是的，这是正常的，onAuthStateChanged将继续触发，我通过使用以下代码解决了这个问题：

var authFlag = true;
  Firebase.onAuthStateChanged( user => {
    if(authFlag) {
      authFlag = false;
      if (user) {
        // Do something,
      }
      else {
        // Alert.alert("Auth Error")
      }
    }
  });

我能够通过在onAuthStateChanged侦听器中解析promise来解决这个问题。在我的例子中，我只对用户的ID令牌感兴趣。

const [request, response, promptAsync] = Google.useAuthRequest({
      androidClientId: "XXXXXXX",
      iosClientId: "XXXXXXX",
      expoClientId: "XXXXXXX",
  });

  const promptGoogleLogin = useCallback(() => {
    promptAsync().catch(console.error);
  }, [promptAsync]);

  const loginWithFirebaseIdToken = async (idToken: string) => {
    // Send idToken to the backend to authenticate user and return custom token
  };

  useEffect(() => {
    const handleResponse = async (response: AuthSessionResult) => {
        if (response.type === "success") {
            const { authentication } = response;

            const credential = GoogleAuthProvider.credential(
              authentication.idToken,
              authentication.accessToken
            );

            await signInWithCredential(firebaseAuth, credential);

            const idToken = await getUserIdToken();

            // Send Firebase token to my backend to continue auth flow
            loginWithFirebaseIdToken(idToken);
        }
    }

    if (response) {
        handleResponse(response);
    }
  }, [response]);

  // The secret ingredient
  const getUserIdToken = (): Promise<string> => {
    return new Promise((resolve) => {
      firebaseAuth.onAuthStateChanged((user) => {
        if (user) {
          user.getIdToken().then(resolve);
        }
      });
    });
  };