首先要在plist文件里添加兩個鍵值對，向用戶請求位置服務時會顯示在這里設置的值的內容。

NSLocationWhenInUseUsageDescription
NSLocationAlwaysUsageDescription

屏幕快照 2016-07-06 15.54.05.png

導入頭文件

#import <CoreLocation/CoreLocation.h>

把CLLocationManager設置為屬性。
這里有一個坑點，如果不設置為屬性，軟件開啟時提示定位的提示出現一瞬間就消失了。
被這個坑了一會兒，最后才發現是因為沒有設置成屬性的緣故。

@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.
}

//開始定位
- (void)startLocation {
    if ([CLLocationManager locationServicesEnabled]) {
        //        CLog(@"--------開始定位");
        self.locationManager = [[CLLocationManager alloc]init];
        self.locationManager.delegate = self;
        //控制定位精度,越高耗電量越
        self.locationManager.desiredAccuracy = kCLLocationAccuracyKilometer;
        // 總是授權
        [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(@"訪問被拒絕");
    }
    if ([error code] == kCLErrorLocationUnknown) {
        CLog(@"無法獲取位置信息");
    }
}
//定位代理經緯度回調
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations {
    CLLocation *newLocation = locations[0];

    // 獲取當前所在的城市名
    CLGeocoder *geocoder = [[CLGeocoder alloc] init];
    //根據經緯度反向地理編譯出地址信息
    [geocoder reverseGeocodeLocation:newLocation completionHandler:^(NSArray *array, NSError *error){
        if (array.count > 0){
            CLPlacemark *placemark = [array objectAtIndex:0];
            
            //獲取城市
            NSString *city = placemark.locality;
            if (!city) {
                //四大直轄市的城市信息無法通過locality獲得，只能通過獲取省份的方法來獲得（如果city為空，則可知為直轄市）
                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);
        }
    }];
    //系統會一直更新數據，直到選擇停止更新，因為我們只需要獲得一次經緯度即可，所以獲取之后就停止更新
    [manager stopUpdatingLocation];
    
}