How to use the default iOS7 UIAnimation curve

Question

iOS7 animations don't behave the same way as in iOS6. They appear to use a different bezier curve. Where iOS6 uses a kind of "easeInOutSine" curve, iOS7 is more of the "easeInOutExpo" kind. (http://matthewlein.com/ceaser/)

Is there a way to use that curve? I want to sync my animations when the keyboard opens/closes.

Phocomelia

Answer 1

Here's how I do it (at least when the keyboard is about to be shown)

- (void)keyboardWillShow:(NSNotification *)notification {
    NSDictionary *keyboardAnimationDetail = [notification userInfo];
    UIViewAnimationCurve animationCurve = [keyboardAnimationDetail[UIKeyboardAnimationCurveUserInfoKey] integerValue];
    CGFloat duration = [keyboardAnimationDetail[UIKeyboardAnimationDurationUserInfoKey] floatValue];

    [UIView animateWithDuration:duration delay:0.0 options:(animationCurve << 16) animations:^{
        // Set the new properties to be animated here
    } completion:nil];
}

You get the animation curve from the keyboard notification as usual and translate it to an animation option by bit-shifting it.

Jedthus

This is really clever. How would one get that animation before the keyboard is ever shown? – Ender

Just use (7 << 16) as an option for animateWithDuration. – Elviraelvis

Is there an official constant for that option? – Phocomelia

They are in the headers. I think it's a bit fragile myself as it depends on the implementation. There really should be a framework method to convert an animationCurve to an animationOption. I should raise a radar for it sometime. – Jedthus

Any thoughts on how to use this animation curve for a CAAnimation? – Ender

This is perfect for when the keyboard shows up, but why is it out of sync when the keyboard is dismissed? – Normative

Yeah this seems to be off for the keyboard dismissal. – Caterwaul

Interesting. The dismissing animation seems to be (6 << 16) even though it's reported to be (7 << 16) – Caterwaul

However, the duration parameter is invalid when using this animation option. Can anyone solve this? – Six

Answer 2

Update, fixed in 7.1. No longer necessary.

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For whatever reason, the animation curve reported on keyboard dismissal is incorrect. It seems to actually be 6 << 16 instead of 7 << 17.

Here's what I do with UIKeyboardWillChangeFrameNotification to determine which animation curve to use.

NSDictionary *keyboardAnimationDetail = [notification userInfo];

CGRect keyboardEndFrameWindow = [keyboardAnimationDetail[UIKeyboardFrameEndUserInfoKey] CGRectValue];

double keyboardTransitionDuration  = [keyboardAnimationDetail[UIKeyboardAnimationDurationUserInfoKey] doubleValue];

// gives incorrect value of 7 on dismissal
// UIViewAnimationCurve keyboardTransitionAnimationCurve  = [keyboardAnimationDetail[UIKeyboardAnimationCurveUserInfoKey] integerValue];

CGRect keyboardEndFrameView = [self.view convertRect:keyboardEndFrameWindow fromView:nil];

CGFloat newConstant = (self.view.frame.size.height - keyboardEndFrameView.origin.y);

[UIView animateWithDuration:keyboardTransitionDuration
                      delay:0.0f
                    options:newConstant == 0 ? (6 << 16) : (7 << 16)
                 animations:^{
                     self.tableView.contentInset = UIEdgeInsetsMake(self.tableView.contentInset.top, 0, self.view.frame.size.height - keyboardEndFrameView.origin.y + self.commentToolbar.frame.size.height, 0);
                     self.tableView.scrollIndicatorInsets = UIEdgeInsetsMake(self.tableView.scrollIndicatorInsets.top, 0, self.view.frame.size.height - keyboardEndFrameView.origin.y + self.commentToolbar.frame.size.height, 0);
                     self.commentViewToSuperviewBottomConstraint.constant = (self.view.frame.size.height - keyboardEndFrameView.origin.y);
                     [self.view layoutIfNeeded];
                 }
                 completion:^(__unused BOOL finished){
                 }];

Basically I determine if the keyboard frame is hiding by seeing if the new y origin will be just outside our view's frame (newConstant). Then based on that I use either 6 or 7:

newConstant == 0 ? (6 << 16) : (7 << 16)

The rest is just adjusting my tableView contentInset and scrollIndicatorInsets, as well as changing the constant on the toolbar that is moving with the keyboard.

Caterwaul

@Abizem's syntax certainly looks much nicer. – Caterwaul

Seems to be fixed in 7.0.3 – Outman

I don't think it was fixed in 7.0.3, but it IS fixed in 7.1. – Caterwaul