How to check if FaceBook user is logged in or logged out in Android App

Question

I have this code from the Facebook Developers site. What it does is simply allow the user to log in and log out. What I want to do now is check whether they are logged in or out in another activity. So, they log in, go to a new activity, and in that new activity, I want to see if they are logged in. If so, I'll display their profile picture and name. So what I need to know is:

1. How to check if they are logged in or logged out
2. How can I check this in an activity where the session wasn't started.

Thanks!

public class MainActivity extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  // start Facebook Login
  Session.openActiveSession(this, true, new Session.StatusCallback() {

  // callback when session changes state
  @Override
  public void call(Session session, SessionState state, Exception exception) {
    if (session.isOpened()) {

      // make request to the /me API
      Request.newMeRequest(session, new Request.GraphUserCallback() {

        // callback after Graph API response with user object
        @Override
        public void onCompleted(GraphUser user, Response response) {
          if (user != null) {
            TextView welcome = (TextView) findViewById(R.id.welcome);
            welcome.setText("Hello " + user.getName() + "!");
          }
        }
      }).executeAsync();
    }
  }
});
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  Session.getActiveSession().onActivityResult(this, requestCode, resultCode, data);
}

}

Answer 1

I highly suggest you to take a look at https://github.com/sromku/android-simple-facebook for Facebook on Android. All the session part will be handled directly by the library.

Answer 2

Try this, I can not grant that it is correct, but I've used in my projects.

    //do logout
    public static void logout() {
        Session session = Session.getActiveSession();
        if (session != null && !session.isClosed()) {
            session.closeAndClearTokenInformation();
        }
    }

    //check whether login/out.
    public static boolean isLoggedIn() {
        Session session = Session.getActiveSession();
        return (session != null && session.getAccessToken() != null && session.getAccessToken().length() > 1);
    }

    //In your create you might do this
    ......
    Session session = Session.getActiveSession();
    if (session == null) {
        if (_savedInstanceState != null) {
            session = Session.restoreSession(this, null,
                    _statusCallback, _savedInstanceState);
        }
        if (session == null) {
            session = new Session(this);
        }
        Session.setActiveSession(session);
        if (session.getState().equals(SessionState.CREATED_TOKEN_LOADED)) {
            session.openForRead(new Session.OpenRequest(_fragment)
                    .setCallback(_statusCallback));
        }
    }
    .....