firebase - Firestore上的空uid尝试使用Flutter和Firebase保存数据

Question

当用户注册时，我试图保存一些数据，但是我可能没有调用FirebaseUser权限。有什么建议么？

码:

String errorMessage;
  String name;
  String password;
  String email;
  String role;
  bool obscure = true;
  FirebaseUser instructor;

  final FirebaseAuth _auth = FirebaseAuth.instance;

  final db = Firestore.instance;

  void saveData() async {
    await db.collection("instructori")
      .document(instructor.uid)
      .setData(
        {
          'Nume': name,
          'Rol': role,
          'Email': email,
          'Parola': password,
          'UID': instructor.uid
        }
      );
  }


  Future<void> registerUser() async {
    instructor = await _auth
        .createUserWithEmailAndPassword(
      email: email,
      password: password,
    ).then((onValue) {
      saveData();
      Navigator.of(context).pushNamed(ClientiPage.id);
    }).catchError((error) {
      errorMessage = error;
    });



    Navigator.of(context).pushNamed(ClientiPage.id);
  }

用户成功通过了身份验证，但是我看不到数据被保存到Firestore树中。我在控制台中完成了所有工作，因此我假设这是代码。

错误:

E/flutter ( 5527): Tried calling: uid
E/flutter ( 5527): #0      Object.noSuchMethod  (dart:core-patch/object_patch.dart:53:5)
E/flutter ( 5527): #1      _RegisterPageState.saveData 
package:euroswimming_instructori/register_page.dart:29
E/flutter ( 5527): #2      _RegisterPageState.registerUser.<anonymous closure> 
package:euroswimming_instructori/register_page.dart:48
E/flutter ( 5527): #3      _rootRunUnary  (dart:async/zone.dart:1134:38)

Answer 1

.then()返回的是另一个Future<void>，因此instructor被设置为null。您可以像这样在instructor回调中设置.then():

void registerUser() {
  _auth.createUserWithEmailAndPassword(
    email: email,
    password: password,
  ).then((result) {
    instructor = result.user;
    saveData();
    Navigator.of(context).pushNamed(ClientiPage.id);
  }).catchError((error) {
    errorMessage = error;
  });

  Navigator.of(context).pushNamed(ClientiPage.id);
}