android - Refreshing TextView in setOnClickListener -

i have textview , button implemented setonclicklistener method. want click on button , update textview, unfortunately happens in first click. can see used view.invalidate(); refresh view, not working. here code:

public class createtarget extends activity {      button   mbutton;      textview board;      @override     public void oncreate(bundle savedinstancestate) {        super.oncreate(savedinstancestate);        setcontentview(r.layout.createtarget);         mbutton   = (button)findviewbyid(r.id.submit);        board     =(textview)findviewbyid(r.id.board);      mbutton.setonclicklistener(new view.onclicklistener() {        public void onclick(view view) {        string s=givetext();   // giving string based on computations        board.settext(s);        view.invalidate();   //refreshing view        }     }); 

first ,the view invalidating button , not textview. second, textview's visibility invisible or gone in first run? third, what's "tsubtarget"?

thanks.