CLLocationManager用法示例

MyCLController.h

#import <CoreLocation/CoreLocation.h>// This is hoping that in the future (beyond SDK 2.0) we can access SystemConfiguration info#import <SystemConfiguration/SCNetworkConnection.h>// This protocol is used to send the info for location updates back to another view controller@protocol MyCLControllerDelegate <NSObject>@required-(void)gpsUpdate:(CLLocation *)aLoc;@end// Class definition@interface MyCLController : NSObject <CLLocationManagerDelegate> {CLLocationManager *locationManager;CLLocation *myCurrentLoc;BOOL findShouldStop;id delegate;}@property (nonatomic, retain) CLLocationManager *locationManager;@property (nonatomic,assign) id <MyCLControllerDelegate> delegate;@property (nonatomic, assign) CLLocation *myCurrentLoc;- (void)locationManager:(CLLocationManager *)managerdidUpdateToLocation:(CLLocation *)newLocation   fromLocation:(CLLocation *)oldLocation;- (void)locationManager:(CLLocationManager *)manager   didFailWithError:(NSError *)error;+ (MyCLController *)sharedInstance;@end

MyCLController.m

#import "MyCLController.h"// This is a singleton class, see belowstatic MyCLController *sharedCLDelegate = nil;@implementation MyCLController@synthesize delegate, locationManager, myCurrentLoc;- (id) init {self = [super init];if (self != nil) {self.locationManager = [[CLLocationManager alloc] init];self.locationManager.delegate = self; // Tells the location manager to send updates to this objectself.myCurrentLoc = [[CLLocation alloc] initWithLatitude:0 longitude:0];[self.locationManager startUpdatingLocation];}return self;}// Called when the location is updated- (void)locationManager:(CLLocationManager *)manager    didUpdateToLocation:(CLLocation *)newLocation           fromLocation:(CLLocation *)oldLocation{// Horizontal coordinatesif (signbit(newLocation.horizontalAccuracy)) {// Negative accuracy means an invalid or unavailable measurement[self.delegate gpsUpdate:nil];return;}    //// Altitude (we don't care about it)//if (signbit(newLocation.verticalAccuracy)) {//// Negative accuracy means an invalid or unavailable measurement//}    // Check the timestamp, see if it's an hour old or more. If so, don't send an updateif (ABS([newLocation.timestamp timeIntervalSinceNow]) > 3600) {[self.delegate gpsUpdate:nil];return;}[myCurrentLoc release];    myCurrentLoc = [newLocation copy]; // TODO: Why does this increment the retain count? We should be manually retaining// Looks like the loc is good[self.delegate gpsUpdate:myCurrentLoc];return;}// Called when there is an error getting the location// TODO: Update this function to return the proper info in the proper UI fields- (void)locationManager:(CLLocationManager *)manager       didFailWithError:(NSError *)error{NSMutableString *errorString = [[[NSMutableString alloc] init] autorelease];BOOL shouldQuit;    if ([error domain] == kCLErrorDomain) {        // We handle CoreLocation-related errors here        switch ([error code]) {                // This error code is usually returned whenever user taps "Don't Allow" in response to                // being told your app wants to access the current location. Once this happens, you cannot                // attempt to get the location again until the app has quit and relaunched.                //                // "Don't Allow" on two successive app launches is the same as saying "never allow". The user                // can reset this for all apps by going to Settings > General > Reset > Reset Location Warnings.                //case kCLErrorDenied:[errorString appendFormat:@"%@\n", NSLocalizedString(@"LocationDenied", nil)];[errorString appendFormat:@"%@\n", NSLocalizedString(@"AppWillQuit", nil)];shouldQuit = YES;break;                                // This error code is usually returned whenever the device has no data or WiFi connectivity,                // or when the location cannot be determined for some other reason.                //                // CoreLocation will keep trying, so you can keep waiting, or prompt the user.                //case kCLErrorLocationUnknown:[errorString appendFormat:@"%@\n", NSLocalizedString(@"LocationUnknown", nil)];[errorString appendFormat:@"%@\n", NSLocalizedString(@"AppWillQuit", nil)];shouldQuit = YES;break;                                // We shouldn't ever get an unknown error code, but just in case...                //default:[errorString appendFormat:@"%@ %d\n", NSLocalizedString(@"GenericLocationError", nil), [error code]];shouldQuit = NO;break;}} else {// We handle all non-CoreLocation errors here// (we depend on localizedDescription for localization)[errorString appendFormat:@"Error domain: \"%@\"  Error code: %d\n", [error domain], [error code]];[errorString appendFormat:@"Description: \"%@\"\n", [error localizedDescription]];shouldQuit = NO;}    // TODO: Send the delegate the alert?if (shouldQuit) {// do nothing}}#pragma mark ---- singleton object methods ----// See "Creating a Singleton Instance" in the Cocoa Fundamentals Guide for more info+ (MyCLController *)sharedInstance {    @synchronized(self) {        if (sharedCLDelegate == nil) {            [[self alloc] init]; // assignment not done here        }    }    return sharedCLDelegate;}+ (id)allocWithZone:(NSZone *)zone {    @synchronized(self) {        if (sharedCLDelegate == nil) {            sharedCLDelegate = [super allocWithZone:zone];            return sharedCLDelegate;  // assignment and return on first allocation        }    }    return nil; // on subsequent allocation attempts return nil}- (id)copyWithZone:(NSZone *)zone{    return self;}- (id)retain {    return self;}- (unsigned)retainCount {    return UINT_MAX;  // denotes an object that cannot be released}- (void)release {    //do nothing}- (id)autorelease {    return self;}@end

在用MKReverseGeocoder的时候是不是经常crash呀，那是因为在同一时刻只能存在一个MKReverseGeocoder实例。

参考资料：

http://evilrockhopper.com/2010/01/iphone-development-reverse-geocoding/

http://www.iphonedevsdk.com/forum/iphone-sdk-development/31883-pbrequestererrordomain-errors-reverse-geocoding.html