Используйте этот пример / пример:
String choices[] = {"0","1","2","3","4"};
ObjectChoiceField choice1 = new ObjectChoiceField("", choices, ""){
public void layout(int width, int height){
width = 80;
super.layout(getWidth(), getHeight());
super.layout(width, height);
setExtent(width, super.getHeight());
}
};