An application typically sets outlet connections between its custom controller objects and objects on the user interface, but they can be made between any objects that can be represented as instances in Interface Builder, even between two custom objects.
As with any item of object state, you should be able to justify its inclusion in a class; the more outlets an object has, the more memory it takes up. If there are other ways to obtain a reference to an object, such as finding it through its index position in a matrix, or through its inclusion as a function parameter, or through use of a tag an assigned numeric identifier , you should do that instead.
Outlets are a form of object composition, which is a dynamic pattern that requires an object to somehow acquire references to its constituent objects so that it can send messages to them. It typically holds these other objects as properties backed by instance variables.
These variables must be initialized with the appropriate references at some point during the execution of the program. All Rights Reserved. How IBAction is different than a normal method of Swift? An Outlet is simply a way to reference part of your UI. For example if you needed to change a button color or the text of a label you would need to set up an outlet for it to find it in the code.
An action on the other hand tells the UI what function to call. Should IBOutlets be strong or weak? The official answer from Apple is that IBOutlets should be strong. The only case when an IBOutlet should be weak is to avoid a retain cycle. A strong reference cycle can result in memory leaks and app crashes. What is a weak VAR in Swift? A weak reference is just a pointer to an object that doesn't protect the object from being deallocated by ARC.
In Swift, all weak references are non-constant Optionals think var vs. As you can see, the outlet is declared strong. What would change if you declared the outlet weak? You can give it a try and run the application. If there seemingly is no difference in behavior, then why is this important?
Why are some developers declaring outlets strong while others define them weak? To understand why outlets can be declared strong or weak, you need to be aware which objects keep a reference to which objects. Reference counting. Every view controller keeps a reference to the view it manages. That reference is strong. The view should not be deallocated as long as the view controller is alive.
That makes sense. Prerequisite Articles Nib file Storyboard. Related Articles Target-Action Delegation. Definitive Discussion Outlets.
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