Question

When I first created my app, I stored all my runtime custom objects and properties in my app delegate so I could share them across views. I never liked this and always wanted to change it so I did some reading today and moved all my runtime properties and objects to a singleton object like so:

@synthesize gblStr;

+(AppDataSingleton *)singleObj
{
    static AppDataSingleton * single=nil;

    @synchronized(self)
    {
        if(!single)
        {
            single = [[AppDataSingleton alloc] init];
        }  
    }    
    return single;
}

where lets say gblStr can be accessed from any view controller that has the singleton.

This works great and I now have all my objects stored here instead of in my app delegate.

In each view controller I add the property:

AppDataSingleton *globalSingleton; 

and in the viewDidLoad, I instantiate it:

globalSingleton = [AppDataSingleton singleObj];

MY QUESTION IS:
Will there ever be a case where a user will come back to the app and the singleton has been destroyed? Do I need to check for this?

Or, in the case it was destroyed, will it start the app over from scratch?

Answer 1

The singleton will be destroyed, if the app has crashes or stops running. Unless you write your objects to a persistent store (CoreData, .plist, SQLite, etc…), you will have to recreate your objects as well…