Understanding Background Location Services on iOS

Background location services allow your app to access device location data even when it’s not in the foreground. This feature is essential for many apps, such as weather forecasting, social media sharing, or ride-hailing services. In this article, we’ll delve into the world of background location services, explore why they might stop working after a short period, and provide guidance on how to fix common issues.

Introduction to Background Location Services

Background location services are a feature introduced in iOS 7 that enables apps to access device location data even when they’re not in the foreground. This feature is implemented using the CLLocationManager class, which provides methods for obtaining location updates, such as startUpdatingLocation() and didUpdateToLocation(_:fromLocation:).

When an app starts running in the background, it can request background location access through the NSLocationWhenInUseUsageDescription key in its Info.plist file. If this permission is granted by the user, the app can continue to receive location updates until it’s terminated.

The Problem: Location Services Stopping After a Short Period

The original poster was experiencing an issue where their background location services stopped working after a short period (usually around 1 minute). This problem was observed when trying to get a device location and compare it with a location online, all happening in the background. The method they created using background location service was working fine initially but stopped working once the location icon in the status bar disappeared.

Understanding the Issue

The main issue here is that background location services are only allowed to run for a limited period (usually around 1 minute) before the system terminates them and stops providing location updates. To work around this limitation, apps can use techniques such as:

• Using the startMonitoringSignificantLocationChanges() method, which allows the app to receive location updates when the device is moving at an unprecedented rate.
• Implementing a timer to periodically refresh location data.
• Using a separate thread or background process to perform long-running tasks.

However, these workarounds may not be sufficient in all cases. The original poster’s solution involved using a different approach to handle the issue: modifying their Info.plist file and handling notifications when location services are stopped.

Modifying the Info.plist File

To fix the issue, the developer needs to modify their app’s Info.plist file by adding a key called Required background modes with an item value of App registers for location updates. This tells the system that your app requires permission to access location data even when it’s not in the foreground.

Here’s how you can add this configuration:

1. Open your project in Xcode.
2. Go to the Product menu and select Edit Scheme.
3. Click on the Info tab.
4. In the Navigation Bar, click on the “+” button at the bottom left corner of the screen.
5. Select “Add New Configuration Profile” from the dropdown menu.
6. In the Configuration Profiles window, click on the “+” button to add a new configuration profile.
7. Select the “iOS” template and create a new configuration profile with the name Your App Name - Background Location Services.
8. Add the key-value pair for Required background modes:

Handling Notifications When Location Services Are Stopped

Another issue to consider is handling notifications when location services are stopped. In the original poster’s solution, they implemented a notification handler using the UILocalNotification class.

Here’s how you can handle this:

1. Create a local notification object:

UILocalNotification *notify = [[UILocalNotification alloc] init];
notify.alertAction = @"View";
notify.fireDate = nil;
notify.alertBody = [NSString stringWithFormat:@"New Data Occured"];
notify.soundName = UILocalNotificationDefaultSoundName;

2. Present the local notification using [UIApplication sharedApplication] presentLocalNotificationNow:notify];.

Using a Timer to Refresh Location Data

If you’re experiencing issues with location services stopping after a short period, you might want to consider implementing a timer to periodically refresh location data.

Here’s an example of how you can use a timer:

NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:30.0 // Update every 30 seconds
        target:self
        selector:@selector(updateLocation)
        userInfo:nil
        repeats:YES];

This code creates a timer that updates location data every 30 seconds.

Conclusion

Background location services are an essential feature for many apps, but they can be finicky to work with. By modifying your Info.plist file and handling notifications when location services are stopped, you can ensure that your app continues to receive location updates even when it’s not in the foreground.

Additionally, using techniques such as timers or separate threads can help overcome limitations imposed by background location services. However, these solutions may require careful consideration of performance and battery life.

By following this guide, you should be able to resolve issues with background location services on iOS and provide a seamless experience for your users.

Last modified on 2023-10-18