CLLocationManager region monitoring delegate class issue - ios

Question

I have implemented a custom class around CoreLocation to do iBeacon region monitoring.
This class has some custom properties that i'm using to store some information related to beacons for later use (during entry and exit events).
The problem that I'm facing is when the app is terminated or kept in background these stored properties are no more available. By that I mean, let's say the app found a beacon region while in background/terminated, as usual the app will be launched in the background for us to process. I wanted to use the stored properties for custom operations during that time.
Did anyone faced this issue before? Am I doing this in a wrong way? Also, I am using this class from a cocoapod library that I'm currently working.
Below is the class that I wrote.
#available(iOS 9.0, *)
class BeaconManager: NSObject, CLLocationManagerDelegate {
//these properties are becoming nil
private var manager: CLLocationManager
private var lastDetection: NSDate?
private var isMonitoring = false
private var repository: [String: DBeacon]
private var monitoredRegions: [String: DBeacon] becoming nil
private var notifyBackground = true
static let sharedManager = BeaconManager()
weak var delegate:BeaconProtocol?
private override init() {
manager = CLLocationManager()
repository = [:]
monitoredRegions = [:]
if CLLocationManager.authorizationStatus() != .AuthorizedAlways {
manager.requestAlwaysAuthorization()
}
super.init()
manager.delegate = self
}
func startMonitoringForBeacon(beacon: Beacon) throws {
guard CLLocationManager.locationServicesEnabled() else {
CFLogger.ERROR("Location services not enabled")
throw BeaconErrorDomain.AuthorizationError(msg: "Location services not enabled")
}
guard CLLocationManager.authorizationStatus() == .AuthorizedAlways else {
switch CLLocationManager.authorizationStatus() {
case .Denied:
throw BeaconErrorDomain.AuthorizationError(msg: "User denied location services")
case .Restricted:
throw BeaconErrorDomain.AuthorizationError(msg: "App is prevented from accessing Location Services")
default:
throw BeaconErrorDomain.AuthorizationError(msg: "App doesn't have authorization to monitor regions")
}
}
guard CLLocationManager.isMonitoringAvailableForClass(CLBeaconRegion) else {
CFLogger.ERROR("Region monitoring not available on this device")
throw DBeaconKitErrorDomain.RegionMonitoringError(msg: "Region monitoring not available on this device")
}
guard let auuid = NSUUID(UUIDString: beacon.uuid) else {
throw BeaconErrorDomain.InvalidUUIDString
}
let region:CLBeaconRegion!
switch (beacon.major, beacon.minor) {
case (.None, .None):
region = CLBeaconRegion(proximityUUID: auuid, identifier: dbeacon.identifier)
case (.Some(let major), .None):
region = CLBeaconRegion(proximityUUID: auuid, major: UInt16(major), identifier: beacon.identifier)
case (.Some(let major), .Some(let minor)):
region = CLBeaconRegion(proximityUUID: auuid, major: UInt16(major), minor: UInt16(minor), identifier: beacon.identifier)
default:
throw BeaconErrorDomain.InvalidDBeaconInfo
}
region.notifyEntryStateOnDisplay = false
region.notifyOnEntry = true
region.notifyOnExit = true
repository[beacon.identifier] = beacon
manager.startMonitoringForRegion(region)
}
func stopMonitoringForBeacons(beacons: [Beacon]) {
guard isMonitoring else {
return
}
beacons.forEach { (dbeacon) -> () in
stopMonitoringForBeacon(beacon)
}
}
func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
guard let handler = delegate else {
return
}
handler.initializationFailed(error)
}
func locationManager(manager: CLLocationManager, didStartMonitoringForRegion region: CLRegion) {
guard let aregion = region as? CLBeaconRegion, beacon = repository[aregion.identifier] else {
return
}
isMonitoring = true
monitoredRegions[aregion.identifier] = beacon
manager.requestStateForRegion(region)
}
func locationManager(manager: CLLocationManager, monitoringDidFailForRegion region: CLRegion?, withError error: NSError) {
guard let aregion = region as? CLBeaconRegion, beacon = repository[aregion.identifier], handler = delegate else {
return
}
handler.monitoringFailedForRegion(beacon, error: error)
}
func locationManager(manager: CLLocationManager, didEnterRegion region: CLRegion) {
guard let aregion = region as? CLBeaconRegion else {
return
}
guard let beacon = monitoredRegions[aregion.identifier] else {
return
}
guard let handler = delegate else {
print("Handler not available to report beacon entry event \(region.identifier)")
return
}
print("Entered beacon region \(beacon)")
handler.entered(beacon)
}
func locationManager(manager: CLLocationManager, didExitRegion region: CLRegion) {
guard let aregion = region as? CLBeaconRegion, beacon = monitoredRegions[aregion.identifier], handler = delegate else {
print("Handler not available to report beacon exit event \(region.identifier)")
return
}
print("Exited beacon region \(beacon)")
handler.exited(beacon)
}
}
I ended up finding that stored properties doesn't have the values that I set while initiating region monitoring.
Any help is truly appreciated.
Regards.

Answer 1

The properties are losing their initialization values on app restarts as #Paulw11 said. The typical way to handle this is to store these properties into NSUserDefaults. The snippet below shows how you would restore the lastDetection field in the bottom of the init method. A second method called save() would have to be called to persist that field once changed.
private override init() {
manager = CLLocationManager()
repository = [:]
monitoredRegions = [:]
if CLLocationManager.authorizationStatus() != .AuthorizedAlways {
manager.requestAlwaysAuthorization()
}
super.init()
manager.delegate = self
let userDefaults = NSUserDefaults.standardUserDefaults()
lastDetection = userDefaults.valueForKey("last_detection") as! NSDate?
}
func save() {
let userDefaults = NSUserDefaults.standardUserDefaults()
userDefaults.setValue(lastDetection, forKey: "last_detection")
}
The example above only shows saving and restoring a single of your properties. You would need to do this with all of them, and some would be more complicated to deal with (like monitoredRegions and repository) because they are complex data types that can't directly be serialized to NSUserDefaults. To do this serialization, you might try using JSON to convert them to a string you can store and then parse them out from that same string.