Uncaught exception: CALayer position contains NaN when doing animation

Question

I am getting this error in my application when I run on an iPad:

Uncaught exception: CALayer position contains NaN

The same code works fine on an iPhone.

- (void)mapView:(MKMapView *)mapView didAddAnnotationViews:(NSArray *)views
{
    AnnotationView *aV;

    for (aV in views) {
        // Don't pin drop if annotation is user location
        if ([aV.annotation isKindOfClass:[MKUserLocation class]]) {
            continue;
        }

        // Check if current annotation is inside visible map rect, else go to next one
        MKMapPoint point =  MKMapPointForCoordinate(aV.annotation.coordinate);
        if (!MKMapRectContainsPoint(mapViewResult.visibleMapRect, point)) {
            continue;
        }

        CGRect endFrame = aV.frame;

        // Move annotation out of view
        // I checked here, CGRectEmpty returns true here

        aV.frame = CGRectMake(aV.frame.origin.x, aV.frame.origin.y - self.view.frame.size.height, aV.frame.size.width, aV.frame.size.height);

        // Animate drop
        [UIView animateWithDuration:0.5 delay:0.04*[views indexOfObject:aV] options: UIViewAnimationOptionCurveLinear animations:^{

            aV.frame = endFrame;

            // Animate squash
        }completion:^(BOOL finished){
            if (finished) {
                [UIView animateWithDuration:0.05 animations:^{
                    aV.transform = CGAffineTransformMakeScale(1.0, 0.8);

                }completion:^(BOOL finished){
                    if (finished) {
                        [UIView animateWithDuration:0.1 animations:^{
                            aV.transform = CGAffineTransformIdentity;
                        }];
                    }
                }];
            }
        }];
    }
}

I get to know that, the frame which is assigning is contains NaN value, I checked this with CGRectEmpty function and setting that frame to CGRectZero but it wont work.

I got this working code from here, https://stackoverflow.com/a/7045916/1603234

Backtrace / Debug Log

*** Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer position contains NaN: [594.947 nan]'
*** First throw call stack:
(
    0   CoreFoundation                      0x048551e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x034ad8e5 objc_exception_throw + 44
    2   CoreFoundation                      0x04854fbb +[NSException raise:format:] + 139
    3   QuartzCore                          0x01a1be1a _ZN2CA5Layer12set_positionERKNS_4Vec2IdEEb + 190
    4   QuartzCore                          0x01a1bfd9 -[CALayer setPosition:] + 68
    5   QuartzCore                          0x01a1c6df -[CALayer setFrame:] + 799
    6   UIKit                               0x01fbbb4d -[UIView(Geometry) setFrame:] + 302
    7   MyAppName                           0x0026b025 -[ResultMapViewController mapView:didAddAnnotationViews:] + 2133
    8   MapKit                              0x01e0449b -[MKMapView annotationManager:didAddAnnotationRepresentations:] + 272
    9   MapKit                              0x01e3b53c -[MKAnnotationManager updateVisibleAnnotations] + 2052
    10  Foundation                          0x02ed6de7 __NSFireTimer + 97
    11  CoreFoundation                      0x04813ac6 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 22
    12  CoreFoundation                      0x048134ad __CFRunLoopDoTimer + 1181
    13  CoreFoundation                      0x047fb538 __CFRunLoopRun + 1816
    14  CoreFoundation                      0x047fa9d3 CFRunLoopRunSpecific + 467
    15  CoreFoundation                      0x047fa7eb CFRunLoopRunInMode + 123
    16  GraphicsServices                    0x03ccd5ee GSEventRunModal + 192
    17  GraphicsServices                    0x03ccd42b GSEventRun + 104
    18  UIKit                               0x01f60f9b UIApplicationMain + 1225
    19  MyAppName                           0x0001ba3d main + 141
    20  MyAppName                           0x000027e5 start + 53
)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

OMG! I didn't know I could make such "silly" mistake.

Yes, the sentence in question The same code works fine on an iPhone. I was getting error CALayer position contains NaN because in my custom - (AnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id ) annotation method, where I am calculating

annotationView.layer.anchorPoint = CGPointMake(0.5, 1.0 - (diffFromBottom * 1.0)/annotationView.image.size.height);

annotationView.image was blank because I forgot to add the pin image in iPad project. It was there in iPhone code. So it was divided by Zero (0) and cause an error.

I put break point, and print with NSLog get to know that,

1.0 - (diffFromBottom * 1.0)/annotationView.image.size.height the value of this was printed, -inf. This was causing the app crash.

Basically, this error occurs if you'll perform a division by infinity or zero so whenever you got such error first look in code, where you performing the division operation.