如何在不使用didAddAnnotationViews的情况下缩小MKMapView

Question

我正试图找到一种通过按钮进行放大和缩小的方法。如果我把代码放在方法didAddAnnotationViews中，它将完美地设置初始缩放。我试图用下面的代码更改缩放，但它不断崩溃，说：

无法识别的选择器发送到实例

如何在IBAction中运行此操作？

-(IBAction)ZoomIn:(MKCoordinateSpan)coordinateSpanWithMapView:(MKMapView *)mv centerCoordinate:(CLLocationCoordinate2D)location
{
   MKCoordinateRegion region;
   MKCoordinateSpan span; 
   span.latitudeDelta=0.05;
   span.longitudeDelta=0.05;
   location = mv.userLocation.coordinate;
   location = mv.userLocation.location.coordinate;
   region.span=span;
   region.center=location;
   [mv setRegion:region animated:TRUE];
   [mv regionThatFits:region]; 
};

Answer 1

我的问题是，我试图在MapView的IBAction行中传递，但我做不到。它不知道该怎么办。我在代码中引用了我的MapView，而不是试图在方法中传递它。。。

CLLocationCoordinate2D location;
MKCoordinateRegion region;
MKCoordinateSpan span; 
span.latitudeDelta=1.00;
span.longitudeDelta=1.00;
location = self.myMap.userLocation.coordinate;
location = self.myMap.userLocation.location.coordinate;
region.span=span;
region.center=location;
[self.LightUpMap setRegion:region animated:TRUE];
[self.LightUpMap regionThatFits:region];

你现在可以放这是任何IBAction方法，它会放大到地图上。

Answer 2

-(void)zoomOut:btnMinus
{
  MKCoordinateSpan span = mapView.region.span;
  span.latitudeDelta = span.latitudeDelta * 2;
  span.longitudeDelta = span.longitudeDelta * 2;
  region.span=span;
  [mapView setRegion:region animated:YES];
  for(int j=2;j<count;j++)
  { places[j]=1;}
  [self filterAnnotations];  
}