ios之Core Location定位功能

1、需要遵循CLLocationManagerDelegate协议，该协议有两个方法

- (void)locationManager:(CLLocationManager *)manager 
    didUpdateToLocation:(CLLocation *)newLocation 
     fromLocation:(CLLocation *)oldLocation；//当位置管理器应经确定当前位置或者当他检测到未知的更改时调用该方法

- (void)locationManager:(CLLocationManager *)manager 
       didFailWithError:(NSError *)error ；//当位置管理器遇到错误时调用该方法

2、Core Location定位功能的步骤

1）、创建位置管理器

2）、设置委托

3）、设置需要的精度

4）、设置距离筛选器 //可选,  修改distanceFilter

5）、启动位置管理器

、h文件

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>


@interface WhereAmIViewController :
UIViewController <CLLocationManagerDelegate> {
    CLLocationManager    *locationManager;
    
    CLLocation           *startingPoint;
    
    UILabel *latitudeLabel;
    UILabel *longitudeLabel;
    UILabel *horizontalAccuracyLabel;
    UILabel *altitudeLabel;
    UILabel *verticalAccuracyLabel;
    UILabel *distanceTraveledLabel;
}
@property (retain, nonatomic) CLLocationManager *locationManager;
@property (retain, nonatomic) CLLocation *startingPoint;
@property (retain, nonatomic) IBOutlet UILabel *latitudeLabel;
@property (retain, nonatomic) IBOutlet UILabel *longitudeLabel;
@property (retain, nonatomic) IBOutlet UILabel *horizontalAccuracyLabel;
@property (retain, nonatomic) IBOutlet UILabel *altitudeLabel;
@property (retain, nonatomic) IBOutlet UILabel *verticalAccuracyLabel;
@property (retain, nonatomic) IBOutlet UILabel *distanceTraveledLabel;
@end

、m文件

#import "WhereAmIViewController.h"


@implementation WhereAmIViewController
@synthesize locationManager;
@synthesize startingPoint;
@synthesize latitudeLabel;
@synthesize longitudeLabel;
@synthesize horizontalAccuracyLabel;
@synthesize altitudeLabel;
@synthesize verticalAccuracyLabel;
@synthesize distanceTraveledLabel;


#pragma mark -
- (void)viewDidLoad {
    self.locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    [locationManager startUpdatingLocation];
}


- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
    self.locationManager = nil;
    self.latitudeLabel = nil;
    self.longitudeLabel = nil;
    self.horizontalAccuracyLabel = nil;
    self.altitudeLabel = nil;
    self.verticalAccuracyLabel = nil;
    self.distanceTraveledLabel = nil;
    [super viewDidUnload];
}


- (void)dealloc {
    [locationManager release];
    [startingPoint release];
    [latitudeLabel release];
    [longitudeLabel release];
    [horizontalAccuracyLabel release];
    [altitudeLabel release];
    [verticalAccuracyLabel release];
    [distanceTraveledLabel release];    
    [super dealloc];
}
#pragma mark -
#pragma mark CLLocationManagerDelegate Methods
- (void)locationManager:(CLLocationManager *)manager 
    didUpdateToLocation:(CLLocation *)newLocation 
           fromLocation:(CLLocation *)oldLocation {
    
    if (startingPoint == nil)
        self.startingPoint = newLocation;
    
    NSString *latitudeString = [[NSString alloc] initWithFormat:@"%g°", 
                                newLocation.coordinate.latitude];
    latitudeLabel.text = latitudeString;
    [latitudeString release];
    
    NSString *longitudeString = [[NSString alloc] initWithFormat:@"%g°", 
                                 newLocation.coordinate.longitude];
    longitudeLabel.text = longitudeString;
    [longitudeString release];
    
    NSString *horizontalAccuracyString = [[NSString alloc]
                                          initWithFormat:@"%gm", 
                                          newLocation.horizontalAccuracy];
    horizontalAccuracyLabel.text = horizontalAccuracyString;
    [horizontalAccuracyString release];
    
    NSString *altitudeString = [[NSString alloc] initWithFormat:@"%gm", 
                                newLocation.altitude];
    altitudeLabel.text = altitudeString;
    [altitudeString release];
    
    NSString *verticalAccuracyString = [[NSString alloc]
                                        initWithFormat:@"%gm", 
                                        newLocation.verticalAccuracy];
    verticalAccuracyLabel.text = verticalAccuracyString;
    [verticalAccuracyString release];
    
    CLLocationDistance distance = [newLocation
                                   getDistanceFrom:startingPoint];
    NSString *distanceString = [[NSString alloc]
                                initWithFormat:@"%gm", distance];
    distanceTraveledLabel.text = distanceString;
    [distanceString release];
}


- (void)locationManager:(CLLocationManager *)manager 
       didFailWithError:(NSError *)error {
    
    NSString *errorType = (error.code == kCLErrorDenied) ? 
    @"Access Denied" : @"Unknown Error";
    UIAlertView *alert = [[UIAlertView alloc] 
                          initWithTitle:@"Error getting Location" 
                          message:errorType 
                          delegate:nil 
                          cancelButtonTitle:@"Okay" 
                          otherButtonTitles:nil];
    [alert show];
    [alert release];
    
}
@end