onResume isn't properly executed when returning from Settings

Question

In my app, when there's no WiFi connection, I turn the WiFi connection on with an AlertDialog and I call the WiFi Settings screen. When I hit the back button, I assume that it goes in the onResume() method of the MainActivity. In this method, I call a loadTweets method, which reloads my tweets. This works when I hop from one activity to another.

When I hit back in the WiFi Settings Screen, the debugger goes in the onResume method, loops through the loadTweets method, but it doesn't show the reloaded tweets.

Am I missing a step here?

onResume() method:

public void onResume(){
    super.onResume();
    checkWifi();   
    loadTweets();
}

LoadTweets method:

private ArrayList<Tweets> loadTweets(){
ArrayList<Tweets> tweets = new ArrayList<Tweets>();
try {
        HttpClient hc = new DefaultHttpClient();
        HttpGet get = new
        HttpGet("http://search.twitter.com/search.json?q=JobXXL_be&rpp=5");
        HttpResponse rp = hc.execute(get);
        if(rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK)
        {
                String result = EntityUtils.toString(rp.getEntity());
                JSONObject root = new JSONObject(result);
                JSONArray sessions = root.getJSONArray("results");
                for (int i = 0; i < sessions.length(); i++) {
                        JSONObject session = sessions.getJSONObject(i);
                        Tweets tweet = new Tweets();
                        tweet.setTweet(session.getString("text"));
                        tweet.setUser(session.getString("from_user"));
                        tweet.setDate(session.getString("created_at").substring(5,16));
                        tweets.add(tweet);
                }
        }
} catch (Exception e) {
        Log.e("TwitterFeedActivity", "Error loading JSON", e);
 }
 return tweets;
}

TweetListAdapter class:

private class TweetListAdaptor extends ArrayAdapter<Tweets> {
                private ArrayList<Tweets> tweets;
                public TweetListAdaptor(Context context, int textViewResourceId, ArrayList<Tweets> tweets) {
                         super(context, textViewResourceId, tweets);
                         this.tweets = loadTweets();
                }
                @Override
                public View getView(int position, View convertView, ViewGroup parent) {
                        View v = convertView;
                        if (v == null) {
                                LayoutInflater vi = (LayoutInflater) getSystemService (Context.LAYOUT_INFLATER_SERVICE);
                                v = vi.inflate(R.layout.tweetitem, null);
                        }
                        Tweets o = tweets.get(position);
                        TextView tt = (TextView) v.findViewById(R.id.TWEET_TEXT);
                        TextView bt = (TextView) v.findViewById(R.id.TWEET_SCREEN_NAME);
                        TextView date = (TextView) v.findViewById(R.id.TWEET_CREATED_AT);
                        tt.setText(o.getTweet());
                        bt.setText(o.getUser());
                        date.setText(o.getDate());
                        return v;
                }

                public void setTweets(ArrayList<Tweets> tweet){
                    this.tweets = tweet;
                }
            }