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A few days ago I created a app based on the scroll-view application I saw on the book Beginning iOS 4 Application Development .The scroll-view will displays smartly when I touch the textfield. but it always crash when I touch the another textfield.

the debugger display:

2012-07-31 21:32:35.721 View-based Application[1515:c07] -[ViewController keyboardDidShow:]: unrecognized selector sent to instance 0x6a3e400 2012-07-31 21:32:35.723 View-based Application[1515:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ViewController keyboardDidShow:]: unrecognized selector sent to instance 0x6a3e400' *** First throw call stack: (0x14b2022 0xeb2cd6 0x14b3cbd 0x1418ed0 0x1418cb2 0x9d7a29 0x147d855 0x147d778 0x91c19a 0x3ab845 0xbfe1bc4 0x3a6e01 0x4f757 0x45e49 0x45f34 0xbfe5aac 0x1d8ab54 0x3d93509 0x13e9803 0x13e8d84 0x13e8c9b 0x139b7d8 0x139b88a 0x15626 0x2182 0x20f5) terminate called throwing an exception(lldb)

I am new to iOS develop.I really don't know whats wrong. Here is the viewController.m code. Perhaps it is bit long. Please help me. If someone need the whole code,I can send it to him. My e-mail address:[email protected]

 #import "ViewController.h" @interface ViewController () @end @implementation ViewController @synthesize scrollView; -(void) viewWillAppear:(BOOL)animated{ //---registers the notifications for keyboard--- [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:self.view.window]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardDidHide) name:UIKeyboardDidHideNotification object:nil]; } //---when a TextField view begins editing--- -(void) textFieldDidBeginEditing:(UITextField *)textFieldView{ currentTextField = textFieldView; } //---when the user taps on the return key on the keyboard--- -(BOOL) textFieldShouldReturn:(UITextField *) textFieldView { [textFieldView resignFirstResponder]; return NO; } //---when a TextField view is done editing--- -(void) textFieldDidEndEditing:(UITextField *) textFieldView { currentTextField = nil; } //---when the keyboard appears--- -(void) keyboardDidshow:(NSNotification *) notification { if (keyboardIsShown) return; NSDictionary* info = [notification userInfo]; //---obtain the size of the keyboard--- NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey]; CGRect keyboardRect = [self.view convertRect:[aValue CGRectValue] fromView:nil]; NSLog(@"%f", [aValue CGRectValue].size.height); NSLog(@"%f",keyboardRect.size.height); //---resize the scroll view (with keyboard)--- CGRect viewFrame = [scrollView frame]; viewFrame.size.height -= keyboardRect.size.height; scrollView.frame = viewFrame; //---scroll to the current text field--- CGRect textFieldRect = [currentTextField frame]; [scrollView scrollRectToVisible:textFieldRect animated:YES]; keyboardIsShown = YES; } //---when the keyboard disappears--- -(void) keyboardDidHide:(NSNotification *) notification { NSDictionary* info = [notification userInfo]; //---obtain the size of the keyboard--- NSValue* aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey]; CGRect keyboardRect = [self.view convertRect:[aValue CGRectValue] fromView:nil]; //---resize the scroll view back to the orginal size (without keyboard)--- CGRect viewFrame = [scrollView frame]; viewFrame.size.height += keyboardRect.size.height; scrollView.frame = viewFrame; keyboardIsShown = NO; } //---before the View window disapppear-- -(void) viewWillDisappear:(BOOL)animated{ //---removes the notifications for keyboard--- [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidShowNotification object:nil]; [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil]; } - (void)viewDidLoad { scrollView.frame = CGRectMake(0,0,320,460); [scrollView setContentSize:CGSizeMake(320, 701)]; [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. } - (void)viewDidUnload { [super viewDidUnload]; // Release any retained subviews of the main view. } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown); } @end
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    Welcome to Stack Overflow. Please read the FAQ. If you get an error such as this, you might want to try to Google "unrecognized selector sent to instance" Commented Jul 31, 2012 at 14:26

2 Answers 2

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2

You appear to have a typo:

-(void) keyboardDidshow:(NSNotification *) notification {

should be

-(void) keyboardDidShow:(NSNotification *) notification { ^

Edit

Thank you @trojanfoe (and @jrturton 11 seconds late :P) for pointing out 

-(void) keyboardDidhide:(NSNotification *) notification {

should be

-(void) keyboardDidHide:(NSNotification *) notification { ^
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3 Comments

And when that is corrected, you'll have another one - keyBoardDidHide versus keyboardDidHide: (note the colon too)
Also the addObserver call: @selector(keyBoardDidHide) (mispelt and missing :).
@trojanfoe misspelled or misspelt =]
2

Your method name is different from the method that you have registered your notification to. This exception is being thrown because you class doesn't recognise the method that is being called by the Notification.

Notification: keyboardDid S how Method declaration: keyboardDid s how

Remember that Objective-C is case sensitive.

Change you method name to match the method you've passing as the selector parameter and you should be fine.

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