将MapKit区域按钮动作转换为方法

Question

Apologies in advance for what must surely be so simple.

I want my map to zoom to a programmatically defined region surrounding the user's location. I've found tons of code where this is done via a button action, but I need it done automatically when the map loads. I'll post what I've tried here. Probably missing something very obvious. The meat of these both work as button actions, so I assume my issue is with my method code (first line of each).

Method 1: Using MKCoordinateSpanMake

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
    float spanX = 0.00725;
    float spanY = 0.00725;
    MKCoordinateRegion region;
    region.center.latitude = self.mapView.userLocation.coordinate.latitude;
    region.center.longitude = self.mapView.userLocation.coordinate.longitude;
    region.span = MKCoordinateSpanMake(spanX, spanY);
    [self.mapView setRegion:region animated:YES];

}

Method 2: Using MKCoordinateRegionMakeWithDistance

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
MKUserLocation *userLocation = _mapView.userLocation;
    MKCoordinateRegion region =
    MKCoordinateRegionMakeWithDistance (
                                        userLocation.location.coordinate, 3000, 3000);
    [_mapView setRegion:region animated:YES];
}

As always, thanks so much for your time and advice.

Answer 1

Move to viewDidLoad:

- (void)viewDidLoad
{
    MKUserLocation *userLocation = _mapView.userLocation;
    MKCoordinateRegion region =[_mapView regionThatFits:MKCoordinateRegionMakeWithDistance (userLocation.location.coordinate, 3000, 3000)];
    [_mapView setRegion:region animated:YES];
}

Hope that will help.