OnSharedPreferenceChangeListener not registering change in preference

Question

I'm working on listpreferences and I have implemented the OnSharedPreferenceChangeListener to change the text on a textview based on which item is selected on the listpreference. However it doesn't register any changes and I have run out of ideas so any help would be appreciated. Thanks

public class pref extends PreferenceActivity implements OnSharedPreferenceChangeListener {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.prefs);
    setContentView(R.layout.main);

    TextView text = (TextView) findViewById(R.id.textView1);
    String keys = null;
    SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(this);
    pref.registerOnSharedPreferenceChangeListener(this);


    keys = pref.getString("listPref1", "");
    if (keys == "ON")
    {
        text.setText("ON");
    }
    else if (keys == "OFF")
    {
        text.setText("OFF");
    }
    else{
        text.setText("Choose One");
    }
}

@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
        String key) {
    //What code to I put in here to have the listener register the change
}

}