package net.somethingdreadful.MAL;

import android.app.ActionBar;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;

public class Settings extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setTitle(R.string.title_activity_settings);

        ActionBar actionBar = getActionBar();
        if (actionBar != null)
            actionBar.setDisplayHomeAsUpEnabled(true);

        NfcHelper.disableBeam(this);

        getFragmentManager().beginTransaction()
                .replace(android.R.id.content, new SettingsFragment())
                .commit();
    }
}

package net.somethingdreadful.MAL;

import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.MenuItem;

public class Settings extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setTitle(R.string.title_activity_settings);

        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null)
            actionBar.setDisplayHomeAsUpEnabled(true);

        NfcHelper.disableBeam(this);

        getFragmentManager().beginTransaction()
                .replace(android.R.id.content, new SettingsFragment())
                .commit();
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                finish();
                break;
        }
        return true;
    }
}

Add home button in the actionbar (Settings)