Question

I have many threads calling the following function by performSeleactoreOnMainThread method:

-(void) showAlert: (NSString *)message{
if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop]) {
    NSLog(@"<< perform in main thread>>");
    [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
}
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}

As, in any case, this method will be called only on main thread, I am not getting the reason for EXC_BAD_ACCESS crash on the line:
[alert show]

And this crash comes only sometimes. Please help.

Answer 1

I guess you forgot to add return; in your code so that your code below the if are also executed no matter it is in main loop or not.

a simple fix may be:

-(void) showAlert: (NSString *)message{
    if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop]) {
        NSLog(@"<< perform in main thread>>");
        [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
        return;
    }
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alert show];
}