FocusDelegate

public abstract void clearFocus()

If the environment supports focus and something is focused, unfocus it.

public abstract void focusItem(@NonNull ItemDetailsLookup.ItemDetails<K> item)

If environment supports focus, focus item.

public abstract int getFocusedPosition()

Returns the position of the currently focused item, or NO_POSITION if nothing is focused.

You must implement this feature if you intend your app to work well with mouse and keyboard. Selection ranges are inferred from focused item when there is no explicit last-selected item.

You can manage and advance focus using keyboard arrows, reflecting this state visibly in the view item. Use can then press shift, then click another item with their mouse to select all items between the focused item and the clicked item.