iPhone开发进阶（10）--- 在程序中使用GPS

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// LocationViewCtrl.h
#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
@interface LocationViewCtrl : UIViewController <CLLocationManagerDelegate>{
CLLocationManager *man;
}
@property(nonatomic, retain) CLLocationManager *man;
@end

LocationViewCtrl.m
#import "LocationViewCtrl.h"
#import <CoreLocation/CoreLocation.h>

@implementation LocationViewCtrl
@synthesize man;

- (void)viewDidLoad {
[super viewDidLoad];
man = [[CLLocationManager alloc] init];

// 如果可以利用本地服务时
if([man locationServicesEnabled]){
// 接收事件的实例
man.delegate = self;
// 发生事件的的最小距离间隔（缺省是不指定）
man.distanceFilter = kCLDistanceFilterNone;
// 精度 (缺省是Best)
man.desiredAccuracy = kCLLocationAccuracyBest;
// 开始测量
[man startUpdatingLocation];
}
}

// 如果GPS测量成果以下的函数被调用
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation{

// 取得经纬度
CLLocationCoordinate2D coordinate = newLocation.coordinate;
CLLocationDegrees latitude = coordinate.latitude;
CLLocationDegrees longitude = coordinate.longitude;
// 取得精度
CLLocationAccuracy horizontal = newLocation.horizontalAccuracy;
CLLocationAccuracy vertical = newLocation.verticalAccuracy;
// 取得高度
CLLocationDistance altitude = newLocation.altitude;
// 取得时刻
NSDate *timestamp = [newLocation timestamp];

// 以下面的格式输出 format: <latitude>, <longitude>> +/- <accuracy>m @ <date-time>
NSLog([newLocation description]);

// 与上次测量地点的间隔距离
if(oldLocation != nil){
CLLocationDistance d = [newLocation getDistanceFrom:oldLocation];
NSLog([NSString stringWithFormat:@"%f", d]);
}
}

// 如果GPS测量失败了，下面的函数被调用
- (void)locationManager:(CLLocationManager *)manager
didFailWithError:(NSError *)error{
NSLog([error localizedDescription]);
}
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