UITextField, when resigning first responder, causing strange animation scroll of text

Question

I've got a couple of UITextFields implemented in a UITableView for a login form. When resigning first responder in both the very first time, a really strange animation jump is occurring. Since these are almost entirely build in Interface Builder with a .xib file, I've got virtually no code to add in. But here's a fun .gif that shows the behavior:

Update:

I've narrowed it down to the fact that I'm listening to keyboard events to adjust the view constraints. This is the code that's causing the problem:

func keyboardWillHide(notification: NSNotification) {
    // tried self.formContainer.layoutIfNeeded() here too to force pending layouts
    formContainerYConstraint.constant = 40
    UIView.animateWithDuration(0.4) { () -> Void in
        self.formContainer.layoutIfNeeded()
    }
}

... where the form container is a view that houses the table view and login button.

how you switching control from first text field to second one — Rohit Pradhan, Jan 31 '16 at 06:38
silly but just for confirmation?Is it a textView or TextField?? — Rohit Pradhan, Jan 31 '16 at 07:27
Are you reloading the cell or the table? Show what code you do have. — Wain, Jan 31 '16 at 07:44
Rohit - yes text**field**, Wain I'll add the table view delegate code in shortly. — brandonscript, Jan 31 '16 at 16:57
I have the same problem. Specifically this happens when resigning first responder in the same layout loop as you call `layoutIfNeeded` in an `animateWithDuration` block. — mattsson, Feb 03 '16 at 08:56
Can be related to issue with `sizeThatFits:` and UITextView on iOS 8. http://stackoverflow.com/questions/30519940 — Valentin Shergin, Mar 07 '17 at 00:14

score 4 · Answer 1 · answered Jan 31 '16 at 20:06

4

Feels like a total hack (and I'd love for someone to post a better answer) but in the mean time, I've resolved this by adding a slight delay to the animation action - I suspect this is related to the become- and resignFirstResponder events occurring when switching between two input fields.

let delay: dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, Int64(0.1 * Double(NSEC_PER_SEC)))
dispatch_after(delay, dispatch_get_main_queue()) { () -> Void in
    self.formContainerYConstraint.constant = 40
    UIView.animateWithDuration(0.4) { () -> Void in
        self.formContainer.layoutIfNeeded()
    }
}

answered Jan 31 '16 at 20:06

brandonscript

68,675
32
163
220

Was about to post the exact same question with the exact same hacky solution. I haven't been able to find anything better either. – mattsson Feb 03 '16 at 08:55
1

Interestingly for me before I applied the above code the animation duration was not respected and seemed to automatically sync with the keyboard animation. After adding dispatch_after I had to tweak the animation duration to try and match what the keyboard was doing – Doug Amos Jul 04 '16 at 10:26
Yeah it's an ugly hack for sure – brandonscript Jul 04 '16 at 15:03

score 1 · Answer 2 · answered May 05 '17 at 15:37

1

Try this

- (void)textFieldDidEndEditing:(UITextField *)textField
{
  [textField layoutIfNeeded];
}

answered May 05 '17 at 15:37

Jim75

737
8
13

as suggested here:http://stackoverflow.com/questions/33544054/why-is-uitextfield-animating-on-resignfirstresponder/35407734#35407734 – Jim75 May 05 '17 at 15:39

UITextField, when resigning first responder, causing strange animation scroll of text

2 Answers2