I want to Refresh a ListView in a Fragment when a Dialog is closed. Until now the refresh only works when I restart the app and I don't really know why.
Here are the classes:
This is the Fragment with the ListView on it, that i want to refresh, when the Dialog is closed.
public class RegisterListFragment extends Fragment {
    public static final String TAG = "RegisterListFragment";
    RegisterListAdapter adapter;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        setRetainInstance(true);
        // TODO Auto-generated method stub
        View view = inflater.inflate(R.layout.act_select_list_fragment, container, false);
        ListView list = (ListView) view.findViewById(R.id.register_list);
        list.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                                    long arg3) {
                Intent i = new Intent(getActivity(), com.example.smartkasse.Act_Register.MainActivity.class).addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                TextView selectedRegisterTextView = (TextView) arg1.findViewById(R.id.title);
                String selectedRegisterName = (String) selectedRegisterTextView.getText();
                i.putExtra("selectedRegisterName", selectedRegisterName);
                startActivity(i);
                getActivity().finish();
            }
        });
        adapter = new RegisterListAdapter(getActivity());
        list.setAdapter(adapter);
        return view;
    }
    public void refreshData() {
        adapter.notifyDataSetChanged();
    }
}
And this is the Adapter I fill the List with:
public class RegisterListAdapter extends BaseAdapter {
    View view = null;
    Database db = new Database(mContext);
    data=db.getAlltitles();
    if(convertView==null)
    {
        view = (View) inflater.inflate(R.layout.act__select_listview, null);
        TextView title = (TextView) view.findViewById(R.id.title);
        TextView artist = (TextView) view.findViewById(R.id.artist);
        TextView duration = (TextView) view.findViewById(R.id.duration);
        ImageView thumb_image = (ImageView) view.findViewById(R.id.list_image);
        title.setText(data.get(position));
        //artist.setText(data.get(position));
        //duration.setText(data.get(position));
        //thumb_image.setImageResource(R.drawable.ic_launcher);
        return view;
    }
    else
    {
        TextView title = (TextView) convertView.findViewById(R.id.title);
        TextView artist = (TextView) convertView.findViewById(R.id.artist);
        TextView duration = (TextView) convertView.findViewById(R.id.duration);
        ImageView thumb_image = (ImageView) convertView.findViewById(R.id.list_image);
        title.setText(data.get(position));
        // artist.setText(data.get(position));
        // duration.setText(data.get(position));
        //thumb_image.setImageResource(R.drawable.ic_launcher);
        return convertView;
    }
}
And this is the Main that holds everything together:
When the positv Button of the Dialog is pressed, then new Data is added to the Database that i want
public class MainActivity extends SherlockFragmentActivity implements OnRegisterCreatedListener {
    RegisterListFragment registerListFragment;
    HelpFragment helpFragment;
    boolean helpVisible = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Grund-Layout für die Activity festlegen
        setContentView(R.layout.act_select_main);
        addFragments();
        supportInvalidateOptionsMenu();
        setLargeInLandscape();
    }
// Was passiert wenn der Menüknopf gedrückt wird
    // Inflate the menu; this adds items to the action bar if it is present.
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Zeigt nur die die nicht in Actionbar sind, kann aber eingestellt
        // werden im XML-File
        if (helpVisible) {
            getSupportMenuInflater().inflate(
                    R.menu.act_select_menu_help_visible, menu);
        } else {
            getSupportMenuInflater().inflate(
                    R.menu.act_select_menu_registerlist_visible, menu);
        }
        return true;
    }
    // Was passiert wenn ein Menüpunkt ausgewählt wird
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle item selection
        switch (item.getItemId()) {
            // Das wenn der Knopf das Plus war
            case R.id.menu_help:
                changeFragment();
                // this.supportInvalidateOptionsMenu();
                break;
            case android.R.id.home:
                changeFragment();
                // this.supportInvalidateOptionsMenu();
                break;
            case R.id.menu_add_register:
                FragmentManager fm = getSupportFragmentManager();
                NewRegisterFragment dialog = new NewRegisterFragment();
                dialog.setRetainInstance(true);
                dialog.show(fm, "fragment_name");
                break;
            // Listenelement hinzufügen und dem Adapter sagen es hat sich was
            // geändert, mach neu
        }
        return true;
    }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // TODO Auto-generated method stub
        switch (keyCode) {
            case KeyEvent.KEYCODE_BACK:
                if (helpVisible = true) {
                    // changeFragment();
                    helpVisible = false;
                    getSupportActionBar().setDisplayHomeAsUpEnabled(false);
                    supportInvalidateOptionsMenu();
                }
                break;
        }
        return super.onKeyDown(keyCode, event);
    }
    private void addFragments() {
        // Zuerst versuchen Fragmente aus dem Layout zu laden
        registerListFragment = (RegisterListFragment) getSupportFragmentManager()
                .findFragmentById(R.id.registerListFragment);
        helpFragment = (HelpFragment) getSupportFragmentManager()
                .findFragmentById(R.id.HelpFragment);
        // Wenn die Fragmente nicht im Layout sind, füge sie dynamisch hinzu
        if (registerListFragment == null && helpFragment == null) {
            FragmentTransaction ft = getSupportFragmentManager()
                    .beginTransaction();
            registerListFragment = new RegisterListFragment();
            helpFragment = new HelpFragment();
            ft.setCustomAnimations(android.R.anim.fade_in,
                    android.R.anim.fade_out, android.R.anim.fade_in,
                    android.R.anim.fade_out);
            ft.add(R.id.Fragmentframe, registerListFragment);
            ft.add(R.id.Fragmentframe, helpFragment);
            ft.show(registerListFragment);
            ft.hide(helpFragment);
            ft.commit();
            // OnclickListener für Fragmentwechseln
        }
    }
    private void changeFragment() {
        // Fragmente austauschen
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();
        if (registerListFragment.isVisible()) {
            ft.hide(registerListFragment);
            ft.show(helpFragment);
            helpVisible = true;
            supportInvalidateOptionsMenu();
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            if (getSupportFragmentManager().findFragmentByTag(
                    "RegisterListFragment") == null) {
                ft.addToBackStack("RegisterListFragment");
            }
        } else {
            ft.hide(helpFragment);
            helpVisible = false;
            supportInvalidateOptionsMenu();
            getSupportActionBar().setDisplayHomeAsUpEnabled(false);
            fm.popBackStack();
        }
        ft.commit();
    }
    private void setLargeInLandscape() {
        if ((getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) == Configuration.SCREENLAYOUT_SIZE_LARGE) {
            setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
            findViewById(R.id.menu_help).setVisibility(View.GONE);
        }
        if ((getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) == Configuration.SCREENLAYOUT_SIZE_XLARGE) {
            setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
            findViewById(R.id.menu_help).setVisibility(View.GONE);
        }
    }
    @Override
    public void OnRegisterCreated() {
        // TODO Auto-generated method stub
        registerListFragment.refreshData();
    }
to see in the listView "behind" the dialog. I tried so much, but i really didnt get it. Hope you can help me.
Thanks :)