The Importance of State Restoration in iOS Apps

In iOS applications, preserving user interface state is essential to provide a seamless user experience. Imagine a user working on a long document or an eCommerce application with a full cart, and suddenly, they close the app or switch to another app. If the app fails to restore the user interface state, the user would lose all their progress, leading to frustration and the possibility of abandoning the app altogether.

Fortunately, iOS provides built-in mechanisms to preserve and restore the user interface state. In this article, we will explore the basics of state preservation and restoration, discuss best practices for implementing state restoration in your iOS app, and explain how it can enhance the user experience.

Understanding the Basics of State Preservation and Restoration

The state of an iOS application consists of various user interface elements, such as view controllers, navigation controllers, tab bars, and more. State preservation and restoration refer to the processes of saving and restoring these user interface elements’ state when an application goes into the background or terminates.

To implement state preservation and restoration, iOS provides two main classes – UIViewController and UIApplication. The UIViewController class has two methods – encodeRestorableStateWithCoder() and decodeRestorableStateWithCoder() – that allow the saving and restoring of the view controller’s state. On the other hand, the UIApplication class has a delegate method – application(_:willFinishLaunchingWithOptions:) – that informs the app delegate when the app is about to launch and provides an opportunity to restore the user interface state.

Implementing State Restoration in Your iOS App: Best Practices

To implement state restoration in your iOS app, you need to follow these best practices:

1. Identify the user interface elements that need state preservation and restoration. These typically include view controllers, navigation controllers, tab bars, and more.

2. Implement the encodeRestorableStateWithCoder() and decodeRestorableStateWithCoder() methods in your view controllers to save and restore their state.

3. Implement the application(_:shouldSaveApplicationState:) and application(_:shouldRestoreApplicationState:) methods in your app delegate to indicate which parts of the app state need to be saved and restored.

4. Enable state preservation and restoration by setting the restorationIdentifier property for each view controller that needs to be restored.

5. Test your app thoroughly to ensure that the state restoration works as expected.

Conclusion: Enhancing User Experience through State Restoration

In conclusion, implementing state restoration in your iOS app is essential to provide a seamless user experience. By preserving the user interface state, you can prevent users from losing their progress and improve their satisfaction with the app. Understanding the basics of state preservation and restoration and following the best practices discussed in this article can help you implement state restoration effectively. By enhancing the user experience through state restoration, you can increase user engagement, retention, and loyalty.