Скачать или смотреть How to Change ViewController After REST API Call in Swift

Learn how to seamlessly transition to a new `ViewController` after successfully calling a REST API in Swift!
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This video is based on the question https://stackoverflow.com/q/67172994/ asked by the user 'bircastri' ( https://stackoverflow.com/u/2405663/ ) and on the answer https://stackoverflow.com/a/67173166/ provided by the user 'Vitaly Potlov' ( https://stackoverflow.com/u/2724756/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Change ViewController After REST API Call in Swift

When building iOS applications, it's common to interact with REST APIs to fetch or send data. But what if you need to navigate to a different ViewController automatically after receiving a success response from the API? In this post, we'll explore how to achieve this in Swift, specifically addressing a common issue developers encounter during the process.

The Problem

Imagine you've set up a registration screen where users can input their details and submit this information via a REST API call. You want to automatically transition to a different screen (FirstViewController) upon receiving a success response from the server. However, you may run into an error that states:

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

This error indicates that you're trying to update the UI from a background thread, which is not allowed in iOS development. So how can you solve this?

The Solution

To resolve this issue, we need to ensure that any UI updates, including transitioning to a new ViewController, are executed on the main thread. Here's how to implement this change effectively in your code.

Step-by-Step Implementation

Wrap Your ViewController Transition in DispatchQueue: To make sure your code runs on the main thread, use DispatchQueue.main.async. This can be applied around the code responsible for changing the ViewController.

Here’s the modified part of your registerUser method:

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

Key Points to Remember

UI Updates on Main Thread: Always remember that any UI-related changes must happen on the main thread to avoid errors and ensure smooth performance.

Using weak self: Note the use of [weak self] in the closure. This is a good practice to prevent strong reference cycles that can lead to memory leaks.

Error Handling: While the provided code handles successful API calls, don’t forget to implement user feedback for failure cases as well. For instance, you could show an alert to inform the user about the error.

Conclusion

Transitioning from one ViewController to another after a successful API call involves ensuring that your code runs on the main thread. By following the above steps and best practices, you can implement this functionality seamlessly in your Swift applications.

Now you can enhance user experience in your apps by responding instantly to their actions without waiting for them to click a button!

By ensuring that the UI updates are executed on the main thread, you can effectively resolve any related issues you may encounter during development. Happy coding!