未处理的异常：NoSuchMethodError：在 null [GoogleAPI + YoutubeAPI + Firebase + Flutter] 上调用了 getter 'authentication'

Question

我正面临这个问题，看起来我的 auth var 为空，但我没有发现任何问题。错误：

E/flutter (24944): [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: NoSuchMethodError: The getter 'authentication' was called on null.
E/flutter (24944): Receiver: null
E/flutter (24944): Tried calling: authentication
E/flutter (24944): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)

我的代码（只是有问题的函数）：

  addPlayListItem(String videoID, String playlistID) async {
    final String apiUrl =
        "https://www.googleapis.com/youtube/v3/playlistItems?part=snippet";
    final FirebaseAuth _auth = FirebaseAuth.instance;
    final GoogleSignIn googleSignIn = GoogleSignIn(
      scopes: [
        'email',
        'profile',
        'https://www.googleapis.com/auth/youtube',
      ],
    );

    final GoogleSignInAccount googleSignInAccount = await googleSignIn.signInSilently();
    final GoogleSignInAuthentication googleSignInAuthentication =
    await googleSignInAccount.authentication;

    final AuthCredential credential = GoogleAuthProvider.getCredential(
        idToken: googleSignInAuthentication.idToken,
        accessToken: googleSignInAuthentication.accessToken);

    final AuthResult authResult = await _auth.signInWithCredential(credential);
    final FirebaseUser user = authResult.user;

    assert(!user.isAnonymous);
    assert(await user.getIdToken() != null);

    final FirebaseUser currentUser = await _auth.currentUser();
    assert(currentUser.uid == user.uid);

    void signOutGoogle() async {
      await googleSignIn.signOut();
    }

    print("token  " +
        googleSignInAuthentication.accessToken); // accessToken not idToken

    final response = await http.post(
      apiUrl,
      headers: {
        "Authorization": "Bearer ${googleSignInAuthentication.accessToken}",
        // Use access token and add a space after the 'Bearer
        "Accept": "application/json",
      },
      body: jsonEncode({
        "snippet": {
          "playlistId": "" + playlistID,
          "resourceId": {"kind": "youtube#video", "videoId": "" + videoID}
        }
      }),
    );
    if (response.statusCode == 200) {
      print("Song was added to playlist");
    } else {
      print(response.body);
      print("Failture song wasn't added to playlist");
    }
  }

这是我在 iOS 设备上尝试使用该功能时得到的错误代码。也许这会提供更多信息。

2021-09-11 11:58:53.310702+0200 Runner[6447:55089] flutter: {
  "error": {
    "code": 403,
    "message": "Request had insufficient authentication scopes.",
    "errors": [
      {
        "message": "Insufficient Permission",
        "domain": "global",
        "reason": "insufficientPermissions"
      }
    ],
    "status": "PERMISSION_DENIED"
  }
}
2021-09-11 11:58:53.310854+0200 Runner[6447:55089] flutter: Failture song wasn't added to playlist

我好像遇到了身份验证问题，但我不知道从哪里开始。

更新安卓： 干净的重建后，我得到了这个错误代码

E/flutter ( 3537): [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: PlatformException(sign_in_failed, com.google.android.gms.common.api.ApiException: 12500: , null, null)
E/flutter ( 3537): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:597:7)
E/flutter ( 3537): #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:158:18)
E/flutter ( 3537): <asynchronous suspension>
E/flutter ( 3537): #2      MethodChannel.invokeMapMethod (package:flutter/src/services/platform_channel.dart:358:43)
E/flutter ( 3537): <asynchronous suspension>
E/flutter ( 3537): #3      GoogleSignIn._callMethod (package:google_sign_in/google_sign_in.dart:233:30)
E/flutter ( 3537): <asynchronous suspension>
E/flutter ( 3537): #4      GoogleSignIn.signIn.isCanceled (package:google_sign_in/google_sign_in.dart)
E/flutter ( 3537): <asynchronous suspension>
E/flutter ( 3537): 

Answer 1

来自signInSilently 方法的文档：

尝试登录之前已通过身份验证的用户，而无需 互动。

返回的 Future 解析为 GoogleSignInAccount 的实例 登录成功或null，如果之前没有经过身份验证 用户。使用signIn方法触发交互式登录过程。

所以您将googleSignInAccount 设为null，因为之前没有登录用户。

您可以添加检查以查看googleSignInAccount 是否为null，如果为真则使用signIn。

所以你可以更新这个：

...
final GoogleSignInAccount googleSignInAccount = await googleSignIn.signInSilently();
...

到这里：

...
GoogleSignInAccount googleSignInAccount = await googleSignIn.signInSilently();

if (googleSignAccount == null) {
  googleSignInAccount = await googleSignIn.signIn();
}
...