我试图在标签（位于 TableViewController 上）中显示从用户当前位置到其他地图视图注释（从我的 MapViewController 中提取）的距离，但由于某种原因，当我通过模拟器运行时，计算出的距离标签显示为 0.0000 ? 即使在我自定义了我的“当前位置”之后。关于为什么的任何想法？
MapViewController.h
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
@interface MapViewController : UIViewController <MKMapViewDelegate>
@property (nonatomic, strong) IBOutlet MKMapView *mapView;
@property (nonatomic, retain) NSMutableArray *dispensaries;
@property (nonatomic, retain) NSMutableData *data;
@end
MapViewController.m
[super viewDidUnload];
NSLog(@"Getting Device Locations");
NSString *hostStr = @"http://stylerepublicmagazine.com/dispensaries.php";
NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:hostStr]];
NSString *serverOutput = [[NSString alloc] initWithData:dataURL encoding: NSASCIIStringEncoding];
NSLog(@"server output: %@", serverOutput);
NSMutableArray *array = [[[serverOutput objectFromJSONString] mutableCopy] autorelease];
dispensaries = [serverOutput objectFromJSONString];
NSLog(@"%@", [serverOutput objectFromJSONString]);
for (NSDictionary *dictionary in array) {
assert([dictionary respondsToSelector:@selector(objectForKey:)]);
CLLocationCoordinate2D coord = {[[dictionary objectForKey:@"lat"] doubleValue], [[dictionary objectForKey:@"lng"] doubleValue]};
MapViewAnnotation *ann = [[MapViewAnnotation alloc] init];
ann.title = [dictionary objectForKey:@"Name"];
ann.subtitle = [dictionary objectForKey:@"Address1"];
ann.coordinate = coord;
[mapView addAnnotation:ann];
[mapView setMapType:MKMapTypeStandard];
[mapView setZoomEnabled:YES];
[mapView setScrollEnabled:YES];
self.mapView.delegate = self;
}
}
- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(userLocation.coordinate, 2000, 2000);
[self.mapView setRegion:[self.mapView regionThatFits:region] animated:YES];
MKPointAnnotation *point = [[MKPointAnnotation alloc] init];
point.coordinate = userLocation.coordinate;
point.title = @"You Are Here";
point.subtitle = @"Your current location";
[self.mapView addAnnotation:point];
}
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
for (MapViewAnnotation *annotation in self.mapView.annotations) {
CLLocationCoordinate2D coord = [annotation coordinate];
CLLocation *userLocation = [[CLLocation alloc] initWithLatitude:coord.latitude longitude:coord.longitude];
annotation.distance = [newLocation distanceFromLocation:userLocation];
CLLocationDistance calculatedDistance = [userLocation distanceFromLocation:userLocation];
annotation.distance = calculatedDistance;
}
NSArray *sortedArray;
sortedArray = [self.mapView.annotations sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
NSNumber *first = [NSNumber numberWithDouble:[(MapViewAnnotation*)a distance]];
NSNumber *second = [NSNumber numberWithDouble:[(MapViewAnnotation*)b distance]];
return [first compare:second];
}];
}
表视图控制器.h
#import <UIKit/UIKit.h>
#import "MapViewController.h"
@interface TableViewController : UITableViewController {
IBOutlet UITableView *DispensaryTableView;
NSArray *dispensaries;
NSMutableData *data;
}
@property CLLocationDistance calculatedDistance;
@end
表视图控制器.m
[super viewDidLoad];
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
NSURL *url = [NSURL URLWithString:@"http://stylerepublicmagazine.com/dispensaries.php"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
data = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData
{
[data appendData:theData];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
dispensaries = [NSJSONSerialization JSONObjectWithData:data options:nil error:nil];
[DispensaryTableView reloadData];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
UIAlertView *errorView = [[UIAlertView alloc] initWithTitle:@"Error" message:@"The download could not complete - please make sure that you're connected to 3G or Wi-Fi." delegate:nil
cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
[errorView show];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
- (int)numberOfSectionsInTableView: (UITableView *)tableview
{
return 1;
}
- (int)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [dispensaries count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *DispensaryTableIdentifier = @"DispensaryCell";
DispensaryCell *cell = (DispensaryCell *)[tableView dequeueReusableCellWithIdentifier:DispensaryTableIdentifier];
if (cell == nil)
{
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"DispensaryCell" owner:self options:nil];
cell = [nib objectAtIndex:0];
}
cell.nameLabel.text = [[dispensaries objectAtIndex:indexPath.row] objectForKey:@"Name"];
cell.distanceLabel.text = [NSString stringWithFormat:@"%f", calculatedDistance];
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
}