ios - 如何使用 webview 在 Xamarin.iOS 中实现手动 Facebook 登录

Question

我正在尝试在我的 Xamarin.iOS 应用程序中实现 Facebook 登录。我曾尝试使用 Xamarin.Auth 包，但有时用户无法处理并且此包存在一些问题。我发现最好的方法是对我的应用程序实现手动登录流程(使用 WebView )。目前，我已经在 Facebook 开发者门户中创建了一个应用程序，我可以从我的 iOS 应用程序访问该链接。

因此，用户将单击普通按钮，该按钮将转发到 Facebook 登录页面。我的问题是，如何从 Facebook 登录页面获取结果？以及如何获取用户 ID、电子邮件……？

目前的源代码如下:

partial void BtnFacebookLogin_TouchUpInside(UIButton sender)
    {
        NSUrl apiRequest =
            new NSUrl("https://www.facebook.com/dialog/oauth?client_id="
            + SharedResources.fbClientId
            + "&response_type=token&redirect_uri="
            + SharedResources.fbRedirectUrl);

        UIApplication.SharedApplication.OpenUrl(apiRequest);
    }

Answer 1

我通过使用Facebook SDK找到了答案，它被认为是目前最好的现有解决方案，下载官方SDK(Xamarin.Facebook.iOS)后，步骤如下:

1. 在 Info.plist 文件中，添加以下代码:

<key>NSAppTransportSecurity</key>
  <dict>
    <key>NSExceptionDomains</key>
    <dict>
      <key>facebook.com</key>
      <dict>
        <key>NSIncludesSubdomains</key>
        <true/>
        <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
        <false/>
      </dict>
      <key>fbcdn.net</key>
      <dict>
        <key>NSIncludesSubdomains</key>
        <true/>
        <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
        <false/>
      </dict>
      <key>akamaihd.net</key>
      <dict>
        <key>NSIncludesSubdomains</key>
        <true/>
        <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
        <false/>
      </dict>
    </dict>
  </dict>
  <key>LSApplicationQueriesSchemes</key>
  <array>
    <string>fbapi</string>
    <string>fbapi20130214</string>
    <string>fbapi20130410</string>
    <string>fbapi20130702</string>
    <string>fbapi20131010</string>
    <string>fbapi20131219</string>
    <string>fbapi20140410</string>
    <string>fbapi20140116</string>
    <string>fbapi20150313</string>
    <string>fbapi20150629</string>
    <string>fbauth</string>
    <string>fbauth2</string>
    <string>fb-messenger-api20140430</string>
    <string>fb-messenger-api</string>
    <string>fbauth2</string>
    <string>fbshareextension</string>
  </array>

1. 同样在 Info.plist 文件中，原始 View 、高级选项卡、URL 类型，以这种方式添加您的 Facebook 应用程序 ID“fb1112222......”。将“fb”保留在开头。

Pic: Facebook app ID in Info.plist

1. 在 AppDelegate.cs 中，覆盖这些方法:

       public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
       {
           // Override point for customization after application launch.
           // If not required for your application you can safely delete this method
   
           Profile.EnableUpdatesOnAccessTokenChange(true);
           Settings.AppID = "fb app id";
           Settings.DisplayName = "fb app name";
   
           // This method verifies if you have been logged into the app before, and keep you logged in after you reopen or kill your app.
           return ApplicationDelegate.SharedInstance.FinishedLaunching(application, launchOptions);
   
           //return true;
       }
   
       public override bool OpenUrl(UIApplication application, NSUrl url, string sourceApplication, NSObject annotation)
       {
           // We need to handle URLs by passing them to their own OpenUrl in order to make the SSO authentication works.
           return ApplicationDelegate.SharedInstance.OpenUrl(application, url, sourceApplication, annotation);
       }
   

2. 最后，这是Facebook的功能，你可以使用他们自己的按钮，也可以使用你的按钮。以我的方式，我使用了名称为 (BtnFacebookLogin) 的按钮。

   //这里是facebook函数

   私有(private)无效SetupFacebookLoginButton() { List readPermissions = new List { "public_profile", "email"};

           ////Set Up Button Design
           var fbBtnText = new NSAttributedString("login with facebook", new
               UIStringAttributes()
           {
               ForegroundColor = UIColor.White
           });
   
   
           BtnFacebookLogin.SetAttributedTitle(fbBtnText, UIControlState.Normal);
           BtnFacebookLogin.SetBackgroundImage(
               UIImage.FromBundle("btn_long_blue.png"), UIControlState.Normal);
   
           //Strat Login Functions
           Profile.Notifications.ObserveDidChange((sender, e) =>
           {
               if (e.NewProfile == null)
                   return;
   
               if (AccessToken.CurrentAccessToken != null)
               {
                   var request = new GraphRequest("/me?fields=name,email", null, AccessToken.CurrentAccessToken.TokenString, null, "GET");
                   request.Start((connection, result, error) =>
                   {
                       // Handle if something went wrong with the request
                       if (error != null)
                       {
                           showAlert("Error", error.Description);
                           return;
                       }
   
                       fbReponseFromSDK facebookSDKLoginItem = new fbReponseFromSDK();
                       // Get your profile name
                       var userInfo = result as NSDictionary;
                       if(userInfo["id"] != null)
                       { 
                           Console.WriteLine("id is: " + userInfo["id"].ToString());
                       }
                       if (userInfo["name"] != null)
                       { 
                           Console.WriteLine("name is: " + userInfo["name"].ToString());
                       }
                       if (userInfo["email"] != null)
                       { 
                           Console.WriteLine("email is: " + userInfo["email"].ToString());
                       }
                      //(Success) Do what you want next :
                       doneFacbookLogin();
                   });
               }
           });
   
           // Handle actions once the user is logged in
           BtnFacebookLogin.ReadPermissions = readPermissions.ToArray();
           BtnFacebookLogin.Completed += (sender, e) =>
           {
               if (e.Error != null)
               {
                   // Handle if there was an error
                   showAlert("Facebook Login", e.Error.Description);
                   return;
               }
   
               if (e.Result.IsCancelled)
               {
                   // Handle if the user cancelled the login request
                   //showAlert("Facebook Login", "Login Cancelled");
                   return;
               }
   
               showAlert("Facebook Login", "Login Successfull");
           };
   
           // Handle actions once the user is logged out
           BtnFacebookLogin.LoggedOut += (sender, e) =>
           {
               // Handle your logout
           };
   
           // If you have been logged into the app before, ask for the your profile name
           if (AccessToken.CurrentAccessToken != null)
           {
               var request = new GraphRequest("/me?fields=name,email", null, AccessToken.CurrentAccessToken.TokenString, null, "GET");
               request.Start((connection, result, error) =>
               {
                   // Handle if something went wrong with the request
                   if (error != null)
                   {
                       showAlert("Error", error.Description);
                       return;
                   }
   
                   // Get your profile name
   
               });
           }
       }
   

有关更多信息，请参阅他们在 GitHub 中的示例 (Link)