The (not so) ultimate UIScrollView keyboard appearance and disappearance implementation

keyboard.m

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//  http://www.apache.org/licenses/LICENSE-2.0
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- (void)keyboardWillShowNotification:(NSNotification *)notification
{
    UIView *view = self.view;
    
    CGRect keyboardFrame = [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    keyboardFrame = [view convertRect:keyboardFrame fromView:self.view.window];
    
    // according to Apple docs you can't rely on the origin of the keyboard frame as it will be animating
    // so we can just work it out manually
    keyboardFrame.origin.x = 0;
    keyboardFrame.origin.y = CGRectGetHeight([UIScreen mainScreen].bounds) - CGRectGetHeight(keyboardFrame);
    
    // don't adjust the offsets if the keyboard is now obscuring the view
    if (!CGRectIntersectsRect(keyboardFrame, view.frame)) {
        return;
    }
    
    CGFloat duration = [[[notification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    NSInteger animationCurve = [[[notification userInfo] objectForKey:UIKeyboardAnimationCurveUserInfoKey] integerValue];
    CGRect intersection = CGRectIntersection(keyboardFrame, view.frame);
    
    UIEdgeInsets insets = self.scrollView.contentInset;
    insets.bottom = intersection.size.height;
    
    [UIView animateWithDuration:duration delay:0.0f options:animationCurve animations:^{
        self.scrollView.contentInset = insets;
        self.scrollView.scrollIndicatorInsets = insets;
    } completion:nil];
}


- (void)keyboardWillHideNotification:(NSNotification *)notification
{
    CGFloat duration = [[[notification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    NSInteger animationCurve = [[[notification userInfo] objectForKey:UIKeyboardAnimationCurveUserInfoKey] integerValue];
    
    UIEdgeInsets insets = self.scrollView.contentInset;
    insets.bottom = 0;
    
    [UIView animateWithDuration:duration delay:0.0f options:animationCurve animations:^{
        self.scrollView.contentInset = insets;
        self.scrollView.scrollIndicatorInsets = self.scrollView.contentInset;
    } completion:nil];
}

This code will adjust the scrollview offsets to account for keyboard overlap. It calculates the intersection and adjusts accordingly. This means this will work if the UIViewController is presented fullscreen or in a Popover on iPad and will only adjust the scroll insets if necessary.

Just add the two methods to your view controller, make sure you have a property for your UIScrollView called scrollView and add the following code to the top of your view controller:

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

- (void)viewDidLoad
{
    [super viewDidLoad];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShowNotification:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHideNotification:) name:UIKeyboardWillHideNotification object:nil];
}

Works on iOS 8 and later

Don't use this, it doesn't work, use http://stackoverflow.com/a/19660499/248848 instead