疯狂ios讲义之使用CoreLocation定位（2）

@interface FKViewController () <CLLocationManagerDelegate>
@property (strong,nonatomic)CLLocationManager *locationManager;
@end
@implementation FKViewController
- (void)viewDidLoad
{  
    [super viewDidLoad];
    // 创建CLLocationManager对象
    self.locationManager = [[CLLocationManager alloc]init];
}
- (IBAction)bnTapped:(id)sender
{
    // 如果定位服务可用
    if([CLLocationManager locationServicesEnabled])
    {
        NSLog( @"开始执行定位服务" );
        // 设置定位精度最佳精度
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        // 设置距离过滤器为50米表示每移动50米更新一次位置
        self.locationManager.distanceFilter = 50;
        // 将视图控制器自身设置为CLLocationManager的delegate
        // 因此该视图控制器需要实现CLLocationManagerDelegate协议
        self.locationManager.delegate = self;
        // 开始监听定位信息
        [self.locationManager startUpdatingLocation];
    }
    else
    {
        NSLog( @"无法使用定位服务" );
    }
}
// 成功获取定位数据后将会激发该方法
-(void)locationManager:(CLLocationManager *)manager
    didUpdateLocations:(NSArray *)locations
{
    // 获取最后一个定位数据
    CLLocation* location = [locations lastObject];
    // 依次获取CLLocation中封装的经度、纬度、高度、速度、方向等信息
    self.latitudeTxt.text = [NSString stringWithFormat:@"%g",
        location.coordinate.latitude];
    self.longitudeTxt.text = [NSString stringWithFormat:@"%g",
        location.coordinate.longitude];
    self.altitudeTxt.text = [NSString stringWithFormat:@"%g",
        location.altitude];
    self.speedTxt.text = [NSString stringWithFormat:@"%g",
        location.speed];
    self.courseTxt.text = [NSString stringWithFormat:@"%g",
        location.course];
}
// 定位失败时激发的方法
- (void)locationManager:(CLLocationManager *)manager
    didFailWithError:(NSError *)error
{
    NSLog(@"定位失败: %@",error);
}
@end

#import "FKViewController.h"
#import <CoreLocation/CoreLocation.h>
@interface FKViewController () <CLLocationManagerDelegate>
@property (nonatomic , retain) CLLocationManager *locationManager;
@property (nonatomic , retain) CLLocation *prevLocation;
@property (nonatomic , assign) CGFloat sumDistance;
@property (nonatomic , assign) CGFloat sumTime;
@end
@implementation FKViewController
- (void) viewDidLoad
{
    [super viewDidLoad];
    // 创建CLLocationManager对象
    self.locationManager = [[CLLocationManager alloc] init];
}
- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    // 设置定位精度最佳精度
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    // 设置距离过滤器为50米表示每移动50米更新一次位置
    self.locationManager.distanceFilter = 50;
    // 将视图控制器自身设置为CLLocationManager的delegate
    // 因此该视图控制器需要实现CLLocationManagerDelegate协议
    self.locationManager.delegate = self;
    // 开始监听定位信息
    [self.locationManager startUpdatingLocation];
    NSLog(@"开始执行定位服务" );
}
// 定位失败时激发的方法
- (void)locationManager:(CLLocationManager *)manager
    didFailWithError:(NSError *)error
{
    NSLog(@"定位失败: %@",error);
}
// 成功获取定位数据后将会激发该方法
-(void)locationManager:(CLLocationManager *)manager
    didUpdateLocations:(NSArray *)locations
{
    // 获取最后一个定位数据
    CLLocation* newLocation = [locations lastObject];
    if(newLocation.horizontalAccuracy < kCLLocationAccuracyHundredMeters)
    {
        if(self.prevLocation)
        {
            // 计算本次定位数据与上次定位数据之间的时间差
            NSTimeInterval dTime = [newLocation.timestamp
                timeIntervalSinceDate:self.prevLocation.timestamp];
            // 累计行车时间
            self.sumTime += dTime;
            // 计算本次定位数据与上次定位数据之间的距离
            CGFloat distance = [newLocation
                distanceFromLocation:self.prevLocation];
            // 如果距离小于1米则忽略本次数据直接返回该方法
            if(distance < 1.0f)
            {
                return;
            }
            // 累加移动距离
            self.sumDistance += distance;
            // 计算移动速度将米/秒换算成千米/小时需要乘以3.6
            CGFloat speed = distance / dTime * 3.6;
            // 计算平均速度
            CGFloat avgSpeed = self.sumDistance / self.sumTime * 3.6;
            NSString * speedFeedback = [NSString stringWithFormat:
                @"当前速度为%g千米/小时平均速度为:%g千米/小时。合计移动:%g千米",
                speed , avgSpeed , self.sumDistance / 1000];
            self.showView.text = speedFeedback;
        }
        self.prevLocation = newLocation;
    }
}
@end