在Android中登录Facebook后，会话在OnActivityResult方法中为空

Question

I am trying to implement the login functionality using facebook and after successful login i have to fetch couple of information of the user. Now for login i wrote some code. When i am pressing log in button, it is opening facebook, fetching the login info from the facebook native app and login also without error. But after that it is coming back to my application's login page and in the OnActivityResult() method, session is becoming null. So i am not able to get the details. I have written the below code:

      if(view == mBtnFacebook)
        {
               Session currentSession = Session.getActiveSession();
                if (currentSession == null || currentSession.getState().isClosed()) {
                    Session session = new Session.Builder(LoginScreen.this).build();
                    Session.setActiveSession(session);
                    currentSession = session;
                }

                if (currentSession.isOpened()) {
                    // Do whatever u want. User has logged in
                     Log.d("Testing", "current session is opened already  ");

                } else if (!currentSession.isOpened()) {
                    // Ask for username and password

//                  currentSession.openForRead(new Session.OpenRequest(this).setCallback(statusCallback);
                    OpenRequest op = new Session.OpenRequest((Activity) this);

                    op.setLoginBehavior(SessionLoginBehavior.SSO_WITH_FALLBACK);
                    op.setCallback(null);

                    List<String> permissions = new ArrayList<String>();
                    permissions.add("email");
                    op.setPermissions(permissions);

                    Session s = new Session(LoginScreen.this);//new Builder(LoginScreen.this).build();
                    Session.setActiveSession(s);
                    s.openForPublish(op);
                }
                }

                public void call(Session session, SessionState state, Exception exception) {
            }

            @Override
            public void onActivityResult(int requestCode, int resultCode, Intent data) {
                super.onActivityResult(requestCode, resultCode, data);
                Log.d("Testing", "in onActivityResult");
                if (Session.getActiveSession() != null)
                    Session.getActiveSession().onActivityResult(this, requestCode,
                            resultCode, data);

                Session currentSession = Session.getActiveSession();
                if (currentSession == null || currentSession.getState().isClosed()) {
                    Log.d("Testing", "current session null");
                    Session session1 = new Session.Builder(getBaseContext()).build();
                    Session.setActiveSession(session1);
                    currentSession = session1;
                }

                if (currentSession.isOpened()) {
                    Log.d("Testing", "current session already opened");
                    Session.openActiveSession(this, true, new Session.StatusCallback() {

                        @Override
                        public void call(final Session session, SessionState state,
                                Exception exception) {

                            if (session.isOpened()) {

                                Request.executeMeRequestAsync(session,
                                        new Request.GraphUserCallback() {

                                            @Override
                                            public void onCompleted(GraphUser user,
                                                    Response response) {
                                                if (user != null) {

                                                mFbUser = user;

                                                }
                                            }
                                        });
                            }
                        }
                    });
                }
            }

How can i resolve this issue. Please help.

Thanks, Arindam.

Answer 1

I have resolved the issue. Basically i am using the SDK with older version but my FB App in device is latest. So it is giving the issue. Thanks Akhil to point out the version of SDK which helped me to resolve.