Question

I’m getting a crash from this routine after adding the :(id)sender so I could determine which button called it. When set up as plain old toggleView3 it works perfectly. The crash occurs when detailView is toggled back to docView.

'NSInvalidArgumentException', reason: '*** -[RootViewController toggleView3]: unrecognized selector sent to instance 0x524a00' 2009-04-07 12:29:44.421 eTarot[11405:20b] Stack:

-(IBAction)toggleView3:(id)sender{       if (detailViewController == nil) {         [self loadDetailViewController];     }      UIView *docView = docViewController.view;     UIView *detailView = detailViewController.view;      [UIView beginAnimations:nil context:NULL];     [UIView setAnimationDuration:1];     [UIView setAnimationTransition:([docView superview] ? UIViewAnimationTransitionFlipFromRight : UIViewAnimationTransitionFlipFromLeft) forView:self.view cache:YES];      if ([docView superview] != nil) {         [detailViewController viewWillAppear:YES];         [docViewController viewWillDisappear:YES];         [docView removeFromSuperview];          [self.view addSubview:detailView];         [self.view insertSubview:detailNavigationBar aboveSubview:detailView];         [docViewController viewDidDisappear:YES];         [detailViewController viewDidAppear:YES];      } else {         [docViewController viewWillAppear:YES];         [detailViewController viewWillDisappear:YES];         [detailView removeFromSuperview];         [detailNavigationBar removeFromSuperview];         [self.view addSubview:docView];         [detailViewController viewDidDisappear:YES];         [docViewController viewDidAppear:YES];     }     [UIView commitAnimations]; } 

Answer 1

You’re sending a view the message toggleView3 when the correct name of the selector is toggleView3: — that is, with a colon and argument. They may look similar to you, but they’re totally different methods to Objective-C.