iOS 7 back swipe gesture and keyboard dismissal

Question

I have a standard UINavigationViewController with a standard UIInteractivePopGestureRecognizer for iOS 7. I also have these well known and widely-used methods:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

They work like this:

- (void)keyboardWillShow:(NSNotification *)notification{
    CGFloat keyboardSlideDuration = [[[notification userInfo] objectForKey: UIKeyboardAnimationDurationUserInfoKey] floatValue];

    UIViewAnimationOptions keyboardAnimationCurve = [[notification userInfo][UIKeyboardAnimationCurveUserInfoKey] integerValue]<<16;

    if (keyboardIsUp || isAnimating) return;

    isAnimating = YES;

    [UIView animateWithDuration:keyboardSlideDuration delay:0 options:(keyboardAnimationCurve | UIViewAnimationOptionBeginFromCurrentState) animations:^{
        _topConstraint.constant -= kTopConstraintR4Ratio;
        [self.view layoutIfNeeded];
    }completion:^(BOOL finished){
        keyboardIsUp = YES;
        isAnimating = NO;
    }];
}

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

    CGFloat keyboardSlideDuration = [[[notification userInfo] objectForKey: UIKeyboardAnimationDurationUserInfoKey] floatValue];

    UIViewAnimationOptions keyboardAnimationCurve = [[notification userInfo][UIKeyboardAnimationCurveUserInfoKey] integerValue]<<16;

    if (isAnimating) return;

    isAnimating = YES;

    [UIView animateWithDuration:keyboardSlideDuration delay:0 options:(keyboardAnimationCurve | UIViewAnimationOptionBeginFromCurrentState) animations:^{
        _topConstraint.constant = topConstraintOriginalValue;
        [self.view layoutIfNeeded];
    } completion:^(BOOL finished) {
        keyboardIsUp = NO;
        isAnimating = NO;
    }];
}

The thing is that UIView animateWithDuration is triggered without any respect to duration when I swipe the view back with a gesture. The whole view turns into a mess - it animates slowly when I pop the view, but when the gesture isn't finished - the view jumps up.

It looks like this:

enter image description here

How do I get rid of this strange behavior? I don't want the view to move during the transition and I want it to stay still.

EDIT:

You can download the sample project using the link here:

https://www.dropbox.com/s/034lfy49ru4pelf/SampleProject.zip

@TonyD It might be, but it certainly **not** what I want and it looks more like a bug. — Sergey Grischyov, Jul 22 '14 at 14:35
I'm wondering, if you slide all the way to the right, will the keyboard be dismissed? — Anton, Jul 22 '14 at 16:33
@LeoNatan - check it out - https://www.dropbox.com/s/034lfy49ru4pelf/SampleProject.zip — Sergey Grischyov, Jul 24 '14 at 17:47
Have you tried unsubscribing from keyboard notifications in `-viewWillDisappear:` and subscribing back in `-viewDidAppear:`? — Nikolay Kasyanov, Jul 29 '14 at 10:56
@NikolayKasyanov tried it and it just doesn't work very well. — Sergey Grischyov, Jul 29 '14 at 11:02

avdyushin · Accepted Answer · 2014-07-28T13:10:36.517

3

Easy hack:

BOOL needAdjustContstrain;

Set needAdjustContstrain to YES in keyboardWillShow:

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    if (needAdjustContstrain) {
         _topContstraint.constant -=40;
    }
}

edited Jul 28 '14 at 13:10

answered Jul 28 '14 at 12:55

avdyushin

1,906
17
21

Well, that looks like it, as simple as it gets. Working on a sample project. I'll do some testing and report back with the results. Need to implement it on 4-5 VCs and see. – Sergey Grischyov Jul 28 '14 at 13:00
It seems to be buggy.. Check keyboard notification sequence when interactivePopGestureRecognizer in action – avdyushin Jul 28 '14 at 13:02
It will always call `keyboardWillHide` first and probably `keyboardWillShow` next – Sergey Grischyov Jul 28 '14 at 13:03
Yes, I think therefor my hack works only for first gesture, need to be tuned – avdyushin Jul 28 '14 at 13:05
Confirmed, the 2nd and subsequent gestures break all the harmony. – Sergey Grischyov Jul 28 '14 at 13:07
So when do we put the `BOOL` to `NO`, then? E.G. I need to hide the keyboard on the view and I don't want it to animate when I pop it. – Sergey Grischyov Jul 28 '14 at 13:12
There is, if I need to hide the keyboard and when I do, it will still be YES, therefore, the view will animate as if there's a keyboard. – Sergey Grischyov Jul 28 '14 at 13:14
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/58167/discussion-between-nucleus-and-sergiusgee). – avdyushin Jul 28 '14 at 13:17

score -2 · Answer 2 · edited May 23 '17 at 10:33

-2

you need to call the layoutIfneeded method before the animation block . Check out the code below :

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

CGFloat keyboardSlideDuration = [[[notification userInfo] objectForKey: UIKeyboardAnimationDurationUserInfoKey] floatValue];

UIViewAnimationOptions keyboardAnimationCurve = [[notification userInfo][UIKeyboardAnimationCurveUserInfoKey] integerValue]<<16;

if (isAnimating) return;

isAnimating = YES;

[self.view layoutIfNeeded];
[UIView animateWithDuration:keyboardSlideDuration delay:0 options:(keyboardAnimationCurve | UIViewAnimationOptionBeginFromCurrentState) animations:^{
    _topContstraint.constant = 89;
  //
} completion:^(BOOL finished) {
    keyboardIsUp = NO;
    isAnimating = NO;
}];}

Please check the link

edited May 23 '17 at 10:33

Community

1
1

answered Jul 28 '14 at 11:17

Singh

2,151
3
15
30

1

Not performing layout will not perform the animation correctly in other places of the code, where animation is needed. – Léo Natan Jul 28 '14 at 11:30
1

Absolutely not a credible answer - this way the animation is not being performed correctly, just like @LeoNatan said. – Sergey Grischyov Jul 28 '14 at 11:35
That's not going to work and has nothing to do to the UIInteractivePopGesture – Sergey Grischyov Jul 28 '14 at 12:01
@SergiusGee i have tested the above code and its working fine. – Singh Jul 28 '14 at 12:04
@sigkill What's working fine? The animation is broken, the view still moves with the gesture recognizer. How on earth do you expect to break the `UIView` animation cycle and expect it to work? – Sergey Grischyov Jul 28 '14 at 12:14
@sigkill Jesus, even the link you pointed out to says: `You need to call layoutIfNeeded within the animation block.` Do you even look what you post? Within != before. – Sergey Grischyov Jul 28 '14 at 12:15

iOS 7 back swipe gesture and keyboard dismissal

2 Answers2