App shuts down when pushing UIbutton!

Question

For reasons unknown my app shuts down upon pressing a UIButton in the simulator. I have dynamically added my UIView, if that is of relevance. No tracelog or debug information just a rush exit...

This is the simple code (.m-file):

- (IBAction) testButtonPressed: (id) sender{
    NSLog (@"Testbutton pressed.");
}

From the header file:

- (IBAction) testButtonPressed: (id) sender;

Pretty basic stuff, but for some reason the app terminates. Help!

EDIT The program crashes immediately when I either tap in a textfield, push a button or in any other way interact with the user interface. From my subview:

LoginViewController *myLoginViewController = [[LoginViewController alloc] initWithNibName:@"LoginView" bundle:nil];
[[UIApplication sharedApplication].keyWindow addSubview:myLoginViewController.view];
[[UIApplication sharedApplication].keyWindow makeKeyAndVisible];

Answer 1

additional information moved to question.