I’m currently working on an app that uses a UINavigationController inside UITabBars. The tab bars correspond to both UITableViews as well as a Map View. However, the root view controller of the app is not the parent, or direct parent, of the UITableView custom controllers and map view controller. I also have a p-list that creates NSDictionary objects; it is the datasource that I am using to populate entries in the tables and the map.
So, without a root view controller, how should I create the NSDictionary objects from the data source? It seems to me that the easiest way is to simply recreate the object in each view controller for a view that needs the data. Because I don’t have that many views and the p-list isn’t that long, memory shouldn’t be an issue. However, I do know that this is all very inefficient.
Is there any alternative implementation so that I don’t have to recreate the NSDictionary in each view controller?
This tutorial featuring the singleton guide neatly explains everything:
http://www.cocoanetics.com/2009/05/the-death-of-global-variables/
My only worry now is if multiple view controllers each call the singleton, wouldn’t they all be generating multiple instances of the NSDictionary, and couldn’t that conceivably still take up a lot of memory?
In practical terms, a data model is usually either placed in some kind of a singleton (either your own, or the app delegate which is a kind of singleton).