Question

I have some serious problems with my app right now. Okay, so there are two “sign up” buttons. The upper one is “sign up” and the one below is “sign in”. So if I fill out all the fields and press the “sign up” button (the upper one), then it will take me to the most right view in my storyboard image (look at the image provided) which will be called by:

ConfirmationScreenController *csc = [self.storyboard instantiateViewControllerWithIdentifier:@"Confirmation Screen"];
[self.view addSubview:csc.view];

and this works fine. The view shows up, but if i click the “login” button on the bottom the application crashes. The button calls this method:

-(IBAction)logIn:(id)sender {
    NSLog(@"hello");}

I hooked everything up correctly I think. The strange part is : When I reset the content and settings, and run it again it will log “hello” once or twice, but when I click it once again it crashes again with (gdb). Or one time it said I called the method on __NSCFTimer, even though I have never set up any timer or even sent anything to a timer … What the hell is this ?

All the buttons on the MainViewController work fine.

By the way, there are no warnings when building or at runtime.

This is the backtrace:

#0  0x0183709b in objc_msgSend ()
#1  0x00024570 in -[UIApplication sendAction:to:from:forEvent:] ()
#2  0x0002455a in -[UIApplication sendAction:toTarget:fromSender:forEvent:] ()
#3  0x000c9b76 in -[UIControl sendAction:to:forEvent:] ()
#4  0x000ca03f in -[UIControl(Internal) _sendActionsForEvents:withEvent:] ()
#5  0x000c92fe in -[UIControl touchesEnded:withEvent:] ()
#6  0x00049a30 in -[UIWindow _sendTouchesForEvent:] ()
#7  0x00049c56 in -[UIWindow sendEvent:] ()
#8  0x00030384 in -[UIApplication sendEvent:] ()
#9  0x00023aa9 in _UIApplicationHandleEvent ()
#10 0x0157dfa9 in PurpleEventCallback ()
#11 0x016671c5 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()
#12 0x015cc022 in __CFRunLoopDoSource1 ()
#13 0x015ca90a in __CFRunLoopRun ()
#14 0x015c9db4 in CFRunLoopRunSpecific ()
#15 0x015c9ccb in CFRunLoopRunInMode ()
#16 0x0157c879 in GSEventRunModal ()
#17 0x0157c93e in GSEventRun ()
#18 0x00021a9b in UIApplicationMain ()
#19 0x000026f8 in main (argc=1, argv=0xbffff65c) at /Users/Martin/Desktop/MyApplication/MyApplication/main.m:16
Current language:  auto; currently objective-c

Answer 1

I had this same issue, and it was because I didn’t have a strong reference to the controller being created and presented – which the IBAction was then being called on.

Essentially, the controller is created and displayed but no one has a reference to it after that so its reference count goes to zero and it goes out of memory. So calling an action will result in an EXC_BAD_ACCESS.