Sort user locations iOS - ios

Question

I've an NSArray containing users information of their places, i.e their latitude and longitudes.
I also got the current user's location, now I want to sort out the list of latitudes and longitudes from the NSArray so that the current user can see his nearby users easily.
For instance, I've the following information.
NSArray *ALLINFOLAT = [ALLINFO valueForKey:#"lat"]
// having "40.880048", "40.749315", "40.749278",
NSArray *ALLINFOLNG = [ALLINFO valueForKey:#"lng"]
// having "-77.145461", "-122.258591", "-122.320566"
NSString *currentUserLat = #"78";
NSString *currentUserLng = #"87";
How can I sort out the NSDictionary ALLINFO according to currentUserLat & currentUserLng using NSSortDescriptor.

Answer 1

I think you are confusing people by creating separate arrays for latitude and longitude.
If I understand correctly, you have an array ALLINFO that hold informations about users and their location, and you want to sort it based on distance to the current location.
You didn't specified what objects you have in array, so I assume they are dictionaries.
Here's how you get a sorted array:
CLLocation *currentLocation = [[CLLocation alloc] initWithLatitude: 78 longitude: 87];
NSArray *orderedInfo = [ALLINFO sortedArrayUsingComparator: ^(NSDictionary *object1, NSDictionary *object2)
{
CLLocation *location1 = [[CLLocation alloc] initWithLatitude: [object1[#"lat"] doubleValue] longitude: [object1[#"lng"] doubleValue]];
CLLocation *location2 = [[CLLocation alloc] initWithLatitude: [object2[#"lat"] doubleValue] longitude: [object2[#"lng"] doubleValue]];
CLLocationDistance dist1 = [location1 distanceFromLocation:currentLocation];
CLLocationDistance dist2 = [location2 distanceFromLocation:currentLocation];
if (dist1 < dist2) {
return (NSComparisonResult)NSOrderedAscending;
} else if ( dist1 > dist2) {
return (NSComparisonResult)NSOrderedDescending;
} else {
return (NSComparisonResult)NSOrderedSame;
}
}];

Answer 2

NSMutableArray *ALLINFOLAT =#[#(40.880048), #(40.749315), #(40.749278)];
NSMutableArray *ALLINFOLNG =#[#(-77.145461), #(-122.258591), #(-122.320566)];
NSString *currentUserLat = #"78";
NSString *currentUserLng = #"87";
CLLocation* currentLocation =[[CLLocation alloc]initWithLatitude:[currentUserLat doubleValue] longitude:[currentUserLng doubleValue]];
NSMutableArray* locationArray = [[NSMutableArray alloc]initWithCapacity:[ALLINFOLNG count]];
for (int i=0; i<[ALLINFOLAT count]; i++) {
CLLocationDegrees latValue = [ALLINFOLAT[i] doubleValue];
CLLocationDegrees longValue = [ALLINFOLNG[i] doubleValue];
CLLocation* location = [[CLLocation alloc]initWithLatitude:latValue longitude:longValue];
[locationArray addObject:location];
}
NSArray* sortLocationArry = [locationArray sortedArrayUsingComparator:^NSComparisonResult(CLLocation* location1, CLLocation* location2) {
CLLocationDistance distA = [location1 distanceFromLocation:currentLocation];
CLLocationDistance distB = [location2 distanceFromLocation:currentLocation];
if (distA < distB) {
return (NSComparisonResult)NSOrderedAscending;
} else if ( distA > distB) {
return (NSComparisonResult)NSOrderedDescending;
} else {
return (NSComparisonResult)NSOrderedSame;
}
}];
To get sorted latitude and longitude,
[ALLINFOLAT removeAllObjects];
[ALLINFOLNG removeAllObjects];
[sortLocationArry enumerateObjectsUsingBlock:^(CLLocation* location, NSUInteger idx, BOOL *stop) {
[ALLINFOLAT addObject:#(location.coordinate.latitude)];
[ALLINFOLNG addObject:#(location.coordinate.longitude)];
}];

Answer 3

Following is the code for the sort by the location long/lati.
NSArray *orderedUsers = [users sortedArrayUsingComparator:^(id a,id b) {
User *userA = (User *)a;
User *userB = (User *)b;
CLLocationDistance distanceA = [userA.location getDistanceFromLocation:myLocation];
CLLocationDistance distanceB = [userB.location getDistanceFromLocation:myLocation];
if (distanceA < distanceB) {
return NSOrderedAscending
} else if (distanceA > distanceB) {
return NSOrderedDescending;
} else {
return NSOrderedSame;
}
}];
--------EDITED--------
Following code for just pass the value of your long/lati only.
NSArray *orderedUsers = [self.shopsArray sortedArrayUsingComparator: ^(double aLong, double bLong,double aLati, double bLati)
{
CLLocation *usersA = [[CLLocation alloc] initWithLatitude: aLati longitude: bLati];
CLLocation *usersB = [[CLLocation alloc] initWithLatitude: aLong longitude: bLong];
CLLocationDistance distA = [usersA distanceFromLocation:currentLocation];
CLLocationDistance distB = [usersB distanceFromLocation:currentLocation];
if (distA < distB) {
return (NSComparisonResult)NSOrderedAscending;
} else if ( distA > distB) {
return (NSComparisonResult)NSOrderedDescending;
} else {
return (NSComparisonResult)NSOrderedSame;
}
}];
May this help to you.