App Crashing at random!

[mgales]

I am writing my first test app, and am having a few problems with it.

The app consists of a TabBar, currently with only 1 Tab, and a TableView. The TableView pushes new views into place when items are selected.

On the detail view there is a button to push a map view. This uses the MapView control.

The app works as expected, but will crash (exit) at random times when switching back and forth between the TableViews.

The app only seems to crash when on an actual device, it seems to work fine in the Simulator.

I have ran the app through Instruments using the Leaks option, and have fixed the couple of leaks that were in my code (I wasn't releasing things properly), but I still have the intermittent crash problem.

I have been moving through the TableView quite quickly, and was wondering if it is just me being impatient.

If anyone has any additional ways to try and solve this problem, the help would be appriciated.

[smasher]

Originally Posted by mgales

If anyone has any additional ways to try and solve this problem, the help would be appriciated.

Is there any message in the console when the app crashes?

Search for NSZombies and the clang static analyzer. They're both tools that can help you find bugs in your code. It sounds like you may be releasing something *too* much now.

[mgales]

Originally Posted by smasher

Is there any message in the console when the app crashes?

Search for NSZombies and the clang static analyzer. They're both tools that can help you find bugs in your code. It sounds like you may be releasing something *too* much now.

Thanks for your reply. I have no message in the console as the app doesn't crash in the simulator.

I will look for the tools you have suggested and give those a try. Are these tools a part of the SDK or are they downloaded from somewhere else? If they are additional downloads, would you be able to supply a link to where they can be got from?

Thanks,

[smasher]

Originally Posted by mgales

Thanks for your reply. I have no message in the console as the app doesn't crash in the simulator.

I will look for the tools you have suggested and give those a try. Are these tools a part of the SDK or are they downloaded from somewhere else? If they are additional downloads, would you be able to supply a link to where they can be got from?

Thanks,

You should still be able to see messages in the console, if you're running your app in the device directly from XCode.

NSZombies:
CocoaDev: NSZombieEnabled

Clang:
Clang Static Analyzer

[mgales]

Originally Posted by smasher

You should still be able to see messages in the console, if you're running your app in the device directly from XCode.

NSZombies:
CocoaDev: NSZombieEnabled

Clang:
Clang Static Analyzer

Thanks for that.

I have enabled NSZombie, and this is the error I get: -

-[MapViewController respondsToSelector:]: message sent to deallocated instance 0x10bc300

This occurs when I click the Back button in my Navigation Bar!

The view it is moving from contains a MapView!

I have narrowed the problem to the following: -

- (void)mapView {
MapViewController *mvController = [[MapViewController alloc] initWithNibName:@"MapView" bundle:[NSBundle mainBundle]];

[mvController setItemLocation:[NSString stringWithFormat:@"%@ %@", [details objectForKey:@"Latitude"], [details objectForKey:@"Longitude"]]];

[self.navigationController pushViewController:mvController animated:YES];

//[mvController release];
}

If I uncomment the [mvController release]; line the app crashed.... Shouldn't mvController be released?

The app works without this line, and I cannot find any leaks!

Thanks

[shomarim]

Originally Posted by mgales

Thanks for that.

I have enabled NSZombie, and this is the error I get: -

-[MapViewController respondsToSelector:]: message sent to deallocated instance 0x10bc300

This occurs when I click the Back button in my Navigation Bar!

The view it is moving from contains a MapView!

I have narrowed the problem to the following: -

- (void)mapView {
MapViewController *mvController = [[MapViewController alloc] initWithNibName:@"MapView" bundle:[NSBundle mainBundle]];

[mvController setItemLocation:[NSString stringWithFormat:@"%@ %@", [details objectForKey:@"Latitude"], [details objectForKey:@"Longitude"]]];

[self.navigationController pushViewController:mvController animated:YES];

//[mvController release];
}

If I uncomment the [mvController release]; line the app crashed.... Shouldn't mvController be released?

The app works without this line, and I cannot find any leaks!

Thanks

Did you ever find a solution? I'm having the exact same problem.

