解雇UIActionSheet会产生EXC_BAD_ACCESS

Question

I've got an application with UITableView nested in a UITabBarController, and I have a method that's giving me an EXC_BAD_ACCESS when it's called from UIActionSheetDelegate method clickedButtonAtIndex:

The method that (sometimes) gives a problem is called updateTaskArray. Basically, it does a Core Data fetch that configures an NSMutableArray "taskArray" that's a property of the viewController (which the tableView delegate uses to configure its cells) then its last line is

[self.tableView reloadData];

The thing is, it works fine most of the time, but it only gives an error when it's called from the UIActionSheetDelegate. When I run it with NSZombieEnabled, it tells me

*** -[UITabBarButton setAlpha:]: message sent to deallocated instance 0x5c2e760

And with breakpoints, it doesn't give EXC_BAD_ACCESS until after the UIActionView delegate method (and updateTaskArray within it) complete. The UIActionSheet is presented with:

[actionSheet showFromTabBar:self.tabBarController.tabBar];

so I'm wondering if this means that it's dismissing the actionSheet that is causing the problem... but it doesn't give any error if I don't call updateTaskArray from the delegate...

I'm not really sure what would be a good next step as [UITabBarButton setAlpha:] isn't a method I'm calling "myself" and the error seems to occur after the code I've actually "written" has already run- any suggestions on where to start approaching this one?

Answer 1

I changed

[actionSheet showFromTabBar:self.tabBarController.tabBar];

to

[actionSheet showFromToolbar:self.navigationController.toolbar];

And it now works fine. The tabBarController is the parent of the navigation controller, I reckon it didn't like me going one level above.

Answer 2

Look at your release statements. You are releasing a UITabBarButton, or possibly the entire tab bar, when you shouldn't. Review principles of memory management for iOS.