Coming from a Java background I am used to dealing with actions though I'm not really sure why the method requires a boolean is returned and don't fully understand the explanation given on the site: true if the callback consumed the long click, false otherwise.
As you may know, the View hierarchy in Android is represented by a tree. When you return true from the onItemLongClick() - it means that the View that currently received the event is the true event receiver and the event should not be propagated to the other Views in the tree; when you return false - you let the event be passed to the other Views that may consume it. Hope this helps.