CODEWITHSUNDEEP
xcodemkmapview
Bobbbaa
Bobbbaa

Reputation: 199

MKmapview - CLLocationCoordinate2D

I have an array NSMutableArray where I save an MKuserlocation type - locationArray. anyway now I want to get the data from this array and save it to an array from type CLLocationCoordinate2D. but since everything I save in locationArray is from id type how can I get the coordinates from this and save it to the second array?

  CLLocationCoordinate2D* coordRec = malloc(pathLength * sizeof(CLLocationCoordinate2D));
    for(id object in locationArray){
        for (int i = 0; i < pathLength; i++)
            ?????

I dont know if this even possible!

Thanks

Upvotes: 1

Views: 1905

Answers (3)

TomSwift
TomSwift

Reputation: 39502

Why do you need a c-style array of CLLocationCoordinate2D objects?

Here you go:

NSArray* userLocations; // contains your MKUserLocation objects...

CLLocationCoordinate2D* coordinates = malloc( userLocations.count * sizeof( CLLocationCoordinate2D) );

for ( int i = 0 ; i < userLocations.count ; i++ )
{
    coordinates[i] = [[[userLocations objectAtIndex: i] location] coordinate];
}

Upvotes: 1

Rob
Rob

Reputation: 438162

The typical solution is to create a NSObject subclass and define a single property, a CLLOcationCoordinate2D. Instantiate and add those objects to your array.

@interface Coordinate : NSObject

@property (nonatomic) CLLocationCoordinate2D coordinate;

- (id)initWithCoordinate:(CLLocationCoordinate2D)coordinate;

@end

@implementation Coordinate

- (id)initWithCoordinate:(CLLocationCoordinate2D)coordinate
{
    self = [super init];
    if (self) {
        _coordinate = coordinate;
    }
    return self;
}

@end

And then, because your locationArray is an array of MKUserLocation (which, itself, conforms to MKAnnotation), you can do:

NSMutableArray *path;

path = [NSMutableArray array];
for (id<MKAnnotation> annotation in locationArray)
{
    // determine latitude and longitude

    [path addObject:[[Coordinate alloc] initWithCoordinate:annotation.coordinate]];
}

Or make an array of existing object type, such as CLLocation or MKPinAnnotation or whatever.

Or if this array is a path to be drawn on the map, you might want to avoid using your own array, and instead make a MKPolyline. 

NSInteger pathLength = [locationArray count];
CLLocationCoordinate2D polylineCoordinates[pathLength];  // note, no malloc/free needed
for (NSInteger i = 0; i < pathLength; i++)
{
    id<MKAnnotation> annotation = locationArray[i];

    polylineCoordinates[i] = annotation.coordinate;
}
MKPolyline *polyline = [MKPolyline polylineWithCoordinates:polylineCoordinates count:pathLength]
[self.mapView addOverlay:polyline];

It depends upon what the purpose of this is. But if you can use one of the previous constructs that avoids malloc and free, that's probably ideal. These techniques leverage Objective-C patterns which make it harder to leak, use an invalid pointer, etc.

Upvotes: 0

fencingCode
fencingCode

Reputation: 1427

Refering to Apple docs

You should certainly use CLLocationCoordinate2DMake function with data from MKUserLocation or directly extract infos from MKUserLocation:

object.location.coordinate // it's a CLLocationCoordinate2D from your 'object' example

or

CLLocationCoordinate2DMake(object.location.coordinate.latitude, object.location.coordinate.longitude)

Hope this help.

Upvotes: 0

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