App Delegate Methods Not Being Called in iOS 13: A Comprehensive Guide

Introduction:

Are you facing issues with your iOS 13 app where the app delegate methods are not being called? You’re not alone! In this article, we will dive into the changes introduced in iOS 13 and how they affect the way app lifecycle events are handled. We’ll explore the new UIWindowSceneDelegate and UISceneDelegate protocols, and provide solutions to ensure your app delegate methods are invoked correctly.

Understanding the iOS 13 Changes:

With the advent of iOS 13, Apple introduced a new way of handling app lifecycle events. Instead of relying solely on the UIApplicationDelegate, these events are now routed through the UIWindowSceneDelegate protocol, a sub-protocol of UISceneDelegate. This change was made to support multiple windows in iOS 13.

The Impact on App Delegate Methods:

Due to this transition, some app delegate methods that were previously called directly are no longer invoked as expected. These include methods such as applicationDidEnterBackground and applicationWillEnterForeground. Instead, the new UISceneDelegate methods take precedence.

Working with UIWindowSceneDelegate:

To adapt your app for iOS 13, you need to implement the UIWindowSceneDelegate methods in addition to the existing app delegate methods. This enables your app to handle the new lifecycle events correctly.

Here’s a step-by-step guide to help you ensure the proper implementation:

1. Check for “Application Scene Manifest” in Info.plist:
   • If present, your app delegate won’t receive certain lifecycle messages.
   • Remove this entry to revert to the old behavior.
2. Implement configurationForConnectingSceneSession:
   • If you have the “Application Scene Manifest,” this method is necessary.
   • Return a UISceneConfiguration object with the appropriate session role.
3. Handling Old Behavior:
   • If you want to revert to the old behavior entirely, remove the “Application Scene Manifest” and the configurationForConnectingSceneSession method.
   • Don’t forget to add back the window property to your app delegate.
4. Utilizing SceneDelegate:
   • You can alternatively use the new lifecycle methods in the SceneDelegate file created by Xcode.
   • Implement methods like sceneDidBecomeActive and sceneWillResignActive to handle the respective events.

Exploring UISceneDelegate Benefits:

The transition to the UISceneDelegate offers more than just handling app lifecycle events. It also provides support for user activities, state restoration, status bar queries, and opening URLs. Be sure to leverage these functionalities to enhance your app’s user experience.

Understanding the Changes in iOS 13

• Explain the changes introduced in iOS 13 regarding app lifecycle events.
• Discuss the transition from UIApplicationDelegate to UIWindowSceneDelegate and UISceneDelegate.
• Mention the purpose of UIWindowSceneDelegate and its role in supporting multiple windows.

Common Causes for App Delegate Methods Not Being Called

• List potential reasons why app delegate methods may not be invoked in iOS 13.
• Include possible scenarios such as missing configuration or improper implementation.

Step-by-Step Solutions

• Provide a step-by-step guide to troubleshoot and fix the issue.
  • Check the “Application Scene Manifest” entry in Info.plist.
  • Implement the configurationForConnectingSceneSession method.
  • Address the impact on the old behavior and how to revert if necessary.
  • Explain the utilization of SceneDelegate for handling app lifecycle events.

Best Practices for App Lifecycle Management in iOS 13

• Offer recommendations for developers to ensure smooth app lifecycle management.
  • Emphasize the importance of adopting the new UISceneDelegate methods.
  • Discuss utilizing the additional capabilities of UISceneDelegate (e.g., user activities, state restoration).
  • Highlight the significance of testing and debugging in iOS 13 environment.