Question

I am completely new to iOS development so I may be doing this wrong but I have a class I am using to get coordinate gps data that I want to have as a generic class I can reuse in lots of apps. My problem is getting the data from the gps to properly display in other apps.

Here is my header file for the GPS class:

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

@interface LocationAwareness : NSObject <CLLocationManagerDelegate> {
CLLocationManager *locationManager;
}
@property(copy) NSString *longitude;
@property(copy) NSString *latitude;

@end

And here is the implementation:

#import "LocationAwareness.h"

@implementation LocationAwareness
@synthesize longitude;
@synthesize latitude;


- (id)init {

locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; // 100 m
[locationManager startUpdatingLocation];
return self;
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation   *)newLocation fromLocation:(CLLocation *)oldLocation {

    // Stops updating location if data has been updated within 10 minutes
    if ( abs([newLocation.timestamp timeIntervalSinceDate: [NSDate date]]) < 600) {

        [locationManager stopUpdatingLocation];
        float latitudedata = newLocation.coordinate.latitude;
        latitude = [NSString stringWithFormat:@"%f", latitudedata];

        float logitudedata = newLocation.coordinate.longitude;
        longitude = [NSString stringWithFormat:@"%f", logitudedata];

    }
}

@end

Now I can’t seem to find anywhere that tells me how to get the latitude or longitude properties in another project. I have the header imported and have tried to store LocationAwareness.latitude into a variable that I can use but everything I store it in ends up blank. When I start my main class and aloc init a locationawareness object the gps fires up so I think its working but I don’t seem to know enough about how this works to get everything in order. I’ve been searching the internet for hours. Anyone have an idea what I am doing wrong?

Answer 1

Well, this may or may not be causing the problem (it’s quite likely), but a major problem is your init method.

The beginning should be:

self = [super init];
if (self) {
    // Do your initializing as you did above.
}
return self;

edit:
I added your code with my update to a project and it works well.
In order to use this, you should do something like the following:

LocationAwareness *loc = [[LocationAwareness alloc] init];

// Give it some time to start updating the current location and then
// in a different function:
NSLog(@"%@", loc.latitude);

EDIT 2
Wherever you are using this, you will want to declare a property which stores it so that you can create it once and reference it many times. To do that, use the following code:

In the header for the object where you want to use this object, add this with the other properties:

@property (nonatomic, assign) LocationAwareness *location;

Then, towards the top of your implementation file (.m file) you should see other @synthesize lines, add this one:

@synthesize location;

Then, create the actual location instance that you want to use as per the example above:

self.location = [[LocationAwareness alloc] init];

Now give it some time to figure out your location and start providing updates. Then you can print the location like this:

NSLog(@"%@", self.location.latitude);