CLLocation 调用委托方法

Question

我试图在切换到特定视图控制器 (FeedVC) 时获取用户位置，这是我目前拥有的代码：

FeedVC.h

#import <CoreLocation/CoreLocation.h>
@interface FeedVC : UIViewController <CLLocationManagerDelegate>

FeedVC.m

@implementation FeedVC
{
    CLLocationManager *locationManager;
    CLLocation *location;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    if (!locationManager)
        locationManager = [[CLLocationManager alloc] init];

    locationManager.delegate = self;
    locationManager.distanceFilter = kCLDistanceFilterNone;
    locationManager.desiredAccuracy = kCLLocationAccuracyKilometer;

    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)
        [locationManager requestWhenInUseAuthorization];

    [locationManager startUpdatingLocation];
}

-(void) locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    NSLog(@"did update locations");

    location = [locations lastObject];
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    NSLog(@"didFailWithError: %@", error);
}

-(void) viewWillAppear:(BOOL)animated
{
    NSLog(@"%.2f", location.coordinate.latitude);
}

方法 locationManager: didUpdateLocations: 没有被调用（因为 NSLog 没有显示）我已经按照这里的所有文档和其他答案，但我找不到问题的根源，谢谢！

Answer 1

不要在viewDidLoad中调用[locationManager startUpdatingLocation];，在委托方法中调用它：

-(void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status{
    if (status == kCLAuthorizationStatusAuthorizedWhenInUse) {
        [locationManager startUpdatingLocation];
    }
}

如果您还没有在您的 plist 中添加 NSLocationWhenInUseUsageDescription 添加它来描述您想要使用定位服务的原因

CLLocation 调用委托方法

CLLocation calling delegate methods

objective-c

core-location

ios