Ios what is an outlet

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. You can verify this by opening ViewController. This takes you to the public interface of the UIViewController class. As you can see, the view property is declared strong. What happens if a view is added to the view of the view controller? A view always keeps a strong reference to the subviews it manages.

When the view controller is deallocated, the view it manages is deallocated as well. This also means that any subviews the view manages are also deallocated.

Is it? The moment the view controller is deallocated, it releases the label. The label is deallocated if no other objects hold a strong reference to it. What happens if the outlet is declared weak? The object can be a control, such as a button, a slider, and a switch, or it can be any other object defined in your storyboard, such as a label and a progress bar. For example, when your code determines that a label should display some texts, the code sends a message through the outlet telling the label to display the new text.

An action connection is created when you need to send a message from a control in the storyboard to your code. A control is a user interface object that causes actions or visible results when a user manipulates the object.

For example, when a user taps a button, the button sends an action message to your code telling it to execute the appropriate method. Other examples of controls that can be used to create action connections are text fields, sliders, and switches. References: 1. Outlet connection: is to connect a property or instance variable, form the current files owner instance to the xib, when this xib will be deserialized the connection will be made to the files owner object.

Outlet collection: is similar to an outlet, but it connects an array of views to a single outlet var. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. What is the difference between outlet connection and action connection?

Ask Question. Asked 9 years, 4 months ago. Active 4 years, 6 months ago. Viewed 22k times. When I try to create a connection between xib and the file's owner, there are several types to choose from: outlet connection action connection outlet collection connection What are the differences between all of those?

Improve this question. Maverick 75 8 8 bronze badges. An Outlet presents data from your ViewController e. Documentation Archive Developer Search. Retired Document Important: This document may not represent best practices for current development. Prerequisite Articles Nib file Storyboard. Related Articles Target-Action Delegation. Definitive Discussion Outlets.