Inherits from: NSObject
Package: com.apple.yellow.foundation
All creation methods are defined in the collection classes such as NSArray and NSDictionary. These methods contain the word "Enumerator," as in NSArray's objectEnumerator method or NSDictionary's keyEnumerator method.
nextElement | Returns the next object in the collection being enumerated. |
nextElement | Returns the next object in the collection being enumerated. |
NSEnumerator is a simple abstract class whose subclasses enumerate
collections of other objects. Collection objects-such as arrays,
sets, and dictionaries-provide special NSEnumerator objects with
which to enumerate their contents. You send nextElement repeatedly to a newly-created
NSEnumerator object to have it return the next object in the original
collection. When the collection is exhausted, null
is
returned. You can't "reset" an enumerator after it's exhausted
its collection. To enumerate a collection again, you need a new
enumerator.
Collection classes such as NSArray, NSSet, and NSDictionary include methods that return an enumerator appropriate to the type of collection. For instance, NSArray has two methods that return an NSEnumerator object: objectEnumerator and reverseObjectEnumerator. NSDictionary also has two methods that return an NSEnumerator object: keyEnumerator and objectEnumerator. These methods let you enumerate the contents of an NSDictionary by key or by value, respectively.
It isn't safe to modify a mutable collection while enumerating through it. |