Android : Combine Activity with Fragment

Learning what I can from the internet and youtube, I'm sure I am not handling this in the appropriate way. I have an existing app which includes a slide out navigation drawer using fragments. I am now trying to get an activity to run within that fragment without any luck. It works when ran on it's own, but after trying to combine the two, I am not able to get "draftactivity" to run properly. The fragment operates as it should.

public class tapsfragment extends Fragment {

public static tapsfragment newInstance() {

    tapsfragment fragment = new tapsfragment();
    return fragment;
}

public tapsfragment(){}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);

    ((MainActivity) activity).onSectionAttached(2);

}

public class DraftActivity extends Activity {

TextView draftfeed;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.draft_activity);

    draftfeed = (TextView) findViewById(R.id.draftfeed);
    new PostAsync().execute();
}

class PostAsync extends AsyncTask<Void, Void, Void> {
    ProgressDialog pd;
    XMLHelper helper;


    @Override
    protected void onPreExecute() {
        pd = ProgressDialog.show(DraftActivity.this, "Taps", "Loading posts for ******.com ...", true, false);
    }

    @Override
    protected Void doInBackground(Void... arg0) {
        helper = new XMLHelper();
        helper.get();
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        StringBuilder builder = new StringBuilder();
        for (ItemValue post : helper.posts) {
            builder.append("\nPost: " + post.getTitle());
            builder.append("\n");
        }
        draftfeed.setText(builder.toString());
        pd.dismiss();
    }

}