ViewDidAppear is not called when opening app from background

Why Is viewDidAppear Not Called When Opening App from Background? 😕

Have you ever encountered a situation where the viewDidAppear method doesn't get called when you open your app from the background? If so, you're not alone! This is a common issue that many iOS developers face. But fear not, because we're here to help you understand why this happens and how to fix it! 💪

Understanding the Problem 🕵️‍♀️

To understand this issue, let's first take a look at the lifecycle of a view controller when the app launches from the background.

1. When you open the app, the system first calls the applicationWillEnterForeground method in your app delegate.

2. Next, the system calls the applicationDidBecomeActive method, indicating that your app has transitioned from the background to the foreground.

3. Finally, the view controller's methods such as viewDidLoad, viewWillAppear, and viewDidAppear are called in that order.

However, here's the catch – if the view controller is already loaded in memory, the viewDidLoad method will not be called again, as it only gets called when the view controller is being loaded for the first time.

The Solution 🚀

To make sure that your code in viewDidAppear gets executed when the app is launched from the background, you'll need to handle it in the applicationDidBecomeActive method. Here's a step-by-step guide on how to do it:

1. Open your app delegate, which is typically named AppDelegate.swift.

2. Locate the applicationDidBecomeActive method.

3. Inside this method, find the view controller that you want to update and call its viewDidAppear method manually.

func applicationDidBecomeActive(_ application: UIApplication) {
    if let viewController = window?.rootViewController as? YourViewController {
        viewController.viewDidAppear(false)
    }
}

By calling viewDidAppear manually, you ensure that the code inside that method is executed whenever the app becomes active, whether it's launched from the background or not. 🎉

Engage with the Community 🤝

We hope this guide resolved your dilemma and helped you understand why viewDidAppear was not being called when opening the app from the background.

If you have any further questions or insights about this problem, please feel free to leave a comment below. Our community of developers is always ready to help each other out!

Happy coding! 💻😃