Facebook的訪問令牌總是空

Question

我有我的主要活動一些代碼，調用我的Facebook登錄活動類，如果AccessToken.getCurrentAccessToken（）爲null：

import android.content.Intent; 
import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.util.Log; 
import android.widget.Toast; 

import com.facebook.AccessToken; 
import com.facebook.AccessTokenTracker; 
import com.facebook.CallbackManager; 
import com.facebook.FacebookCallback; 
import com.facebook.FacebookException; 
import com.facebook.Profile; 
import com.facebook.ProfileTracker; 
import com.facebook.login.LoginManager; 
import com.facebook.login.LoginResult; 

import java.util.Arrays; 

import matthewboyle.lurker_android.MainFeedScreen; 
import matthewboyle.lurker_android.utilities.ConnectionChecker; 

/** 
* Created by matthewboyle on 28/05/2017. 
*/ 

public class FacebookLogin extends AppCompatActivity { 
    private CallbackManager mCallbackManager; 
    private AccessTokenTracker accessTokenTracker; 
    private ProfileTracker profileTracker; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     mCallbackManager = CallbackManager.Factory.create(); 
     accessTokenTracker = new AccessTokenTracker() { 
      @Override 
      protected void onCurrentAccessTokenChanged(AccessToken oldAccessToken, AccessToken currentAccessToken) { 
       Log.d("facebook", "onCurrentAccessTokenChanged"); 


      } 
     }; 
     profileTracker = new ProfileTracker() { 
      @Override 
      protected void onCurrentProfileChanged(Profile oldProfile, Profile currentProfile) { 
       Log.d("facebook", "onCurrentProfileChanged"); 

      } 
     }; 
     accessTokenTracker.startTracking(); 
     profileTracker.startTracking(); 

     LoginManager.getInstance().registerCallback(mCallbackManager, 
       new FacebookCallback<LoginResult>() { 
        @Override 
        public void onSuccess(LoginResult loginResult) { 
         Log.d("facebook", "in on success"); 
         AccessToken accessToken = loginResult.getAccessToken(); 
         Log.d("permissions", accessToken.getPermissions().toString()); 

         Log.d("facebook", "in on success,got a token and its "+accessToken); 

        } 

        @Override 
        public void onCancel() { 
         Log.d("facebook", "in cancel"); 

        } 

        @Override 
        public void onError(FacebookException exception) { 
         Log.d("facebook", "in error"); 
         Log.d("facebook", exception.toString()); 




        } 


       }); 
     LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("public_profile", "user_posts","user_likes","user_about_me","user_managed_groups","user_tagged_places")); 
     Log.d("facebook", "Done so redirecting with "+AccessToken.getCurrentAccessToken()); 

     startActivity(new Intent(FacebookLogin.this,MainFeedScreen.class)); 


    } 
    @Override 
    protected void onActivityResult(int requestCode, int responseCode, Intent intent) { 
     super.onActivityResult(requestCode, responseCode, intent); 
     //Facebook login 
     mCallbackManager.onActivityResult(requestCode, responseCode, intent); 

    } 
} 

如果我運行此代碼，唯一的打印語句我得到的是：

Done so redirecting with null 

它似乎沒有擊中任何其他類的方法。

值得一提的是，此代碼工作正常，直到我重新安裝應用程序。我去了Facebook並在我的應用中更新了哈希鍵，但這似乎沒有幫助。但是，我沒有看到任何由於散列鍵造成的錯誤。

希望有任何幫助。

Answer 1

你需要移動「startActivity」你行「的onSuccess」回調裏面是這樣的：

LoginManager.getInstance().registerCallback(mCallbackManager, 
      new FacebookCallback<LoginResult>() { 
       @Override 
       public void onSuccess(LoginResult loginResult) { 
        Log.d("facebook", "in on success"); 
        AccessToken accessToken = loginResult.getAccessToken(); 
        Log.d("permissions", accessToken.getPermissions().toString()); 

        Log.d("facebook", "in on success,got a token and its "+accessToken); 

        Log.d("facebook", "Done so redirecting with "+AccessToken.getCurrentAccessToken()); 

        startActivity(new Intent(FacebookLogin.this,MainFeedScreen.class)); 

       } 

       @Override 
       public void onCancel() { 
        Log.d("facebook", "in cancel"); 

       } 

       @Override 
       public void onError(FacebookException exception) { 
        Log.d("facebook", "in error"); 
        Log.d("facebook", exception.toString()); 




       } 


      }); 

Answer 2

我使用Fb SDK 4.1與此代碼段爲我工作：

而作爲@Duda提到您需要在「onSuccess」回調中移動「startActivity」行。

@Override 
public void onSuccess(LoginResult loginResult) { 

    AccessToken accessToken = loginResult.getAccessToken(); 

    Log.d("facebook", "Done so redirecting with "+accessToken.getToken()); 

    startActivity(new Intent(FacebookLogin.this,MainFeedScreen.class)); 

}