Question

In map view, i’m showing current user location. On click on the pin its showing “Current Location”. I want to change it to “My Current Location”. How can I change it.
Also I want to change the current user location pin color in a timer. Some thing like every one second it should change its color between green, purple and red. Possible to do it?

I’m using map kit’s show default location and then manipulating the annotation pin color as below:

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation{
static NSString *AnnotationViewID = @"annotationViewID";
SolarAnnotationView* annotationView = (SolarAnnotationView*)[map dequeueReusableAnnotationViewWithIdentifier:AnnotationViewID];
if(annotationView == nil)
{
    if([self CLLocationCoordinate2DEquals:mapView.userLocation.location.coordinate withSecondCoordinate:[annotation coordinate]]) //Show current location with green pin
    {
        annotationView = [[SolarAnnotationView alloc] initWithAnnotation:annotation];
        annotationView.delegate = self;
        [annotationView setPinColor:MKPinAnnotationColorGreen];
    }
    else
    {
        annotationView = [[SolarAnnotationView alloc] initWithAnnotation:annotation];
        annotationView.delegate = self;
    }
}   

return annotationView;

}

- (BOOL) CLLocationCoordinate2DEquals:(const CLLocationCoordinate2D)lhs withSecondCoordinate:(const CLLocationCoordinate2D) rhs{
const CLLocationDegrees DELTA = 0.001;
return fabs(lhs.latitude - rhs.latitude) <= DELTA && fabs(lhs.longitude - rhs.longitude) <= DELTA;

}

Answer 1

If you let the map view show the default annotation view for the user location (blue dot), this is simpler to implement (and you get a nice blue dot with cool animated zooming circle).

If you must show the user location using a pin image instead of a blue dot, then some more work is needed.

First, the simple way using the blue dot:

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation{
    if ([annotation isKindOfClass:[MKUserLocation class]])
    {
        ((MKUserLocation *)annotation).title = @"My Current Location";
        return nil;  //return nil to use default blue dot view
    }

    //Your existing code for viewForAnnotation here (with some corrections)...
    static NSString *AnnotationViewID = @"annotationViewID";
    SolarAnnotationView* annotationView = (SolarAnnotationView*)[map dequeueReusableAnnotationViewWithIdentifier:AnnotationViewID];
    if(annotationView == nil)
    {
        {
            annotationView = [[[SolarAnnotationView alloc] initWithAnnotation:annotation] autorelease];
            //added autorelease above to avoid memory leak
            annotationView.delegate = self;
        }
    }

    //update annotation in view in case we are re-using a view
    annotationView.annotation = annotation;

    return annotationView;
}

If you want to use your custom annotation view for the user location instead, you should put the pin color changing code in the custom view. One way to periodically change the color is using performSelector:withObject:afterDelay:. In the SolarAnnotationView.m, add these two methods:

-(void)startChangingPinColor
{
    switch (self.pinColor) {
        case MKPinAnnotationColorRed:
            self.pinColor = MKPinAnnotationColorGreen;
            break;
        case MKPinAnnotationColorGreen:
            self.pinColor = MKPinAnnotationColorPurple;
            break;
        default:
            self.pinColor = MKPinAnnotationColorRed;
            break;
    }
    [self performSelector:@selector(startChangingPinColor) withObject:nil afterDelay:1.0];
}

-(void)stopChangingPinColor
{
    [NSObject cancelPreviousPerformRequestsWithTarget:self];
}

Also add the method headers to the SolarAnnotationView.h file.

Then change the viewForAnnotation method like this:

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation{
    static NSString *AnnotationViewID = @"annotationViewID";
    SolarAnnotationView* annotationView = (SolarAnnotationView*)[map dequeueReusableAnnotationViewWithIdentifier:AnnotationViewID];
    if(annotationView == nil)
    {
        {
            annotationView = [[[SolarAnnotationView alloc] initWithAnnotation:annotation] autorelease];
            annotationView.delegate = self;
        }
    }

    //Update annotation in view in case we are re-using a view...
    annotationView.annotation = annotation;

    //Stop pin color changing in case we are re-using a view that has it on
    //and this annotation is not user location...
    [annotationView stopChangingPinColor];

    if([self CLLocationCoordinate2DEquals:mapView.userLocation.location.coordinate withSecondCoordinate:[annotation coordinate]]) //Show current location with green pin
    {
        [annotationView setPinColor:MKPinAnnotationColorGreen];
        annotationView.canShowCallout = YES;
        ((MKPointAnnotation *)annotation).title = @"My Current Location";
        [annotationView startChangingPinColor];
    }

    return annotationView;
}