volume raise indication dialog in blackberry

In my app I want to display an dialog(a screen indicating volume level) when user press VOLUME_UP and VolUme_down keys in the Blackberry Phone,Now I increase or decrase volume when user clicks those keys:

public boolean keyDown(int keycode, int time) { if(volume != null){ int key = Keypad.key(keycode); if(key == Keypad.KEY_VOLUME_DOWN){ volume.setLevel(volume.getLevel()-10); } else if(key == Keypad.KEY_VOLUME_UP){ volume.setLevel(volume.getLevel()+10); }

        }
        return false;
    }

I need dialog which like in Blackberry phone when users take songs(a开发者_运维百科nd press volume keys) in blackberry Media folder. If any one have idea please help,Thanks.