iPhone:根据位置排序

Question

我一直在开发一个 iPhone 应用程序，我在 NSMutableArray 中有用户列表，如下所示。

myMutableArray: (
    {
        FirstName = Getsy;
        LastName = marie;
        Latitude = "30.237314";
        Longitude = "-92.461008";
    },
    {
        FirstName = Angel;
        LastName = openza;
        Latitude = "30.260329";
        Longitude = "-92.450414";
    },
    {
        FirstName = Sara;
        LastName = Hetzel;
        Latitude = "30.2584499";
        Longitude = "-92.4135357";
    }
)

我需要通过计算纬度和经度，根据位置附近的位置对用户进行排序。到目前为止，我无法实现这一目标。有人可以帮我提供一些 sample 吗？

更新:我正在按照 Mr.sch 的建议进行尝试，如下所示。请检查我更新的代码。可以吗？

    NSArray *orderedUsers = [myMutableArray sortedArrayUsingComparator:^(id a,id b) {
    NSArray *userA = (NSArray *)a;
    NSArray *userB = (NSArray *)b;
    CGFloat aLatitude = [[userA valueForKey:@"Latitude"] floatValue];
    CGFloat aLongitude = [[userA valueForKey:@"Longitude"] floatValue];
    CLLocation *participantALocation = [[CLLocation alloc] initWithLatitude:aLatitude longitude:aLongitude];

    CGFloat bLatitude = [[userA valueForKey:@"Latitude"] floatValue];
    CGFloat bLongitude = [[userA valueForKey:@"Longitude"] floatValue];
    CLLocation *participantBLocation = [[CLLocation alloc] initWithLatitude:bLatitude longitude:bLongitude];

    CLLocation *myLocation = [[CLLocation alloc] initWithLatitude:locationCoordinates.latitude longitude:locationCoordinates.longitude];

    CLLocationDistance distanceA = [participantALocation distanceFromLocation:myLocation];
    CLLocationDistance distanceB = [participantBLocation distanceFromLocation:myLocation];
    if (distanceA < distanceB) {
        return NSOrderedAscending;
    } else if (distanceA > distanceB) {
        return NSOrderedDescending;
    } else {
        return NSOrderedSame;
    }
}];

谢谢!

Answer 1

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;
     }
}];