Showing and hiding the keyboard on iOS

gistfile1.m

- (void)registerForKeyboardNotifications 
{
    
    [[NSNotificationCenter defaultCenter] addObserver:self
				selector:@selector(keyboardWillShow:)
				name:UIKeyboardWillShowNotification object:nil];
	
    [[NSNotificationCenter defaultCenter] addObserver:self
				selector:@selector(keyboardWillHide:)
				name:UIKeyboardWillHideNotification object:nil];
}

- (void)unregisterForKeyboardNotifications 
{
	[[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void)keyboardWillShow:(NSNotification *)notification {
    NSTimeInterval animationDuration;
    UIViewAnimationOptions curve;
    [[[notification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[[notification userInfo] objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&curve];
    
    // raw keyboard size, doesn't account for orientation
    NSValue *aValue = [[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey];
    CGSize keyboardSize = [aValue CGRectValue].size;

    // compute keyboard size for orientation
    UIViewController *rootViewController = [AppDelegate delegate].viewController;
    BOOL isPortrait = UIInterfaceOrientationIsPortrait(rootViewController.interfaceOrientation);
    CGFloat keyboardHeight = isPortrait ? keyboardSize.height : keyboardSize.width;
    CGFloat keyboardWidth = isPortrait ? keyboardSize.width : keyboardSize.height;
    CGSize orientedKeyboardSize = CGSizeMake(keyboardWidth, keyboardHeight);
    
    // run animation using keyboard's curve and duration 
    [UIView animateWithDuration:animationDuration delay:0.0 options:curve animations:^{
        
        // size or move views appropriately so they are not obscured by the keyboard
        
    } completion:^(BOOL completion) {
        
    }];
}

- (void)keyboardWillHide:(NSNotification *)notification 
{
    NSTimeInterval animationDuration;
	UIViewAnimationOptions curve;
    [[[notification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[[notification userInfo] objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&curve];
    
    // hiding is a bit easier
    // simply restore views back to original position
    
}