setAdapter does not work with "extends ActionBarActivity". Within Android Studio.

package uk.co.jackdh.tapchat;

import android.app.AlertDialog;
import android.app.ListActivity;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.HeaderViewListAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;

import com.parse.FindCallback;
import com.parse.Parse;
import com.parse.ParseException;
import com.parse.ParseQuery;
import com.parse.ParseRelation;
import com.parse.ParseUser;
import com.parse.SaveCallback;

import java.util.List;


public class EditContactsActivity extends ActionBarActivity {

    public static final String TAG = EditContactsActivity.class.getSimpleName();

    protected List<ParseUser> mUsers;
    protected ParseRelation<ParseUser> mFriendsRelation;
    protected ParseUser mCurrentUser;

    private ListView mListView;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_edit_contacts);

        getListView().setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
        getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if (getListView().isItemChecked(position)) {
                    //add friend
                    mFriendsRelation.add(mUsers.get(position));
                } else  {
                    //remove friend
                    mFriendsRelation.remove(mUsers.get(position));
                }
                mCurrentUser.saveInBackground(new SaveCallback() {
                    @Override
                    public void done(ParseException e) {
                        if (e == null ) {}
                    }
                });

            }
        });
    }

    protected ListView getListView() {
        if (mListView == null) {
            mListView = (ListView) findViewById(android.R.id.list);
        }
        return mListView;
    }

    protected void setListAdapter(ListAdapter adapter) {
        getListView().setAdapter(adapter);
    }

    protected ListAdapter getListAdapter() {
        ListAdapter adapter = getListView().getAdapter();
        if (adapter instanceof HeaderViewListAdapter) {
            return ((HeaderViewListAdapter)adapter).getWrappedAdapter();
        } else {
            return adapter;
        }
    }

    @Override
    protected void onResume() {
        super.onResume();

        mCurrentUser = ParseUser.getCurrentUser();
        mFriendsRelation = mCurrentUser.getRelation(ParseConstants.KEY_FRIENDS_RELATION);

        ParseQuery<ParseUser> query = ParseUser.getQuery();
        query.orderByAscending(ParseConstants.KEY_USERNAME);
        query.setLimit(1000);
        query.findInBackground(new FindCallback<ParseUser>() {
            @Override
            public void done(List<ParseUser> parseUsers, ParseException e) {
                if (e == null) {
                    //success
                    mUsers = parseUsers;
                    String[] usernames = new String[mUsers.size()];
                    int i = 0;
                    for (ParseUser user : mUsers) {
                        usernames[i] = user.getUsername();
                        i++;

                    }
                    ArrayAdapter<String> adapter = new ArrayAdapter<String>(EditContactsActivity.this, android.R.layout.simple_list_item_checked, usernames);
                    getListView().setAdapter(adapter);

                    addFriendCheckMarks();
                } else {
                    //error
                    Log.e(TAG, e.getMessage());
                    AlertDialog.Builder builder = new AlertDialog.Builder(EditContactsActivity.this);
                    builder.setMessage(e.getMessage())
                            .setTitle(R.string.error_title)
                            .setPositiveButton(android.R.string.ok, null);
                    AlertDialog dialog = builder.create();
                    dialog.show();
                }
            }
        });
    }

    private void addFriendCheckMarks() {
        mFriendsRelation.getQuery().findInBackground( new FindCallback<ParseUser>() {
            @Override
            public void done(List<ParseUser> parseUsers, ParseException e) {
                if (e == null) {
                    //List returned look for match.
                    for (int i = 0; i < mUsers.size(); i++) {
                        ParseUser user = mUsers.get(i);

                        for (ParseUser contact : parseUsers) {
                            if (contact.getObjectId().equals(user.getObjectId())) {
                                getListView().setItemChecked(i, true);

                            }
                        }
                    }
                } else {
                    Log.e(TAG, e.getMessage());
                }
            }
        });
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}