iOS - Location Handling

Advertisements


Introduction

In iOS we can easily locate the user's current location provided the user allows the application to access the information with the help of core location framework.

Steps Involved

1. Create a simple View based application.

2. Select your project file, then select targets and then add CoreLocation.framework as shown below.

iOS Tutorial

3. Add two labels in ViewController.xib and create ibOutlets naming the labels as latitudeLabel and longitudeLabel respectively.

4. Now create a new file by selecting File-> New -> File... -> select Objective C class and click next

5. Name the class as LocationHandler with "sub class of" as NSObject.

6. Select create.

7. Now update the LocationHandler.h as follows

#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>

@protocol LocationHandlerDelegate <NSObject>

@required
-(void) didUpdateToLocation:(CLLocation*)newLocation 
 fromLocation:(CLLocation*)oldLocation;
@end

@interface LocationHandler : NSObject<CLLocationManagerDelegate>
{
    CLLocationManager *locationManager;
}
@property(nonatomic,strong) id<LocationHandlerDelegate> delegate;

+(id)getSharedInstance;
-(void)startUpdating;
-(void) stopUpdating;

@end

8. Now update the LocationHandler.m as follows

#import "LocationHandler.h"
static LocationHandler *DefaultManager = nil;

@interface LocationHandler()

-(void)initiate;

@end

@implementation LocationHandler

+(id)getSharedInstance{
    if (!DefaultManager) {
        DefaultManager = [[self allocWithZone:NULL]init];
        [DefaultManager initiate];
    }
    return DefaultManager;
}
-(void)initiate{
    locationManager = [[CLLocationManager alloc]init];
    locationManager.delegate = self;
}

-(void)startUpdating{
    [locationManager startUpdatingLocation];
}

-(void) stopUpdating{
    [locationManager stopUpdatingLocation];
}
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:
 (CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{
    if ([self.delegate respondsToSelector:@selector
    (didUpdateToLocation:fromLocation:)]) 
    {
        [self.delegate didUpdateToLocation:oldLocation 
        fromLocation:newLocation];

    }
}

@end

9. Update ViewController.h as follows where we have implemented the LocationHandler delegate and create two ibOutlets.

#import <UIKit/UIKit.h>
#import "LocationHandler.h"
@interface ViewController : UIViewController<LocationHandlerDelegate>
{
    IBOutlet UILabel *latitudeLabel;
    IBOutlet UILabel *longitudeLabel;
}
@end

10. Update ViewController.m as follows

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    [[LocationHandler getSharedInstance]setDelegate:self];
    [[LocationHandler getSharedInstance]startUpdating];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

-(void)didUpdateToLocation:(CLLocation *)newLocation 
 fromLocation:(CLLocation *)oldLocation{
    [latitudeLabel setText:[NSString stringWithFormat:
    @"Latitude: %f",newLocation.coordinate.latitude]];
    [longitudeLabel setText:[NSString stringWithFormat:
    @"Longitude: %f",newLocation.coordinate.longitude]];

}

@end

Output

Now when we run the application we'll get the following output.

iOS Tutorial



Advertisements
Advertisements