两个点之间的距离与地图苹果

Question

您好我的应用中存在问题。我必须在地图上标记（苹果）并在点之后显示到达它的路径。我导入了mapKit.framework。我试过这样做，但它不起作用。

代码：

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIBarButtonItem *Information;

//按钮信息=打开其他页面

@property (weak, nonatomic) IBOutlet UIBarButtonItem *map_path;

// button map_path =点之间的距离

@property (weak, nonatomic) IBOutlet UIBarButtonItem *map_location; 

//按钮map_location =当前位置

@property (weak, nonatomic) IBOutlet MKMapView *mapView; 

// mapview的声明

@end

@implementation ViewController



- (void)viewDidLoad
{
    [super viewDidLoad];
    if ([self respondsToSelector:@selector(edgesForExtendedLayout)])

        self.edgesForExtendedLayout = UIRectEdgeNone;
 }

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];

}

- (MKAnnotationView *)mapView:(MKMapView *)newMapView viewForAnnotation:(id )newAnnotation {
    //replace the point with a picture
MKAnnotationView *a = [ [ MKAnnotationView alloc ] initWithAnnotation:newAnnotation reuseIdentifier:@"currentloc"];

    if ( a == nil )

        a = [ [ MKAnnotationView alloc ] initWithAnnotation:newAnnotation reuseIdentifier: @"currentloc" ];

    a.image = [ UIImage imageNamed:@"815-car@2x.png" ];

    a.canShowCallout = YES;

    a.rightCalloutAccessoryView = [ UIButton buttonWithType:UIButtonTypeDetailDisclosure ];

    UIImageView *imgView = [ [ UIImageView alloc ] initWithImage:[ UIImage imageNamed:@"815-car.png" ] ];

    a.leftCalloutAccessoryView = imgView;

    return a;
//via a button should calculate the distance from the point to the user
}
@end