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 *)manager
didUpdateToLocation:(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 below
static 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 object
self.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 coordinates
if (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 update
if (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/