IBOutlet and IBAction

user_119570 0
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What is the purpose of using IBOutlets and IBActions in Xcode and Interface Builder?

Does it make any difference if I don't use IBOutlets and IBActions?

Swift:

@IBOutlet weak var textField: UITextField!

@IBAction func buttonPressed(_ sender: Any) { /* ... */ }

Objective-C:

@property (nonatomic, weak) IBOutlet UITextField *textField;

- (IBAction)buttonPressed:(id)sender { /* ... */ }
ibaction iboutlet swift objective-c interface-builder
11 Answers

The traditional way to flag a method so that it will appear in Interface Builder, and you can drag a connection to it, has been to make the method return type IBAction. However, if you make your method void, instead (IBAction is #define'd to be void), and provide an (id) argument, the method is still visible. This provides extra flexibility, al

All 3 of these are visible from Interface Builder:

-(void) someMethod1:(id) sender; 
-(IBAction) someMethod2; 
-(IBAction) someMethod3:(id) sender;

See Apple's Interface Builder User Guide for details, particularly the section entitled Xcode Integration.

user_5040680

One of the top comments on this Question specifically asks:

All the answers mention the same type of idea.. but nobody explains why Interface Builder seems to work just the same if you DO NOT include IBAction/IBOutlet in your source. Is there another reason for IBAction and IBOutlet or is it ok to leave them off?

This question is answered well by NSHipster:

IBAction

https://nshipster.com/ibaction-iboutlet-iboutletcollection/#ibaction

As early as 2004 (and perhaps earlier), IBAction was no longer necessary for a method to be noticed by Interface Builder. Any method with the signature -(void){name}:(id)sender would be visible in the outlets pane.

Nevertheless, many developers find it useful to still use the IBAction return type in method declarations to denote that a particular method is connected to by an action. Even projects not using Storyboards / XIBs may choose to employ IBAction to call out target / action methods.

IBOutlet:

https://nshipster.com/ibaction-iboutlet-iboutletcollection/#iboutlet

Unlike IBAction, IBOutlet is still required for hooking up properties in code with objects in a Storyboard or XIB.

An IBOutlet connection is usually established between a view or control and its managing view controller (this is often done in addition to any IBActions that a view controller might be targeted to perform by a responder). However, an IBOutlet can also be used to expose a top-level property, like another controller or a property that could then be accessed by a referencing view controller.

user_12653930

IBOutlet

  • It is a property.
  • When the nib(IB) file is loaded, it becomes part of encapsulated data which connects to an instance variable.
  • Each connection is unarchived and reestablished.

IBAction

  • Attribute indicates that the method is an action that you can connect to from your storyboard in Interface Builder.

@ - Dynamic pattern IB - Interface Builder

user_43800360

I didn't know you didn't need them anymore, they used to be to make it possible for interface builder to find them in your source, in swift I would image that IBAction is still needed, because it needed to change how your method can be called from interface builder though I imaging @objc would do the same thing. I personal intend to still keep using them because it documents what the method or interface is suppose to do.

user_8153710
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