I'm trying to retrieve data from firestore database. But there's an exception throwing to me saying:

PlatformException
code: 'null-error'
message: 'Host platform returned null value for non-null return value.

Here's my main.dart

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(
    MaterialApp(
      home: const Screen1(),      
    ),
  );
}

And here's my screen_1.dart

class Screen1 extends StatefulWidget {
  const Screen1({Key? key}) : super(key: key);

  @override
  State<Screen1> createState() => _Screen1State();
}

class _Screen1State extends State<Screen1> {
  List<String> student = [];

  Future getStudent() async {
    await FirebaseFirestore.instance.collection('student_Info').get().then(
          (snapshot) => snapshot.docs.forEach(
            (document) {                  
              print(document.reference);
            },
          ),
        );
  }

  @override
  void initState() {
    getStudent();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold();
  }
}

At first I called flutterfire configure in terminal and select a project. Then I created collection. And also I changed minsdkversion to 21 in \android\app\build.gradle. What's wrong with my code???

Appreciate if someone can advise. Thank you in advance!

CodePudding user response：

If you've configure flutterfire cli well then all you have to do is import and use it in the options like this:

...
import 'firebase_options.dart';

...
void main(){
...
await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
}
...

CodePudding user response：

First, you need to run flutterfire configure in the terminal, it will automatically generate the firebase_options.dart file. Then you can try the following code:

import 'firebase_options.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
  runApp(
    MaterialApp(
      home: const Screen1(),      
    ),
  );
}