为什么Xamarin.Auth抛出认证错误OAuth1Authenticator和Twitter

我目前正在iOS项目上使用Xamarin.Auth来处理一些用户身份验证，通过我的应用程序中的Facebook和Twitter。使用OAuth2Authenticator进行Facebook身份验证的效果很好，我的实现主要基于文档（http://components.xamarin.com/gettingstarted/xamarin.auth）。但Twitter仍然使用OAuth1，因此我基于我的实现主要取决于此StackOverflow问题（https://stackoverflow.com/a/21982205）中的答案。一切工作正常，我能够检索用户，微博等，但毕竟代码执行后，我收到一个“身份验证错误”弹出屏幕上显示“对象引用未设置为对象的实例”。没有任何东西印在控制台上，但正如我迄今为止所看到的最常见的错误一样。我可以关闭弹出窗口，并且所有内容都会继续正确预览。我相信我已经将问题缩小到了OAuth1Authenticator请求的范围内，因为当所有其他处理代码都被注释掉时，我仍然收到错误。请参考下面的代码来查看可能的原因。为什么Xamarin.Auth抛出认证错误OAuth1Authenticator和Twitter

public override void ViewDidLoad() 
    { 
     base.ViewDidLoad(); 

     signupBtn.TouchUpInside += delegate { 
      LoginToTwitter(true, this); 
     }; 
    } 
    void LoginToTwitter(bool allowCancel, UIViewController _vc) 
    { 

     var auth = new OAuth1Authenticator (
      consumerKey: "My Consumer Key", 
      consumerSecret: "My Consumer Secret", 
      requestTokenUrl: new Uri("https://api.twitter.com/oauth/request_token"), 
      authorizeUrl: new Uri("https://api.twitter.com/oauth/authorize"), 
      accessTokenUrl: new Uri("https://api.twitter.com/oauth/access_token"), 
      callbackUrl: new Uri("My callback url"), 
      getUsernameAsync: (IDictionary<string, string> accountProperties) => { 
       string screen_name = ""; 
       if (accountProperties.TryGetValue("screen_name", out screen_name)) { 
        Console.WriteLine("SN: {0}", screen_name); 
        Account a = new Account(screen_name, accountProperties); 
        AuthenticatorCompletedEventArgs e = new AuthenticatorCompletedEventArgs(a); 
        TwitterCompleted(e, _vc); 
       } 
       return null;} 
     ); 
     auth.AllowCancel = allowCancel; 

     UIViewController authView = auth.GetUI(); 

     _vc.PresentViewController (authView, true, null); 
    } 
    void TwitterCompleted (AuthenticatorCompletedEventArgs e, UIViewController _vc) 
    { 
     var theAccount = e.Account; 
     var theProperties = theAccount.Properties; 
     foreach (var item in theProperties) { 
      Console.WriteLine (item); //debugging 
     } 
     InvokeOnMainThread (delegate { 
      _vc.DismissViewController (true, null); 
     }); 

     AccountStore.Create().Save (e.Account, "Twitter"); 

     if (!e.IsAuthenticated) { 
      Console.WriteLine("Not authorized"); 
      return; 
     } 

     theScreenName = e.Account.Properties["screen_name"]; 
     theCount = "2"; 

     IDictionary<string, string> theDict = new Dictionary<string, string>();; 
     theDict.Add("screen_name", theScreenName); 
     theDict.Add("count", theCount); 


     var request = new OAuth1Request("GET", new Uri("https://api.twitter.com/1.1/statuses/user_timeline.json"), theDict, e.Account, false); 
     request.GetResponseAsync().ContinueWith (t => { 
      if (t.IsFaulted) 
       Console.WriteLine("Error: {0}", t.Exception.InnerException.Message); 
      else if (t.IsCanceled) 
       Console.WriteLine("Canceled"); 
      else 
      { 
       var obj = JsonValue.Parse (t.Result.GetResponseText()); 
       Console.WriteLine("object: {0}", obj); // debugging 
      } 

     }, uiScheduler); 
     return; 
    } 
    private readonly TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext();

来源

2014-04-08 user3509501

你解决这个问题？ –

-1

，而不是返回在 “getUsernameAsync” 空返回任务

来源

2014-12-07 08:55:27

请详细解释你的答案！所以OP了解问题是什么以及解决方案如何工作。 – Rizier123

为什么Xamarin.Auth抛出认证错误OAuth1Authenticator和Twitter

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