ios - didUpdateHeading 未调用

Question

我想用罗盘来更新航向。但是我的 didUpdateHeading 没有调用。我是 iOS 的新手。请帮助任何帮助将不胜感激。

@interface ViewController : UIViewController<CLLocationManagerDelegate>
@property (nonatomic, retain) CLLocationManager     *locationManager;
locationManager=[[CLLocationManager alloc] init];
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    locationManager.delegate=self;
    //Start the compass updates.

    [locationManager startUpdatingHeading];

- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
    NSLog(@"New magnetic heading: %f", newHeading.magneticHeading);
    NSLog(@"New true heading: %f", newHeading.trueHeading);
}

Answer 1

您提供的代码(假设您在粘贴此处时没有更改任何内容)缺少运行第一部分的函数或代码块，我建议您将其放在 viewController init 中，像这样:

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {        
         locationManager=[[CLLocationManager alloc] init];
         locationManager.desiredAccuracy = kCLLocationAccuracyBest;
         locationManager.delegate=self;
         //Start the compass updates.

         [locationManager startUpdatingHeading];
    }
    return self;
}