EXC_BAD_ACCESS code 2 on UIAlertView in iOS6

问题

I'm trying to figure out why im getting this crash in my app.

It works perfectly fine in Xcode 4.4 running in the simulator with ios5.1, but when i switch into xcode 4.5 and ios6 I'm getting an EXC_BAD_ACCESS code 2. Here is my code:

- (void) myMethod
{
    UIAlertView *alertview = [[[UIAlertView alloc]initWithTitle:@"Title" message:@"message" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil] autorelease];
    alertview.tag = 1
    [alertview show];
}

this is giving me an EXC_BAD_ACCESS code 2 on the [UIAlertView show] line

any ideas?

thanks!

回答1:

I've got it. I have the same problem, in my case it seems that the method is thrown from background now (now in ios7, in ios6 UIAlertView was automatically put into the main-thread as @nodepond says -thanks!-)..

try to assure that the method is shown from main thread:

[alertView performSelectorOnMainThread:@selector(show) withObject:nil waitUntilDone:YES];

Good luck!

回答2:

It's happened with me, even in 2014. The problem is want to use an object already released.

What I did wrong:

//class B with UIAletViewDelegate

-(void) showAlert{
 UIAlertView * alert = [[UIAlertView alloc] initWithTitle bla bla...];
 [alert show];
}


//class A
viewDidLoad{
 MyClassB *B = [[B alloc] init];
 [B showAlert];
}

What is the right way:

//Class A
@implementation A{
    ClassB *B;
}

 viewDidLoad{
     B = [[B alloc] init];
     [B showAlert];
 }

来源：https://stackoverflow.com/questions/12468677/exc-bad-access-code-2-on-uialertview-in-ios6