java - Why does a TextView from a TableLayout not "update"? -

i have class extends tablelayout, on have textview. correctly displayed first time when constructor called. have method inside class follows:

public class verticalb extends tablelayout   public textview piece1   ...   public verticalb(context con){     super(con);     piece1 = new textview(con){         {             setid(1);             setvisibility(view.visible);             setbackgroundcolor(color.green);         }     };   ...   }    public void painter(double angle, double initangle) {      int finalangle = (int) (angle - initangle);      if(finalangle>0 && finalangle<10){         piece1.setbackgroundcolor(color.green);     }   ... 

i call method class , parameters passed correctly, , if statement entered when corresponds (i have checked), piece1 not coloured (or @ least not showed in screen).

it there way update ui? if not, other alternatives have (maybe override method or asynctask or runonuithread...)

thanks in advance!