facebookAuthCredential.idToken 在 Flutter 中为 null

Question

我在 android 和 ios 中成功集成了 facebook 登录，我还在登录时获得了 facebook 访问令牌，但令牌 ID 为空。下面是代码

  Future<UserCredential> signInWithFacebook() async {
    // Trigger the sign-in flow
    final LoginResult loginResult = await FacebookAuth.instance.login();

    // Create a credential from the access token
    final OAuthCredential facebookAuthCredential =
        FacebookAuthProvider.credential(loginResult.accessToken!.token);
    print(facebookAuthCredential.idToken); //Here getting null

    // Once signed in, return the UserCredential
    return FirebaseAuth.instance.signInWithCredential(facebookAuthCredential);
  }

Answer 1

此时您不会通过 Facebook 身份验证流程获得 idToken，只会获得 accessToken。使用以下代码框架来管理 Facebook 登录并评估带有断点的特定行的结果：

Future<UserCredential> signInWithFacebook() async {
  final LoginResult loginResult = await FacebookAuth.instance.login();

  if (loginResult.status == LoginStatus.success) {
    final AccessToken accessToken = loginResult.accessToken!;
    final OAuthCredential credential =
        FacebookAuthProvider.credential(accessToken.token);
    try {
      return await FirebaseAuth.instance.signInWithCredential(credential);
    } on FirebaseAuthException catch (e) {
      // manage Firebase authentication exceptions
    } catch (e) {
      // manage other exceptions
    }
  } else {
      // login was not successful, for example user cancelled the process
  }
}

然后就可以用await调用这个函数了，以后完成后，就可以访问用户数据了：

final userCredential = await signInWithFacebook();
if (userCredential != null) {
    // here you will have your Firebase user in:
    // userCredential.user
    final idToken = userCredential.user!.getIdToken();
}