Facebook Android SDK 3.0 - how to log out and close a session

In the previous two Blog posts (here and here), I showed how to connect a user to their Facebook account (i.e. open a Facebook session) and how to make a Facebook API request (requesting additional Facebook permissions en route if necessary). In this final Blog post, I'll show to close the Facebook session, as follows:

public void disconnectFacebookAccount()
{
  showProgressDialog("Disconnecting Facebook account...");

  new AsyncTask<Void, Void, Boolean>()
  {
    @Override
    protected Boolean doInBackground(Void... params)
    {
      if (Session.getActiveSession() != null)
        Session.getActiveSession().closeAndClearTokenInformation();

      clearFacebookInfoFromSharedPreferences();

      // perform any other operations you need to do perform here
      // such as clearing local database tables and so forth

      return true;
    }

    @Override
    protected void onPostExecute(Boolean result)
    {
      // safety check
      if (isFinishing())
        return;

      if (result == null
          || result == false)
        onFailedFacebookDisconnect();
      else
        onSucceededFacebookDisconnect();
    }
  }.execute();
}

That's it! That's the end of my Facebook Android 3.0 series. You should have enough know-how now for all kinds of Facebook API requests! :)

Facebook Android SDK 3.0 - requesting additional permissions and making an API request

At the end of the previous Blog post, I defined a connectFacebookAccount(...) method which connects to a user's Facebook account and opens a Facebook session for subsequent Facebook API requests. In this Blog post, I'll show how to use this method and the opened Facebook session to post to the user's feed. You'll notice in reading through the postFacebookMessage(...) method below that it is sometimes necessary to request additional Facebook permissions before making a Facebook API request. (It's no longer possible to request all required Facebook permissions at the point of first connecting to Facebook.) Without further ado, here's the postFacebookMessage(...) method:

/** Posts the provided message to Facebook,
 * connecting to Facebook
 * and requesting required permissions en route if necessary.*/
public void postFacebookMessage(final String message)
{
  connectFacebookAccount(new FacebookConnectHandler()
  {
    @Override
    public void onSuccess()
    {
      // safety check
      if (isFinishing())
        return;

      showProgressDialog("Posting message to Facebook...");

      // check for publish permissions

      final List permissions_required = Arrays.asList(
          new String[] { Constants.Facebook_Permission_PublishStream });

      if (Session.getActiveSession().getPermissions() == null
          || !Session.getActiveSession().getPermissions().containsAll(
              permissions_required))
      {
        // need to make a Session.openActiveSessionFromCache(...) call
        // because of a bug in the Facebook sdk
        // where a second call to get permissions
        // won't result in a session callback when the token is updated

        if (Session.openActiveSessionFromCache(BaseFacebookActivity.this) == null)
        {
          onFailedPostingFacebookMessage();
          return;
        }

        Session.getActiveSession().addCallback(new Session.StatusCallback()
        {
          @Override
          public void call(
              Session session,
              SessionState state,
              Exception exception)
          {
            if (exception != null
                || state.equals(SessionState.CLOSED)
                || state.equals(SessionState.CLOSED_LOGIN_FAILED))
            {
              // didn't get required permissions

              session.removeCallback(this);

              // safety check
              if (!isFinishing())
                onFailedPostingFacebookMessage();
            }
            else if (state.equals(SessionState.OPENED_TOKEN_UPDATED)
                && session.getPermissions().containsAll(permissions_required))
            {
              // got required permissions

              session.removeCallback(this);

              // safety check
              if (!isFinishing())
                postFacebookMessage(message);
            }
          }
        });

        Session.getActiveSession().requestNewPublishPermissions(
            new Session.NewPermissionsRequest(
                BaseFacebookActivity.this,
                permissions_required));

        return;
      }

      // got sufficient permissions, so publish message

      Bundle bundle_params = new Bundle();

      bundle_params.putString("caption", "Enter your caption here"));
      bundle_params.putString("description", "Enter your description here");
      bundle_params.putString("link", "http://www.your-app-url.com");
      bundle_params.putString("message", message);
      bundle_params.putString("name", "My App for Android");
      bundle_params.putString("picture", "http://www.your-app-icon-url.com");

      new Request(
          Session.getActiveSession(),
          "me/feed",
          bundle_params,
          HttpMethod.POST,
          new Request.Callback()
          {
            @Override
            public void onCompleted(Response response)
            {
              // safety check
              if (isFinishing())
                return;

              if (response.getError() != null
                  || response.getGraphObject() == null)
              {
                onFailedPostingFacebookMessage();
                return;
              }

              Object id = response.getGraphObject().getProperty("id");

              if (id == null
                  || !(id instanceof String)
                  || TextUtils.isEmpty((String)id))
                onFailedPostingFacebookMessage();
              else
                onSucceedPostingFacebookMessage((String)id);
            }
          }).executeAsync();
    }

    @Override
    public void onFailure()
    {
      cancelProgressDialog();
      showToast("Failed connecting to Facebook.");
    }
  });
}

You'll notice two methods above onSucceedPostingFacebookMessage(...) and onFailedPostingFacebookMessage() which you'll need to define to cancel the shown progress dialog, show a toast alerting the user to success or failure, and to perform any additional operations you require. That's it! Just one last Blog post to follow...

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.

Windows 8 - how to stop Thumbs.db files being created

I've just recently upgraded from Windows 7 to Windows 8 and I've started seeing Thumbs.db files appear in my folders which contain images. This has adverse effects as you can imagine when running scripts etc that expect only images. So, it's important my operating system not add files in my folders without my say-so!

The only way I've found so far of stopping the operating system adding this Thumbs.db file in my folders is as follows:

• open a File Explorer window,
• select the View tab from within the File Explorer window,
• open the Folder Options window by clicking the Options button from within the View tab,
• select the View tab from within the Folder Options window,
• lastly, tick the Always show icons, never thumbnails option in the Advanced settings section of the View tab.

That's it. Hopefully no more Thumbs.db files will be created in your folders as long as this option is ticked. Bear in mind however that you might have to delete any existing Thumbs.db files.