ทำ Manager กว้างคงที่

      HorizontalFieldManager manager = new HorizontalFieldManager()
     {
         //define width
         public int getPreferredWidth()
         {
             return Display.getWidth();
         }
         //define height
         public int getPreferredHeight()
         {
             return 100;
         }
         protected void sublayout( int maxWidth, int maxHeight )
         {
             super.sublayout(getPreferredWidth(),
                             getPreferredHeight());
             setExtent(getPreferredWidth(), getPreferredHeight());
         }
     };

---

 public int getPreferredWidth() {
  return getScreen().getWidth();
 }

 protected void sublayout( int maxWidth, int maxHeight ) {
  super.sublayout(getPreferredWidth(),
    maxHeight);
  XYRect rec = getExtent();
  setExtent(getPreferredWidth(), rec.height);
 }