XCode的MapView (2)

如何在地圖上長按著某個位置不放，然後自動在長按的位置加入指針？

1. 首先在viewDidLoad中為我們的mapview加入長按功能UILongPressGestureRecognizer。並於長按後自動執行longPress這個method.
   
   - (void)viewDidLoad

   {

       [super viewDidLoad];

       UILongPressGestureRecognizer *lpress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];

       lpress.minimumPressDuration = 0.5;

       lpress.allowableMovement = 10.0;

       [mapview addGestureRecognizer:lpress];

   }
2. 我們在longPress中取得我們在mapview長按的位置，存入touchPoint，再使用touchPoint來建立位置touchMapCoordinate。然後建立指針pointAnnotation，並將剛才建立的位置touchMapCoordinate加入到指針中，最後將指針加入到mapview.
   
   - (void)longPress:(UIGestureRecognizer*)gestureRecognizer

   {

       if (gestureRecognizer.state == UIGestureRecognizerStateEnded){

           return;

       }

       

       CGPoint touchPoint = [gestureRecognizer locationInView:mapview];

       CLLocationCoordinate2D touchMapCoordinate =

       [mapview convertPoint:touchPoint toCoordinateFromView:mapview];

       

       MKPointAnnotation *pointAnnotation = nil;

       pointAnnotation = [[MKPointAnnotation alloc] init];

       pointAnnotation.coordinate = touchMapCoordinate;

       pointAnnotation.title = @"title";

       pointAnnotation.subtitle=@"subtitle";

       

       [mapview addAnnotation:pointAnnotation];

   }

如何取得我們現時身處的位置。

1. 啟動showsUserLocation，即可使用userLocation取得即時的位置。
   
   -(IBAction)goUserLocation:(id)sender

   {

   mapView.showsUserLocation = YES;

     CLLocationCoordinate2D userLoc;

   
   

   userLoc.latitude = mapView.userLocation.location.coordinate.latitude;

   userLoc.longitude = mapView.userLocation.location.coordinate.longitude;

   mapView.region = MKCoordinateRegionMakeWithDistance(userLoc, 50000, 50000);

   }