Скачать или смотреть How to Properly Use addTarget in Swift for Buttons in MVC Pattern

Learn how to connect UIButton actions in a UIView subclass to methods in your ViewControllers in Swift. Follow this guide for an MVC-compliant solution!
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Swift UIButton Target Handling Across MVC Components

When developing applications in Swift, particularly using the Model-View-Controller (MVC) design pattern, you often need to connect actions from UI components to functional methods in your view controllers. This can sometimes get tricky, especially when you’re managing your UI within separate UIView files. In this post, we’ll cover how to effectively set up a button in a UIView to trigger a function in a ViewController.

The Scenario

You have a ViewController named MyViewController, where you’ve added a custom UIView called MyView. Within MyView, you've created a button, and you want this button to trigger a function in MyViewController when pressed. However, you're facing a challenge with how to correctly set the target for the button since it's located in a different class.

Understanding the Problem

You may have attempted to set the target for the button with:

[[See Video to Reveal this Text or Code Snippet]]

However, this will not work because you cannot pass the class name (MyViewController) directly as the target. Rather, you need to pass an instance of the view controller.

Solutions to Achieve Button Functionality

There are two main approaches to connect your button's action to a method in the ViewController.

Solution 1: Move addTarget into the ViewController

The simplest solution is to set up the button’s target within the viewDidLoad method of your MyViewController. Here’s how to do it:

Modify your UIView class to expose the button (if needed):

[[See Video to Reveal this Text or Code Snippet]]

In your View Controller, set the target for the button in viewDidLoad:

[[See Video to Reveal this Text or Code Snippet]]

This way, when deleteButton is pressed, it will call the showDeleteAlert method in MyViewController.

Solution 2: Using a Proxy Function

If you prefer to keep your button private (which is generally a good practice), you can add a proxy function in MyView. This will allow you to set the target externally without directly exposing the button.

Add a proxy method to MyView:

[[See Video to Reveal this Text or Code Snippet]]

Call this proxy function from your ViewController:

[[See Video to Reveal this Text or Code Snippet]]

Key Takeaways

Always pass an instance of the class (the ViewController in this case) when setting the target for UI components.

Keeping your UI component code and logic separated improves your application's architecture, which is in line with the MVC pattern.

Using proxy methods can help maintain encapsulation and keep the button’s visibility limited to the view.

By following these steps and recommendations, you can effectively manage button actions within your Swift applications, maintaining a clean and organized code structure. Happy coding!