dismissModalView crash iphone app, but not with debugger on

Question

Hi all,

I have an iphone app with a modal view. The app crashes when the modal view get dismissed. As soon as the modal disappear at the bottom of the screen, and consequently the original view is shown behind, then the app crashes with no entry in console view.

I have tried to switch debugger on and I discovered that the app just run fine, with no crashes at all.

-First, I would like to know why such behaviour, shouldn't the debugger sit just on top without "disturbing" the app ? -Second, without debugger, can you point out what should I look at to solve my problem ? Or if you encounter something similiar ? Please be as much specific you can, because I am not an expert in objective-c programming.

I don't know what details to give you, the app is a normal one with standard iphone component, but for start I can say the modal view (which is built with IB) is called inside a NavigationBar system.

thanks

Answer 1

When these types of things happen, it is almost always because of memory allocation issues. The first step I would take is to do a "Clean All" and a "Build and Analyze", and look at all the analysis warnings. Analyze is very good at finding basic "use before allocate", "use after deallocate", or "wrong number of retains/releases" types of problems.

The next step is to turn on "Zombie" detection mode, which looks for accesses on memory that has already been deleted (in other words, killed objects coming back from the dead.) To do this, get info on your executable, go to the Arguments tab, and add a "variable to be set in the environment" of "NSZombieEnabled" to value "YES". Then look in the console when you run to see if something looks off.

Finally, you might try creating a new configuration where you use all the release mode settings for optimization, but add debug symbols. Maybe that will shake up the allocation disbursement in memory enough to trigger the bug in debug mode.