SharedPreference default value from PreferenceManager with working OnSharedPreferenceChangeListener

Question

I wanted to make a option class, where you could load all preferences of a user. If there is no keys in the sharedPreference then I would like to load the xml defaults in Preference.

The problem is, that I can't get a class working with also an PreferenceActivity with implements OnSharedPreferenceChangeListener. And I can't get those keys loaded. So how do other applications do this? The commeted code with PreferenceManager did I also tried, but no luck there :(

Some code for the class options

static SharedPreferences GetSharedPreferences(Context context){


        return context.getSharedPreferences("Name", Context.MODE_PRIVATE);

}

public static void ClearSharedPreferences(Context context){
    GetSharedPreferences(context).edit().clear().apply();
}

public static void SaveTextSize(Context context, int size){
    SharedPreferences sharedPreferences = GetSharedPreferences(context);

    if (textSizeKey == null)
        textSizeKey = context.getString(R.string.textSizeKey);

    sharedPreferences.edit().putInt(textSizeKey, size).commit();

    Log.v("Saving", "Text size save: " + size);
}

public static int LoadTextSize(Context context) {
    SharedPreferences sharedPreferences = GetSharedPreferences(context);

    if (textSizeKey == null)
        textSizeKey = context.getString(R.string.textSizeKey);

    if (!sharedPreferences.contains(textSizeKey))
        Log.i("Load", "Key: " + textSizeKey + " not found");

    return sharedPreferences.getInt(textSizeKey, 16);
}

Code for the Preference activity

public class SettingsActivity extends PreferenceActivity implements
    OnSharedPreferenceChangeListener {
private CheckBoxPreference mCheckBoxPreference;
private ListPreference mListPreference;

private static String updateCheckBoxName;
private static String updateListName;
private SharedPreferences sharedPreferences;

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

    addPreferencesFromResource(R.xml.preferences);

        updateCheckBoxName = getString(R.string.options_main);
        updateListName = getString(R.string.options_toggle);

        //PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
    //sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
         sharedPreferences = Options.GetSharedPreferences(this);


    mCheckBoxPreference = (CheckBoxPreference) findPreference(updateCheckBoxName);
    mListPreference = (ListPreference) findPreference(updateListName);

}

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

    // Set up a listener whenever a key changes
     sharedPreferences.registerOnSharedPreferenceChangeListener(this);
}

private void updateScreen() {
    mCheckBoxPreference.setSummary(sharedPreferences.getBoolean(
            updateCheckBoxName, false) ? "Will automatic update"
            : "No automatic update");
    mListPreference.setSummary(mListPreference.getEntry());
}

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

     sharedPreferences.unregisterOnSharedPreferenceChangeListener(this);
}

@Override
public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
        Preference preference) {
    // Hack for dialog
    if (preference.equals(getString(R.string.textSizeKey))){
        TextSizeAlert textSizeAlert = new TextSizeAlert(SettingsActivity.this) {

            @Override
            public void SizeCallback(int size) {
                Options.SaveTextSize(getApplicationContext(), size);
            }

        };          
        textSizeAlert.ShowTextDialog();
        return true;
    }

    return super.onPreferenceTreeClick(preferenceScreen, preference);
}

public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
        String key) {
     updateScreen();
}

}

Main Activity:

public void SomeMethod() {
     int updateTime = Options.LoadUpdateTime(this);
     //do something with it
}