How to use

getRequired

method

in

com.badlogic.gdx.scenes.scene2d.utils.ArraySelection

/** Sets the selection to only the passed item, if it is a possible choice.
 * @param item May be null. */
public void setSelected (T item) {
  if (items.contains(item, false))
    selection.set(item);
  else if (selection.getRequired() && items.size > 0)
    selection.set(items.first());
  else
    selection.clear();
}

/** Sets the selection to only the passed item, if it is a possible choice.
 * @param item May be null. */
public void setSelected (T item) {
  if (items.contains(item, false))
    selection.set(item);
  else if (selection.getRequired() && items.size > 0)
    selection.set(items.first());
  else
    selection.clear();
}

/** Sets the selection to only the passed item, if it is a possible choice.
 * @param item May be null. */
public void setSelected (T item) {
  if (items.contains(item, false))
    selection.set(item);
  else if (selection.getRequired() && items.size > 0)
    selection.set(items.first());
  else
    selection.clear();
}

/**
 * Sets the current items, clearing the selection if it is no longer valid.
 * If a selection is {@link ArraySelection#getRequired()}, the first item is
 * selected.
 */
public void setItems(Array<T> newItems) {
  if (newItems == null)
    throw new IllegalArgumentException("newItems cannot be null.");
  items.clear();
  items.addAll(newItems);
  T selected = getSelected();
  if (!items.contains(selected, false)) {
    if (selection.getRequired() && items.size > 0)
      selection.set(items.first());
    else
      selection.clear();
  }
  invalidateHierarchy();
}