cllocation and mkreversegeocoder

问题:

i'm try to retreiving city name with cllocation and mkreversegeocoder. in my viewdidload method i istance cllocationmanager:

self.locManager = [[CLLocationManager alloc] init];
locManager.delegate = self;
locManager.desiredAccuracy = kCLLocationAccuracyBest;
[locManager startUpdatingLocation];

and after:

- (void) locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation 
*)newLocation
fromLocation:(CLLocation *)oldLocation {
//some code to retrieve my information

MKReverseGeocoder *geoCoder = [[MKReverseGeocoder alloc]     
initWithCoordinate:newLocation.coordinate ];
geoCoder.delegate = self;
[geoCoder start];
}

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark  
*)placemark
{
MKPlacemark *myPlacemark = placemark;
citta.text = [placemark locality];
}

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error{
citta.text =@ "Unknow";

Application works only the first time i get my value. on the second time app crash. I think is because geocoder is started and i think i must have one and only one istance running. (but i'm really not shure of this...). in which way i can controll geocoder is running?

I've see that i can istance mkreversegeocoder in my viewdidload using cllocationcoordinate2d but ... in which way i can retreive newlocation.coordinate?

I've partially resolve declaring geocoder as class variable and checking

if (self.geocoder != nil) {
   [geocoder release];
}

but.... if in my

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark  
*)placemark

or in my

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailedWithError:(@NSError 
*)error

i release or cancel my object? I'm feeling so stupid :D

回答1:

Don't create the reverse geocoder as a local variable.

Look at the MKReverseGeocoder example in the CurrentAddress sample app provided by Apple. See MapViewController.h and MapViewController.m.

Follow the same pattern in your code.