displaypicture.java

final String URL = "http://graph.facebook.com/" + fbID + "/picture?type=large";

// Use a thread because networking operations can't be
// carried out in UI thread.

new Thread(new Runnable() {
    @Override
    public void run() {
        Bitmap bitmap = BitmapFatory.decodeStream(HttpRequest(URL));
        // save bitmap
    }
}).start();


public static InputStream HttpRequest(String strUrl) {
    HttpResponse response = null;
    try {
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet request = new HttpGet();
        request.setURI(new URI(strUrl));
        response = httpClient.execute(request);
        HttpEntity entity = response.getEntity();
        return entity.getContent();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (URISyntaxException e) {
        e.printStackTrace();
    } catch (NullPointerException e) {
        e.printStackTrace();
    }
        return null;
}

SignUpActivity.java

public class SignUpActivity extends Activity {
    private String nameString;
    private String emailString;
    private String fbID;
    // some stuff
    // onCreate, onPause, set layout, create buttons, etc
    
    private void signUpUsingFacebook() {
        Toast.makeText(this, "Connecting to facebook", Toast.LENGTH_LONG).show();
        Session.openActiveSession(this, true, Arrays.asList("email", "user_birthday"), new Session.StatusCallback() {

            @Override
            public void call(Session session, SessionState state,
                    Exception exception) {
                if (session.isOpened()) {
                    Request.newMeRequest(session, new Request.GraphUserCallback() {
                        @Override
                        public void onCompleted(GraphUser user,
                                Response response) {
								
                            if (user == null) {
                                Toast.makeText(SignUpActivity.this, "Unable to connect to Facebook", Toast.LENGTH_SHORT).show();
                                return;
                            }
							
                            nameString = user.getFirstName() + " " + user.getLastName();
                            emailString = (String) user.getProperty("email");
                            fbID = user.getId();
                        }
                    }).executeAsync();
                }
            } 
            
        });
    }
}