在哪里集中注意力？

这是我的班级定义：

#import "BeaconManager.h"

@implementation BeaconManager

- (instancetype)init {
    self = [super init];
    if (self) {
        NSURL *beep = [[NSBundle mainBundle] URLForResource:@"beep" withExtension:@"aiff"];
        soundFileURLRef = (CFURLRef) CFBridgingRetain(beep);
        AudioServicesCreateSystemSoundID(soundFileURLRef,&soundFileObject);

        // Initializes properties
        beacon = [CLBeacon new];
        foundBeacons = [NSMutableArray new];
        _lastBeaconActionTimes = [[NSMutableDictionary alloc] init];
    }
    return self;
}

- (void)initRegion {
    // Initializes the beacon region by giving it an UUID and an identifier
    NSUUID *uuid = [[NSUUID alloc] initWithUUIDString:BEACON];
    beaconRegion = [[CLBeaconRegion alloc] initWithProximityUUID:uuid identifier:@"beacon.region"];
    // Starts looking for beacon within the region
    [self.locationManager startMonitoringForRegion:beaconRegion];
}

- (void)checkBeacon {
    if (!self.locationManager) {
        self.locationManager = [[CLLocationManager alloc] init];
        self.locationManager.delegate = self;

        if ([self.locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)])
            [self.locationManager requestWhenInUseAuthorization];
    }
    [self initRegion];
    [self locationManager:self.locationManager didStartMonitoringForRegion:beaconRegion];
}

#pragma mark - CLLocationManagerDelegate

- (void)locationManager:(CLLocationManager *)manager didStartMonitoringForRegion:(CLRegion *)region {
    [self.locationManager startMonitoringForRegion:beaconRegion];
    [self.locationManager startRangingBeaconsInRegion:beaconRegion];
}

- (void)locationManager:(CLLocationManager *)manager didEnterRegion:(CLRegion *)region {
    [self.locationManager startRangingBeaconsInRegion:beaconRegion];
}

- (void)locationManager:(CLLocationManager *)manager didExitRegion:(CLRegion *)region {
    [self.locationManager stopRangingBeaconsInRegion:beaconRegion];
}

- (void)locationManager:(CLLocationManager *)manager monitoringDidFailForRegion:(CLRegion *)region withError:(NSError *)error {
    NSLog(@"Failed monitoring region: %@",error);
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
    NSLog(@"Location manager Failed: %@",error);
}

- (void)locationManager:(CLLocationManager *)manager
        didRangeBeacons:(NSArray *)beacons
               inRegion:(CLBeaconRegion *)region {

    if (foundBeacons.count == 0) {
        for (CLBeacon *filterBeacon in beacons) {
            // If a beacon is located near the device and its major value is equal to 1000 (MAJOR constant)
            if (((filterBeacon.proximity == CLProximityImmediate) || (filterBeacon.proximity == CLProximityNear)))
                // Registers the beacon to the list of found beacons
                [foundBeacons addObject:filterBeacon];
        }
    }
    // Did some beacon get found?
    if (foundBeacons.count > 0) {
        // Takes first beacon of the list
        beacon = [foundBeacons firstObject];

        if (([beacon.major isEqualToNumber:[NSNumber numberWithInt:MAJOR]]) && ([beacon.minor isEqualToNumber:[NSNumber numberWithInt:MINOR]])) {
            // Takes the actual date and time
            NSDate *now = [[NSDate alloc] init];
            NSString *key = [NSString stringWithFormat:@"%@ %@ %@",[beacon.proximityUUID UUIDString],beacon.major,beacon.minor];
            NSDate *lastBeaconActionTime = [_lastBeaconActionTimes objectForKey:key];
            if ((lastBeaconActionTime == nil) || ([now timeIntervalSinceDate:lastBeaconActionTime] > MINIMUM_ACTION_INTERVAL_SECONDS)) {
                [_lastBeaconActionTimes setObject:now forKey:key];
                // Plays beep sound
                AudioServicesPlaySystemSound(soundFileObject);

                if (self.delegate) {
                    // Performs actions related to the beacon (i.e. delivers a coupon)
                    [self.delegate didFoundBeacon:self];
                }
                self.locationManager = nil;
            }
            // else [self.locationManager stopMonitoringForRegion:region];
        }
        [foundBeacons removeObjectAtIndex:0];
        beacon = nil;
    }
}
@end