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kasaltrix
9,491 PointsWhat does a single instance of UIApplication represent in this video?
As explained in the documentation of UIApplication class, "Every app must have exactly one instance of UIApplication (or a subclass of UIApplication)".
Does it mean that I can't declare a UIApplication object anywhere else in the app after declaring it once in my table view controller class? If so, what is the reason?
1 Answer
Madhav Sharma
4,081 PointsWhen you declare '''UIAppliation *testApp = [UIApplication sharedApplication]''' you are not declaring a UIApplication, but you are declaring a pointer. It is the exact same thing if you just typed '''id''' but that's not good practice when it isn't needed.
The pointer just hold the address of the where your UIApplication instance is saved.
Rememeber: if you have an Asterix in the declaration it is a pointer to the memory address, not the actual instance. >> So I declare two pointers that point to the same address and if I change the properties of an object using one of those pointers, it will be reflected in the dereferencing of the other one as well.
kasaltrix
9,491 Pointskasaltrix
9,491 PointsThanks for your reply Madhav. I was wondering if you could help me differentiate between an object and an instance by giving an ObjectiveC code example as it would turn out to be really helpful. Thanks in advance :)