Facebook Android SDK 3.0 - opening a session

I've been working with the new Facebook Android SDK (version 3.0) the past two weeks and every time I thought "yes, now I've got it!", I've found something wrong with the integration of it in my apps! But this time I think I've really got it (!!) and I'm gonna do a sequence of three Blog posts to explain (1) how to connect to a Facebook user account and open a Facebook session, (2) how to obtain additional, required Facebook permissions and then perform a Facebook API request like posting to the user's feed, and (3) how to log out and close the Facebook session. I wish the official documentation better explained these core concepts but it doesn't! And this is evident in browsing developer forums like Stack Overflow where almost everybody has a different take on how to perform the above operations!! So here's my two cents...

Firstly, I like to a have single Activity (let's call it BaseFacebookActivity) that has all my Facebook methods in it and which Activities that do Facebook operations are to extend. Don't forget the onActivityResult(...) method!, as follows:

public abstract class BaseFacebookActivity
  extends Activity
{
  @Override
  protected void onActivityResult(
      int requestCode,
      int resultCode,
      Intent data)
  {
    super.onActivityResult(requestCode, resultCode, data);

    if (Session.getActiveSession() != null)
      Session.getActiveSession().onActivityResult(
          this,
          requestCode,
          resultCode,
          data);
  }

  // other methods to follow
}

Secondly, let's define an interface which will help us report back to the user when an attempt to open a Facebook session has been successful or not, as follows:

public interface FacebookConnectHandler
{
  /** Method to call when the user's Facebook account
    * was connected to
    * and a Facebook session was opened successfully.*/
  public void onSuccess();
  /** Method to call when the user's Facebook account
    * was not connected to
    * or a Facebook session was not opened successfully.*/
  public void onFailure();
}

Thirdly and finally, a method to put in your BaseFacebookActivity which will connect to the user's Facebook account and open a Facebook session, as follows:

private void connectFacebookAccount(
    final FacebookConnectHandler handler)
{
  // safety check
  if (!isActiveNetworkConnected())
  {
    handler.onFailure();
    return;
  }

  // check whether the user already has an active session
  // and try opening it if we do

  // (note: making a Session.openActiveSessionFromCache(...) call
  // instead of simply checking whether the active session is opened
  // because of a bug in the Facebook sdk
  // where successive calls to update a token
  // (requesting additional permissions etc)
  // don't result in a session callback)

  if (Session.getActiveSession() != null
      && Session.openActiveSessionFromCache(this) != null)
  {
    handler.onSuccess();
    return;
  }

  // initialise the session status callback

  Session.StatusCallback callback = new Session.StatusCallback()
  {
    @Override
    public void call(
        Session session,
        SessionState state,
        Exception exception)
    {
      // safety check
      if (isFinishing())
        return;

      // check session state

      if (state.equals(SessionState.CLOSED)
          || state.equals(SessionState.CLOSED_LOGIN_FAILED))
      {
        clearFacebookInfoFromSharedPreferences();

        // specific action for when the session is closed
        // because an open-session request failed
        if (state.equals(SessionState.CLOSED_LOGIN_FAILED))
        {
          cancelProgressDialog();
          handler.onFailure();
        }
      }
      else if (state.equals(SessionState.OPENED))
      {
        cancelProgressDialog();

        saveFacebookInfoInSharedPreferences(
            session.getAccessToken(),
            session.getExpirationDate());

        showToast("Succeeded connecting to Facebook");

        handler.onSuccess();
      }
    }
  };

  // make the call to open the session

  showProgressDialog("Connecting to Facebook...");

  if (Session.getActiveSession() == null
      && getSharedPreferences().contains("facebookAccessToken")
      && getSharedPreferences().contains("facebookAccessTokenExpires"))
  {
    // open a session from the access token info
    // saved in the app's shared preferences

    String accessTokenString = getSharedPreferences().getString(
        "facebookAccessToken",
        "");

    Date accessTokenExpires = new Date(getSharedPreferences().getLong(
        "facebookAccessTokenExpires",
        0));

    AccessToken accessToken = AccessToken.createFromExistingAccessToken(
        accessTokenString,
        accessTokenExpires,
        null,
        null,
        null);

    Session.openActiveSessionWithAccessToken(this, accessToken, callback);
  }
  else
    // open a new session, logging in if necessary
    Session.openActiveSession(this, true, callback);
}

Done! In the next Blog post I'll show how to use this connectFacebookAccount(...) method prior to making a Facebook API request like posting to the user's feed.