为什么在iPhone SDK 4.0中没有调用CLLocationManager委托？

Question

这是我在AppDelegate类中的代码

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    CLLocationManager *locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    locationManager.distanceFilter = 1000;  // 1 Km
    locationManager.desiredAccuracy = kCLLocationAccuracyKilometer;
    [locationManager startUpdatingLocation];
}

这是我在AppDelegate类中的委托方法

    //This is the delegate method for CoreLocation
- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation
{

        //printf("AppDelegate latitude %+.6f, longitude %+.6f\n", newLocation.coordinate.latitude, newLocation.coordinate.longitude);

}

它工作在3.0,3.1,3.1.3,但它不适用于4.0模拟器和设备.

是什么原因 ？

Answer 1

我有类似的错误,现在解决了.问题是在本地声明locationManager变量.将其声明为类变量,并确保直接或通过属性保留(如果使用ARC则保持强大).这解决了问题!问题是de locationManager变量已发布,并且从未更新过委托.这里的代码:

.h文件:

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>


@interface MapViewController : UIViewController <MKMapViewDelegate, CLLocationManagerDelegate> {
@private
    MKMapView *_mapView;
    CLLocationManager *_locationManager;
}

@property(nonatomic, strong) CLLocationManager *locationManager;

@end

.m文件:

self.locationManager = [[CLLocationManager alloc] init];
_locationManager.delegate = self;
_locationManager.desiredAccuracy = kCLLocationAccuracyBest;
[_locationManager startUpdatingLocation];

我希望它有所帮助.