在颤动中使用 FirebaseAuth verifyPhoneNumber？

Question

嘿，我正在尝试在 Flutter 中使用 Firebase Auth verifyPhoneNumber。

我经常将onTap 中的msg 函数设为null。我尝试在 registerToFb 函数中声明一个变量，但我无法更新它的值。我该如何解决？

以下是我调用 firebaseAuth.verifyPhoneNymber() 方法的函数。

onTap: () async {
       setState(() => isLoading = true);
       String msg = await _auth.registerToFb(
        "+91$truephoneNumber", context);
       print(msg);

    },

以下是我定义我的功能的地方。

class AuthenticationService {
  final FirebaseAuth _firebaseAuth;

  AuthenticationService(this._firebaseAuth);

  Future registerToFb(String phoneNumber, BuildContext context) async {
    String result = " ";
    await _firebaseAuth.verifyPhoneNumber(
      phoneNumber: phoneNumber,
      timeout: const Duration(seconds: 30),
      verificationCompleted: (PhoneAuthCredential credential) async {
        UserCredential authresult =
            await _firebaseAuth.signInWithCredential(credential);

        User user = authresult.user;
        _getUserFromFirebase(user);
        result =  "signedUp";
      },
      verificationFailed: (FirebaseAuthException e) {
        String error = e.code == 'invalid-phone-number'
            ? "Invalid number. Enter again."
            : "Can Not Login Now. Please try again.";
        result = error;
      },
      codeSent: (String verificationId, int resendToken) {
       
        result = "verified";
      },
      codeAutoRetrievalTimeout: (String verificationId) {},
    );
  }
  return result;
}

请帮帮我。谢谢

Answer 1

问题是您没有在函数中返回任何内容。即使您尝试从回调内部保存值，verifyPhoneNumber 的未来也会在这些回调被调用之前解析。

你需要等待正确的事情。你不应该等待从verifyPhoneNumber 返回的未来。您应该等待一个无法解决的新未来，直到您从其中一个回调中获得结果。这意味着您需要创建自己的Future，您可以在需要时专门手动解决它。您可以使用Completer：

Future<String> registerToFb(String phoneNumber, BuildContext context) {
  final completer = Completer<String>();

  _firebaseAuth.verifyPhoneNumber(
    phoneNumber: phoneNumber,
    timeout: const Duration(seconds: 30),
    verificationCompleted: (PhoneAuthCredential credential) async {
      UserCredential authresult =
          await _firebaseAuth.signInWithCredential(credential);

      User user = authresult.user;
      _getUserFromFirebase(user);
      completer.complete("signedUp");
    },
    verificationFailed: (FirebaseAuthException e) {
      String error = e.code == 'invalid-phone-number'
          ? "Invalid number. Enter again."
          : "Can Not Login Now. Please try again.";
      completer.complete(error);
    },
    codeSent: (String verificationId, int resendToken) {
      completer.complete("verified");
    },
    codeAutoRetrievalTimeout: (String verificationId) {
      completer.complete("timeout");
    },
  );

  return completer.future;
}