Question

我有一个用例，应用程序将自动尝试检索位置，用户可以拒绝该权限，然后用户可以触发应用程序再次查找该位置（这次允许它），然后应用程序会崩溃。下面是基本代码和用例步骤，我做错了什么？

@interface AppViewController : UIViewController <CLLocationManagerDelegate>{  
    CLLocationManager *locationManager;
}
@property (retain,nonatomic) CLLocationManager *locationManager; 

//... method declaration

@end

@implementation AppViewController
@synthesize locationManager; 

-(void)MethodThatAutomaticallyGetsLocation{ 
     [self FindLocation]; 
}
-(IBAction)UserTriggerToGetLocation{ 
     [self FindLocation]; 
} 

-(void)FindLocation{ 
     locationManager = [[CLLocationManager alloc] init]; 
     locationManager.delegate = self; 
     [locationManager startUpdatingLocation]; 
} 
-(void)locationManager:(CLLocationManager *)manager
   didUpdateToLocation:(CLLocation *)newLocation
          fromLocation:(CLLocation *)oldLocation{

      // ... do some stuff
      // ... save location info to core data object

      [locationManager stopUpdatingLocation]; 
      locationManager.delegate = nil; 
      [locationManager release]; 

}
-(void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error{ 

      // ... conditionally display error message 
      //     based on type and app state

      [locationManager stopUpdatingLocation]; 
      locationManager.delegate = nil; 
      [locationManager release]; 
} 

- (void)dealloc {
     // locationManager not released here, its released above
}
@end

应用加载视图，消息MethodThatAutomaticallyGetsLocation
FindLocation被调用来设置locationManager
电话要求分享位置的权限
用户拒绝许可
locationManager:didFailWithError被调用，发布locationManager
用户与用户界面互动，触发调用(IBAction) UserTriggerToGetLocation

FindLocation

电话再次请求权限，此时用户允许
locationManager:didUpdateToLocation:fromLocation做其事

当调用locationManager:didUpdateToLocation:fromLocation时，应用程序在[locationManager release]内崩溃。具体来说，我得到的EXC_BAD_ACCESS暗示locationManager已被释放？但在哪里？

我做错了什么？

Answer 1

Guh，没关系。我认为我我在dealloc之前发布错误但我也意识到我不需要在此之前发布。只需在其响应处理程序中停止locationManager，我就可以通过将UserTriggerToGetLocation更改为再次调用[locationManager startUpdatingLocation] NOT FindLocation来重新启动它。

CLLocationManager初始化，释放，初始化然后释放导致崩溃？

1 个答案: