<anonymous closure>.<anonymous closure> (package:flutter/src/widgets/routes.dart:840:53)
#4 Builder.build (package:flutter/src/widgets/basic.dart:7555:48)
颤振医生：
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 2.0.2, on Microsoft Windows [Version 10.0.19042.867], locale en-US)
[√] Android toolchain - develop for Android devices (Android SDK version 30.0.1)
[√] Chrome - develop for the web
[√] Android Studio (version 4.1.0)
[√] VS Code (version 1.52.1)
[√] Connected device (3 available)
• No issues found!
奇怪的是，该应用程序在多次热重启后工作，然后热重启使其崩溃。