`BGAppRefreshTask` Handler Not Being Called Despite Proper Setup in iOS App

Question

I’m working on implementing a background task in my iOS app using BGAppRefreshTask. I’ve followed all the steps to set it up, but the background task did not work for the background and terminated application states. Here’s what I’ve done so far:

Setup Details:

1. Signing & Capabilities Configuration: Enabled Background fetch and Background Processing options.

2. Info.plist Configuration: I’ve added the BGTaskSchedulerPermittedIdentifiers key with my background task identifier (e.g., "com.example.myapp.refresh").

3. Registering the Background Task: In application(_:didFinishLaunchingWithOptions:), I call the registerBackgroundTask() method to register the task:

   func registerBackgroundTask() {
       BGTaskScheduler.shared.register(forTaskWithIdentifier: "com.example.myapp.refresh", using: nil) { task in
           guard let task = task as? BGAppRefreshTask else {
               return
           }
           Task {
               await self.scheduleNotificationIfNeeded()
               task.setTaskCompleted(success: true)
           }
           task.expirationHandler = {
               print("BGAppRefreshTask is expired")
           }
       }
   }
   

4. Scheduling the Task: I’m scheduling the task like this:

   let request = BGAppRefreshTaskRequest(identifier: "com.example.myapp.refresh")
   request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60) // 15 minutes later for testing.
   
   do {
       try BGTaskScheduler.shared.submit(request)
   } catch {
       print("Failed to submit BGAppRefreshTaskRequest: \(error)")
   }
   

5. Testing Conditions: I've tested all these conditions with a physical device and not with a simulator. I learned that it's not working in Simulator. Here is the conditions that I gave a try:

• I've tried both the app is in background & terminated states and wait for the task to trigger, There is no triggered notification.
• I've verified that:
  • The task identifier in the code matches the one in Info.plist.
  • The registerBackgroundTask function is being called in application(_:didFinishLaunchingWithOptions:).
  • The task is scheduled with an earliestBeginDate of 61 seconds for testing.

6. Debugging Attempts:

• Added print statements to see if the handler is called (it's not) in the background app state.
• Used Xcode’s Simulate Background Fetch debug option to trigger the background task, but still no luck.
• Verified that the device is not in Low Power Mode and Background app refresh toggle is ON in the app settings.

Question: What could be causing the BGAppRefreshTask does not work despite having everything seemingly set up correctly? Is there anything else I should be checking or any potential issues with iOS’s background task handling that could be causing this?

Any guidance or troubleshooting tips would be greatly appreciated!

Result:

After thorough research, I discovered that there is no guaranteed solution for ensuring the execution of background tasks in iOS. The iOS system uses an internal prioritization mechanism that depends heavily on the current device state and user behavior. Consequently, it is not advisable to rely on background tasks for handling critical business cases, as iOS makes its own decision on whether to execute the task based on several factors.

Some key factors influencing iOS's decision-making process include:

1) User Activity: If the user is not a frequent user of the app, iOS may deprioritize or even skip the scheduled background task execution.

2) Manual App Termination: If the user forcefully kills the app, any scheduled background tasks will not be executed.

3) Low Power Mode: When Low Power Mode is enabled, iOS may delay or prevent background task execution to conserve battery life.

4) Battery Level: If the device's battery is low, iOS may choose to delay or skip the task in order to optimize power consumption.

These factors, among others, illustrate the inherent uncertainty in relying on background tasks for time-sensitive operations in iOS.