Animating constraint to push UIView above Keyboard issue

Question

I have this CommentViewController. It's embedded in a Container View. In this CommentViewController, there's a UITableView to display comments and UIView that contains a UITextField and a UIButton. The UIView that's containing those 2 objects is fixed via autolayout in the bottom, right and left to the Safe Area and top to the UITableView.

Now, when the user taps the UITextField, the whole view (with the button and the textfield inside) should be lifted above the keyboard. I'm trying to animated the bottom constraint of the view, but it's not working.

This is the code:

override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(_:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide(_:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)

}

@objc func keyboardWillShow(_ notification: NSNotification) {
    let keyboardFrame = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as AnyObject).cgRectValue
    UIView.animate(withDuration: 0.3) {
        self.textFieldViewBottomConstraint.constant = keyboardFrame!.height
    }
}

This is storyboard:

This is the result after you tap the text field.

PS: when I tap on UITextField, the console shows this message:

2018-06-04 14:11:52.471848+0300 AppName[91846:8829073] [MC] System group container for systemgroup.com.apple.configurationprofiles path is /Users/d/Library/Developer/CoreSimulator/Devices/C89347A2-1598-4F31-BBAC-1F98F970A248/data/Containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles 2018-06-04 14:11:52.472588+0300 Shippers[91846:8829073] [MC] Reading from private effective user settings.

If you need just the functionality. Check this out, https://github.com/hackiftekhar/IQKeyboardManager — ymutlu, Jun 04 '18 at 10:47
For [MC] messages, it's unrelated and you can ignore those: https://stackoverflow.com/questions/39588500/system-group-container-for-systemgroup-com-apple-configurationprofiles-path — Cœur, Jun 08 '18 at 03:09

Shehata Gamal · Accepted Answer · 2018-06-04T11:43:05.917

4

You need to call self.view.layoutIfNeeded() after changing the constraint's constant

self.textFieldViewBottomConstraint.constant = keyboardFrame!.height
   UIView.animate(withDuration: 0.3) {
    self.view.layoutIfNeeded()
}

//

 NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(_:)), name: NSNotification.Name.UIKeyboardDidShow, object: nil)

Edit:

Setting constant property for the bottom constraint depends on which element is the first in the constraint so if the constraint looks like this

Here textfield is the first

textfield_Bottom = view_Bottom * multiplier + constant. —> then constant must be minus as Y axis decrease when go to up which what we want to make the view goes up when keyboard is shown

Here view is the first

view_Bottom = textfield_Bottom * multiplier + constant. —> then constant must be plus

edited Jun 04 '18 at 11:43

answered Jun 04 '18 at 10:48

Shehata Gamal

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try UIKeyboardDidShow – Shehata Gamal Jun 04 '18 at 10:56
Can you be a little more specific, please? – Dani Jun 04 '18 at 10:57
Sadly, no. Again, no result. Could the issue be the fact that this `CommentViewController` is actually in the container view? Also, when I tap on the `UITextField` the console shows this message: (see my updated answer) – Dani Jun 04 '18 at 11:12
can you print anything inside the function to see whether it runs or not – Shehata Gamal Jun 04 '18 at 11:16
Yes, I also had suspicions that the function was not being called, but it is. I see the printed statement – Dani Jun 04 '18 at 11:18
check if you have to set -(minus)keyboardFrame!.height instead of keyboardFrame!.height – Shehata Gamal Jun 04 '18 at 11:25

Animating constraint to push UIView above Keyboard issue

1 Answers1