objc_msgSend crash：我怎样才能找到哪里？

Question

启用 nszombies 在此调试日志中是否有任何人可以看到的其他信息，我可以用它来查找问题？

(gdb) bt  
0  0x30b7eca4 in objc_msgSend ()  
1  0x36179302 in -[MKMapView annotationContainer:viewForAnnotation:] ()  
2  0x36178f94 in -[MKAnnotationContainerView _addViewForAnnotation:] ()  
3  0x361a2faa in -[MKAnnotationContainerView userLocationAnnotationWillShow] ()  
4  0x3619fcbe in -[MKMapView(UserPositioningInternal) _runPositioningChange] ()  
5  0x3619da8c in -[MKMapView(UserPositioningInternal) _startPositioningChange:] ()  
6  0x361a1050 in -[MKMapView(UserPositioningInternal) locationManagerUpdatedLocation:] ()  
7  0x365cff02 in -[NSObject(NSObject) performSelector:withObject:] ()  
8  0x3660d2f8 in -[NSArray makeObjectsPerformSelector:withObject:] ()  
9  0x36190808 in -[MKLocationManager _reportLocationStatus:] ()  
10 0x36191d72 in -[MKLocationManager _reportLocationSuccess] ()
11 0x361919cc in -[MKLocationManager locationManager:didUpdateToLocation:fromLocation:] ()  
12 0x33bfbc2c in -[CLLocationManager onClientEventLocation:] ()  
13 0x33bfbf48 in -[CLLocationManager onClientEvent:supportInfo:] ()  
14 0x33bfdd04 in OnClientEventInternal ()  
15 0x33bf57a2 in CLClientInvokeCallback ()  
16 0x33bf7c46 in CLClientHandleDaemonDataLocation ()  
17 0x33bf7d9c in CLClientHandleDaemonData ()  
18 0x3663070c in __CFMessagePortPerform ()    
19 0x36639a96 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()  
20 0x3663b83e in __CFRunLoopDoSource1 ()  
21 0x3663c60c in __CFRunLoopRun ()  
22 0x365ccec2 in CFRunLoopRunSpecific ()  
23 0x365ccdca in CFRunLoopRunInMode ()  
24 0x313c141e in GSEventRunModal ()  
25 0x313c14ca in GSEventRun ()  
26 0x33390d68 in -[UIApplication _run] ()  
27 0x3338e806 in UIApplicationMain ()  
28 0x000039ca in main (argc=1, argv=0x2fdff55c) at main.m:14    
(gdb) 

更新：

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation
{


 MKAnnotationView* annView = nil;

    if ( [annotation isKindOfClass: [AnnotationItem class]] )
    {
        MKPinAnnotationView* pin = (MKPinAnnotationView*)[mapView dequeueReusableAnnotationViewWithIdentifier: kListingAnnotationIdentifier];

        if ( nil == pin )
        {
            pin = [[[MKPinAnnotationView alloc] initWithAnnotation: annotation reuseIdentifier: kListingAnnotationIdentifier] autorelease];
        }
        else
        {
            [pin setAnnotation: annotation];
        }

        pin.canShowCallout = YES;

        pin.pinColor = MKPinAnnotationColorGreen;


        UIImage* img = [UIImage imageNamed: @"logap.png"] ;
        pin.leftCalloutAccessoryView = [[[UIImageView alloc] initWithImage: img] autorelease];


        pin.rightCalloutAccessoryView = [UIButton buttonWithType: UIButtonTypeDetailDisclosure];

        annView = pin;

    }
    return annView;



}

Answer 1

当地图视图尝试显示（更改）用户位置时，您的调试日志显示崩溃。用户位置是 MKUserLocation 类的注释，如果该注释被传递给您的 mapView:viewForAnnotation 实现，您的代码将返回一个指向 nil 的指针> （也就是说，它返回一个名为 annView 的 MKAnnotationView 对象，其值设置为 nil）。

因此，我怀疑当用户的位置出现或在屏幕上移动时，或者 nil 和“值设置为 的 MKAnnotationView 对象”之间的差异，您会崩溃。 nil”可能会在难以重现的时候突然对 Cocoa 产生重要影响。尝试测试注释是否属于 MKUserLocation 类，并在这种情况下显式返回 nil。