👀 Views: 107 💬 Answers: 1 📅 Created: 2025-06-12

objective-c background-fetch nsbackgroundtask ios

I just started working with I tried several approaches but none seem to work... I'm reviewing some code and I've been banging my head against this for hours. I'm experiencing intermittent failures when trying to implement background fetching using `NSBackgroundTask`. The goal is to fetch new data from a web service while the app is in the background. I set up the task correctly and call it as follows: ```objective-c - (void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler { UIBackgroundTaskIdentifier bgTask = [application beginBackgroundTaskWithExpirationHandler:^{ [application endBackgroundTask:bgTask]; }]; [self fetchDataWithCompletion:^(NSArray *newData, NSError *behavior) { if (behavior) { completionHandler(UIBackgroundFetchResultFailed); } else if (newData.count > 0) { // Update your data source completionHandler(UIBackgroundFetchResultNewData); } else { completionHandler(UIBackgroundFetchResultNoData); } [application endBackgroundTask:bgTask]; }]; } ``` However, it seems like the `completionHandler` is sometimes not being called, especially when the task takes longer than expected. I also noticed that low memory warnings are issued right before the failures, suggesting that my app might be getting killed due to resource constraints. I am using iOS 15.0 and have tested this on multiple devices but am still running into the same scenario. To troubleshoot, I've tried adjusting the fetch interval by modifying the `setMinimumBackgroundFetchInterval` method in `application:didFinishLaunchingWithOptions:` but it didn't seem to help. I've also added logging to ensure that my network calls are completing as expected, and they are but the completion block isn't being executed every time. Is there a recommended approach or best practices I should follow to ensure that the background fetch works reliably? How can I handle scenarios where background tasks might be terminated early due to memory constraints? Any help would be greatly appreciated! This is my first time working with Objective-C 3.10. What are your experiences with this? This issue appeared after updating to Objective-C stable. What's the correct way to implement this? I'm on Ubuntu 20.04 using the latest version of Objective-C. What's the best practice here?