'Current location' BUTTON replica of the maps in iPhone - iphone

Question

- (void)mapView:(MKMapView *)mv didAddAnnotationViews:(NSArray *)views {
for(MKAnnotationView *annotationView in views) {
if(annotationView.annotation == mv.userLocation) {
MKCoordinateRegion region;
MKCoordinateSpan span;
span.latitudeDelta=0.002;
span.longitudeDelta=0.002;
CLLocationCoordinate2D location=mv.userLocation.coordinate;
region.span=span;
region.center=location;
[mv setRegion:region animated:TRUE];
[mv regionThatFits:region];
}
}
Hello all. I have tried searching other posts and websites. In essence I want to duplicate the 'Current location' BUTTON.
Using the above code, I was able to zoom into the users current location. This however is not flawless, sometimes the GPS updates a little late or thinks I am somewhere else, zooms to that location but then the blue dot will shift somewhere off screen to where I really am.
I was wondering is there a way I can add a 'Button', exactly like maps on the iphone. It doesn't need to gain a new zoom etc, simply move to the new updated locaiton. My main source of code would be almost replica to here.
I appreciate any help.

Answer 1

Create a custom annotation with the same graphic. This object must implement MKAnnotationView, and you have to return the custom view for it in the method mapView:viewForAnnotation: of the MKMapViewDelegate. If you want the exact graphic, use the project UIKit-Artwork-Extractor to get it.
Save a reference to the annotation view, subscribe to core location updates, and update the position calling something like:
- (void) animateView:(UIView *)view toPosition:(NSValue*)value
{
CGPoint newCenter = [value CGPointValue];
[UIView animateWithDuration:0.5
animations:^{
view.center = newCenter;
}
completion:^(BOOL finished){ }];
}
Then set the center of the map on the annotation:
- (void)centerMap:(CLLocation *)location {
MKCoordinateRegion region = { { 0.0f, 0.0f }, { 0.0f, 0.0f } };
region.center = location.coordinate;
region.span.longitudeDelta = 0.15f;
region.span.latitudeDelta = 0.15f;
[self.mapView setRegion:region animated:YES];
}