How to scan multiple regions using startMonitoringForRegion in Objective-C

Question

I've been through two tutorials and am reading up on basic C. Learn best through doing and have written a few light apps in the past week or so. Am getting up to speed to write some apps that will use ibeacon. As I'm going through some samples and reading the reference guide I see that multiple regions can be scanned by running startMonitoringForRegion for each UUID. OK, so I figure I could just run it for each UUID but that's not working. I'm sure I'm doing something basic totally wrong... the code below is a total hack - once I get the semantics I will pull the UUIDs from a DB with an API call and than loop through them to activate the monitoring. The code below results in last loop only showing two of the four UUIDs.

in header:

@property (strong, nonatomic) CLBeaconRegion *myBeaconRegion;
@property (strong, nonatomic) CLBeaconRegion *myBeaconRegion2;
@property (strong, nonatomic) CLBeaconRegion *myBeaconRegion3;
@property (strong, nonatomic) CLBeaconRegion *myBeaconRegion4;

in main:

NSUUID *uuid = [[NSUUID alloc] initWithUUIDString:@"86E4BDEA-C6FF-442C-95CB-E6E557A23CF2"];
self.myBeaconRegion = [[CLBeaconRegion alloc] initWithProximityUUID:uuid identifier:@"com.appcoda.testregion"];

NSUUID *uuid2 = [[NSUUID alloc] initWithUUIDString:@"C9AFF296-A722-4F2D-8669-47B7CCC79A14"];
self.myBeaconRegion2 = [[CLBeaconRegion alloc] initWithProximityUUID:uuid2 identifier:@"com.appcoda.testregion"];

NSUUID *uuid3 = [[NSUUID alloc] initWithUUIDString:@"1DBDDC7C-49BB-48BF-A2F6-A4825BD514EA"];
self.myBeaconRegion3 = [[CLBeaconRegion alloc] initWithProximityUUID:uuid3 identifier:@"com.appcoda.testregion"];

NSUUID *uuid4 = [[NSUUID alloc] initWithUUIDString:@"8D942B9E-0197-4C81-8722-92144599E9F7"];
self.myBeaconRegion4 = [[CLBeaconRegion alloc] initWithProximityUUID:uuid4 identifier:@"com.appcoda.testregion"];

[self.locationManager startMonitoringForRegion:self.myBeaconRegion];
[self.locationManager startMonitoringForRegion:self.myBeaconRegion2];
[self.locationManager startMonitoringForRegion:self.myBeaconRegion3];
[self.locationManager startMonitoringForRegion:self.myBeaconRegion4];

NSSet *setOfRegions = [self.locationManager monitoredRegions];
    for (CLRegion *region in setOfRegions) {
        NSLog (@"region info: %@", region);
    }

Answer 1

I think the problem is your region identifiers. Each beacon region identifier must be unique, otherwise CLLocationManager treats them as the same region.

Try setting a unique identifier for each region:

NSUUID *uuid = [[NSUUID alloc] initWithUUIDString:@"86E4BDEA-C6FF-442C-95CB-E6E557A23CF2"];
self.myBeaconRegion = [[CLBeaconRegion alloc] initWithProximityUUID:uuid identifier:@"com.appcoda.testregion"];

NSUUID *uuid2 = [[NSUUID alloc] initWithUUIDString:@"C9AFF296-A722-4F2D-8669-47B7CCC79A14"];
self.myBeaconRegion2 = [[CLBeaconRegion alloc] initWithProximityUUID:uuid2 identifier:@"com.appcoda.testregion2"];

NSUUID *uuid3 = [[NSUUID alloc] initWithUUIDString:@"1DBDDC7C-49BB-48BF-A2F6-A4825BD514EA"];
self.myBeaconRegion3 = [[CLBeaconRegion alloc] initWithProximityUUID:uuid3 identifier:@"com.appcoda.testregion3"];

NSUUID *uuid4 = [[NSUUID alloc] initWithUUIDString:@"8D942B9E-0197-4C81-8722-92144599E9F7"];
self.myBeaconRegion4 = [[CLBeaconRegion alloc] initWithProximityUUID:uuid4 identifier:@"com.appcoda.testregion4"];

You should see each region listed from your NSLog statement. No need for dispatch_async, either.