[shomarim]

I found the solution:
Have You Found A Bug In MapKit? I Did. - JakeBehrens.com

Basically, set the MKMapView delegate to nil in dealloc.
mapView.delegate = nil;

I found that I also had to set
mapView.showsUserLocation = NO;
[mapView removeAnnotations:mapView.annotations];

If you're using location manager and its updating, set its delegate to nil in dealloc.

[Peeks]

I'm using CLLocationManager to get my current location.
Everything works fine with the fix described in this post.

But when I set mapView.showsUserLocation = YES; I get the same bad access exception. I have set it back to NO in dealloc but that doesn't help.

Is there a conflict between Location Manager and showsUserLocation? How can I use both without it crashing?

[hello24]

This looks like a over-released local variable in one of the views. Try using NSZombie and you'll get a meaningful message in the console.

[Peeks]

Originally Posted by hello24

This looks like a over-released local variable in one of the views. Try using NSZombie and you'll get a meaningful message in the console.

I got this Message

-[MKMapView userLocationViewAccuracyDidUpdate:]: message sent to deallocated instance 0x36f5fd0

The crash seems to occur when both the mapview.userlocation and my LocationManager update their view Accuracy.

[smasher]

Do you set a delegate for MKMapview? You should set the delegate property back to nil when you're done with it, otherwise it will keep calling methods on the delegate object even after the delegate object is destroyed.

[vibhorgoyal]

Originally Posted by shomarim

I found the solution:
Have You Found A Bug In MapKit? I Did. - JakeBehrens.com

Basically, set the MKMapView delegate to nil in dealloc.
mapView.delegate = nil;

I found that I also had to set
mapView.showsUserLocation = NO;
[mapView removeAnnotations:mapView.annotations];

If you're using location manager and its updating, set its delegate to nil in dealloc.

Thanks a lot. You saved my day!

[ratbastid]

Originally Posted by smasher

Do you set a delegate for MKMapview? You should set the delegate property back to nil when you're done with it, otherwise it will keep calling methods on the delegate object even after the delegate object is destroyed.

That's exactly what's happening. Yesterday I had a VERY strange problem where a few seconds after backing out of a nav controller view, I'd crash with a call to a deallocated object.

After a lot of fussing around about NavController mishandling my view controllers, I realized that the deallocated object WAS the viewController I'd just popped. It was set as the delegate for a CLLocationManager object that was trying its darndest to report a new location.

Just telling it to stopUpdatingLocation in the controller's -(void)dealloc{ } was enough to stop the problem.

[hawshy]

Originally Posted by shomarim

I found the solution:
Have You Found A Bug In MapKit? I Did. - JakeBehrens.com

Basically, set the MKMapView delegate to nil in dealloc.
mapView.delegate = nil;

I found that I also had to set
mapView.showsUserLocation = NO;
[mapView removeAnnotations:mapView.annotations];

If you're using location manager and its updating, set its delegate to nil in dealloc.

This really help alot!! Thanks!

[iFabG]

Originally Posted by hawshy

This really help alot!! Thanks!

Just to give you my little experience: I had the same problem inside the the same navigation logic and had an autorelease in addNotation that gave me random errors.

Once deleted (and put in the dealloc) I fixed it.


Fabrizio

[gherman999]

Originally Posted by shomarim

I found the solution:
Have You Found A Bug In MapKit? I Did. - JakeBehrens.com

Basically, set the MKMapView delegate to nil in dealloc.
mapView.delegate = nil;

I found that I also had to set
mapView.showsUserLocation = NO;
[mapView removeAnnotations:mapView.annotations];

If you're using location manager and its updating, set its delegate to nil in dealloc.

shomarim: Thanks for the link and suggestion. I was having the exact problem and setting the delegate to nil worked perfectly. I also followed your other suggestions, just in case. The problem was only occurring when the user (device or simulator) pressed the back button too fast, before the view fully loaded. Otherwise, I never experienced the issue. Thanks again!

[IphoneSdk]

I never realised that iPhone SDK was related to Nike shoes, you learn something new everyday!