首先要在plist文件里添加两个键值对，向用户请求位置服务时会显示在这里设置的值的内容。

NSLocationWhenInUseUsageDescription
NSLocationAlwaysUsageDescription

屏幕快照 2016-07-06 15.54.05.png

导入头文件

#import <CoreLocation/CoreLocation.h>

把CLLocationManager设置为属性。
这里有一个坑点，如果不设置为属性，软件开启时提示定位的提示出现一瞬间就消失了。
被这个坑了一会儿，最后才发现是因为没有设置成属性的缘故。

@interface HomeViewController ()<CLLocationManagerDelegate>
@property (nonatomic, strong) CLLocationManager *locationManager;
@end

@implementation HomeViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self startLocation];
    // Do any additional setup after loading the view.
}

//开始定位
- (void)startLocation {
    if ([CLLocationManager locationServicesEnabled]) {
        //        CLog(@"--------开始定位");
        self.locationManager = [[CLLocationManager alloc]init];
        self.locationManager.delegate = self;
        //控制定位精度,越高耗电量越
        self.locationManager.desiredAccuracy = kCLLocationAccuracyKilometer;
        // 总是授权
        [self.locationManager requestAlwaysAuthorization];
        self.locationManager.distanceFilter = 10.0f;
        [self.locationManager requestAlwaysAuthorization];
        [self.locationManager startUpdatingLocation];
    }
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
    if ([error code] == kCLErrorDenied) {
        CLog(@"访问被拒绝");
    }
    if ([error code] == kCLErrorLocationUnknown) {
        CLog(@"无法获取位置信息");
    }
}
//定位代理经纬度回调
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations {
    CLLocation *newLocation = locations[0];

    // 获取当前所在的城市名
    CLGeocoder *geocoder = [[CLGeocoder alloc] init];
    //根据经纬度反向地理编译出地址信息
    [geocoder reverseGeocodeLocation:newLocation completionHandler:^(NSArray *array, NSError *error){
        if (array.count > 0){
            CLPlacemark *placemark = [array objectAtIndex:0];
            
            //获取城市
            NSString *city = placemark.locality;
            if (!city) {
                //四大直辖市的城市信息无法通过locality获得，只能通过获取省份的方法来获得（如果city为空，则可知为直辖市）
                city = placemark.administrativeArea;
            }
            NSLog(@"city = %@", city);
            
            [self httpGetWeather:city];
        }
        else if (error == nil && [array count] == 0)
        {
            NSLog(@"No results were returned.");
        }
        else if (error != nil)
        {
            NSLog(@"An error occurred = %@", error);
        }
    }];
    //系统会一直更新数据，直到选择停止更新，因为我们只需要获得一次经纬度即可，所以获取之后就停止更新
    [manager stopUpdatingLocation];
    
}