我设法使用路由在页面之间移动来使一些代码正常工作。现在我正在尝试实现传递参数（将此作为我的参考：https://docs.flutter.dev/cookbook/navigation/navigate-with-arguments），但我收到以下错误，请问有人可以吗给我指明正确的方向吗？
非常感谢
代码：
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
runApp(const Home());
}
class Home extends StatelessWidget {
const Home({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
routes: {
'/': (context) => ItemList(),
'/factfile': (context) => ItemDetails(),
ExtractArgumentsScreen.routeName: (context) => const ExtractArgumentsScreen(),
},
);
}
}
class ItemList extends StatelessWidget {
ItemList({Key? key}) : super(key: key) {
_stream = _reference.snapshots();
}
CollectionReference _reference = FirebaseFirestore.instance.collection('example_table_name');
late Stream<QuerySnapshot> _stream;
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Item List'),
),
body: StreamBuilder<QuerySnapshot>(
stream: _stream,
builder: (BuildContext context, AsyncSnapshot snapshot) {
//Check error
if (snapshot.hasError) {
return Center(child: Text('Some error occurred ${snapshot.error}'));
}
//Check if data arrived
if (snapshot.hasData) {
//get the data
QuerySnapshot querySnapshot = snapshot.data;
List<QueryDocumentSnapshot> documents = querySnapshot.docs;
//Convert the documents to Maps
List<Map> items = documents.map((e) =>
{
'name': e['name'],
'dlastupd': e['dlastupd'],
'dlastupd date': DateTime.fromMillisecondsSinceEpoch(e['dlastupd'] * 1000)
}).toList();
// sort in descending date order
items.sort((a, b) => b["dlastupd"].compareTo(a["dlastupd"]));
//Display the list
return ListView.builder(
itemCount: items.length,
itemBuilder: (BuildContext context, int index) {
//Get the item at this index
Map thisItem = items[index];
//Return the widget for the list items
return ListTile(
title: Text(formatDate(thisItem['dlastupd date'], [dd, '', M]) + " - " + thisItem['name']),
onTap: () {
Navigator.pushNamed(
context,
'/factfile',
arguments: ScreenArguments(
'id': 'example_record_id_number',
),
);
},
);
});
}
//Show loader
return Center(child: CircularProgressIndicator());
},
), //Display a list // Add a FutureBuilder
);
}
}
class ItemDetails extends StatelessWidget {
const ExtractArgumentsScreen({super.key}); // !!! This line causes an error !!!
static const routeName = '/extractArguments';
ItemDetails(this.itemId, {Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
// Extract the arguments from the current ModalRoute
// settings and cast them as ScreenArguments.
final args = ModalRoute.of(context)!.settings.arguments as ScreenArguments;
final DocumentReference docRef = FirebaseFirestore.instance.collection("example_table_name").doc(args.id);
return Scaffold(
appBar: AppBar(
title: Text("Item Details"),
),
body: FutureBuilder<DocumentSnapshot>(
future: docRef.get(),
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(
child: CircularProgressIndicator(),
);
} else if (snapshot.hasError) {
return Center(
// child: Text("Error: ${snapshot.error}"),
child: Text("Oh no it's an error"),
);
} else {
final data = snapshot.data!.data() as Map<String, dynamic>;
return Center(
child: Text(data["name"]),
);
}
},
),
);
}
}
class ScreenArguments {
final String id;
ScreenArguments(this.id);
}
错误：
lib/main.dart:118:3: Error: Getters, setters and methods can't be declared to be 'const'.
Try removing the 'const' keyword.
const ExtractArgumentsScreen({super.key}); // !!! This line causes an error !!!
^^^^^
lib/main.dart:117:7: Error: The non-abstract class 'ItemDetails' is missing implementations for these members:
- ItemDetails.ExtractArgumentsScreen
Try to either
- provide an implementation,
- inherit an implementation from a superclass or mixin,
- mark the class as abstract, or
- provide a 'noSuchMethod' implementation.
class ItemDetails extends StatelessWidget {
^^^^^^^^^^^
lib/main.dart:118:9: Context: 'ItemDetails.ExtractArgumentsScreen' is defined here.
const ExtractArgumentsScreen({super.key}); // !!! This line causes an error !!!
^^^^^^^^^^^^^^^^^^^^^^
lib/main.dart:38:46: Error: Too few positional arguments: 1 required, 0 given.
'/factfile': (context) => ItemDetails(),
^
lib/main.dart:123:3: Context: Found this candidate, but the arguments don't match.
ItemDetails(this.itemId, {Key? key}) : super(key: key);
^^^^^^^^^^^
lib/main.dart:39:62: Error: Couldn't find constructor 'ExtractArgumentsScreen'.
ExtractArgumentsScreen.routeName: (context) => const ExtractArgumentsScreen(),
^^^^^^^^^^^^^^^^^^^^^^
lib/main.dart:39:9: Error: The getter 'ExtractArgumentsScreen' isn't defined for the class 'Home'.
- 'Home' is from 'package:firestore_connection_test/main.dart' ('lib/main.dart').
Try correcting the name to the name of an existing getter, or defining a getter or field named 'ExtractArgumentsScreen'.
ExtractArgumentsScreen.routeName: (context) => const ExtractArgumentsScreen(),
^^^^^^^^^^^^^^^^^^^^^^
lib/main.dart:101:27: Error: Expected an identifier, but got ''id''.
Try inserting an identifier before ''id''.
'id': 'example_record_id_number',
^^^^
lib/main.dart:118:33: Error: Super-initializer formal parameters can only be used in generative constructors.
Try removing 'super.'.
const ExtractArgumentsScreen({super.key}); // !!! This line causes an error !!!
^^^^^
lib/main.dart:123:20: Error: 'itemId' isn't an instance field of this class.
ItemDetails(this.itemId, {Key? key}) : super(key: key);
^^^^^^
我确实尝试参考https://docs.flutter.dev/cookbook/navigation/navigate-with-arguments和我原来的帖子（没有NamedRoutes中的参数）Flutter：如何显示来自firebase的值获取查询？
你可以尝试一下我在我的项目中使用的这个方法
import 'package:flutter/material.dart';
void main() async {
WidgetsFlutterBinding.ensureInitialized();
runApp(const Home());
}
class Home extends StatelessWidget {
const Home({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: first(),
onGenerateRoute: Router.onRouteGenerator,
);
}
}
class Router {
static MaterialPageRoute onRouteGenerator(settings) {
switch (settings.name) {
case second.routeName:
return MaterialPageRoute(
settings: settings,
builder: (_) => second(
title: settings.arguments as String,
),
);
default:
return MaterialPageRoute(
settings: settings,
builder: (_) => const Material(
child: Center(
child: Text("404 page not founded"),
),
),
);
}
}
}
class first extends StatelessWidget {
const first({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: GestureDetector(
onTap: () {
Navigator.pushNamed(context, '/second', arguments: "test");
},
child: Container(
height: 100,
width: 100,
color: Colors.grey,
))),
);
}
}
class second extends StatelessWidget {
static const routeName = '/second';
final String title;
const second({Key? key, required this.title}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Container(
height: 100, width: 100, color: Colors.grey, child: Text(title))),
);
}
}