解析Facebook登錄：用戶返回null和回調已經註冊爲<facebook>錯誤

Question

當前正在學習本教程「http://blog.grafixartist.com/facebook-login-with-parse-part-1/」和其他網頁的一些插件。

下面是我對LoginActivity代碼：

 public void parseFbLogin(){ 
     ParseFacebookUtils.initialize(this); 
     FacebookSdk.sdkInitialize(getApplicationContext()); 
     List<String> permissions = Arrays.asList("basic_info", "user_about_me", 
       "user_relationships", "user_birthday", "user_location"); 

       ParseFacebookUtils.logInWithReadPermissionsInBackground(LoginActivity.this, permissions, new LogInCallback() { 
        @Override 
        public void done(ParseUser user, ParseException err) { 
         if (user == null) { 
          Log.d("MyApp", "Uh oh. The user cancelled the Facebook login."); 
         } else if (user.isNew()) { 
          Log.d("MyApp", "User signed up and logged in through Facebook!"); 
         } else { 
          Log.d("MyApp", "User logged in through Facebook!"); 
//       getUserDetailsFromParse(); 
         } 
        } 
       }); 
    } 

    protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
     super.onActivityResult(requestCode, resultCode, data); 
     ParseFacebookUtils.onActivityResult(requestCode, resultCode, data); 
    } 

1.In ParseFbLogin，通常他們會回到我空但有時也能正常工作。 （允許註冊和登錄）。

2.每當我按第二次，應用程序將崩潰。以下是錯誤訊息

java.lang.IllegalStateException: Callback already registered for <facebook>: com.parse.ParseFacebookUtils$1@3f0d35a3 
      at com.parse.ParseAuthenticationManager.register(ParseAuthenticationManager.java:35) 
      at com.parse.ParseUser.registerAuthenticationCallback(ParseUser.java:1082) 
      at com.parse.ParseFacebookUtils$ParseUserDelegateImpl.registerAuthenticationCallback(ParseFacebookUtils.java:562) 
      at com.parse.ParseFacebookUtils.initialize(ParseFacebookUtils.java:109) 
      at com.parse.ParseFacebookUtils.initialize(ParseFacebookUtils.java:92) 
      at komi2015.shoppingu.Login.LoginActivity.parseFbLogin(LoginActivity.java:90) 
      at komi2015.shoppingu.Login.LoginActivity$4.onClick(LoginActivity.java:83) 
      at android.view.View.performClick(View.java:5254) 
      at android.view.View$PerformClick.run(View.java:21179) 
      at android.os.Handler.handleCallback(Handler.java:739) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:145) 
      at android.app.ActivityThread.main(ActivityThread.java:6843) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:372) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199) 

Answer 1

我找到了答案。 問題是因爲我初始化parsefacebook和facebooksdk在錯誤的類（我應該初始化應用程序）。