以编程方式滚动 ScrollView，其中包含 StackView

Question

I have a ScrollView with a StackView inside of it. When the keyboard appears I am changing the bottomConstraint .

1. view withouth keyboard
2. how it looks if keyboard shows
3. How it should look like

The problem is that I would like to scroll the ScrollView a bit up but I can not make it work.

scrollView.setContentOffset(CGPoint(x: x, y: y), animated: true) is NOT working. Ive tried it as you can see in the code but it has no effect:

Keyboard Observer methods

var keyboardHeight: CGFloat?
//MARK: keyboardObserver
@objc func keyboardWillShow(_ notification: Notification) {
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        let keyboardRectangle = keyboardFrame.cgRectValue
        self.keyboardHeight = keyboardRectangle.height

        if self.passwordWiederholenTextField.isEditing {
            scrollBottomViewConstraint.constant = -(self.keyboardHeight!)
            self.theScrollView.setContentOffset(CGPoint(x: 0, y: 20), animated: true)
            self.view.layoutIfNeeded()
        }

    }
}

@objc func keyboardWillHide(_ notification: Notification) {
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        let keyboardRectangle = keyboardFrame.cgRectValue
        self.keyboardHeight = keyboardRectangle.height

        if self.passwordWiederholenTextField.isEditing {
            scrollBottomViewConstraint.constant = 0
            self.view.layoutIfNeeded()
        }

    }
}

Constraints:

theScrollView.topAnchor.constraint(equalTo: theLabel.bottomAnchor, constant: 20).isActive = true
theScrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
theScrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
scrollBottomViewConstraint = theScrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
scrollBottomViewConstraint.isActive = true

theStackView.topAnchor.constraint(equalTo: theScrollView.topAnchor).isActive = true
theStackView.leadingAnchor.constraint(equalTo: theScrollView.leadingAnchor).isActive = true
theStackView.trailingAnchor.constraint(equalTo: theScrollView.trailingAnchor).isActive = true
theStackView.widthAnchor.constraint(equalTo: theScrollView.widthAnchor).isActive = true
stackViewBottomConstraint = theStackView.bottomAnchor.constraint(equalTo: theScrollView.bottomAnchor)
stackViewBottomConstraint.isActive = true

I couldn't find anything on this so if anyone has any idea why it is not working I am very grateful!

Answer 1

With @Arun's tip I managed to get it done. This is my final code and it works perfectly:

var keyboardHeight: CGFloat?
//MARK: keyboardObserver
@objc func keyboardWillShow(_ notification: Notification) {
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        let keyboardRectangle = keyboardFrame.cgRectValue
        self.keyboardHeight = keyboardRectangle.height

        let activeField: UITextField? = [passwordTextField, passwordWiederholenTextField].first { $0.isFirstResponder }

        switch activeField {
        case passwordTextField:
            let insets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardHeight! + 130, right: 0)
            theScrollView.contentInset = insets
            theScrollView.scrollIndicatorInsets = insets
            self.view.layoutIfNeeded()

        case passwordWiederholenTextField:
            let insets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardHeight! + 30, right: 0)
            theScrollView.contentInset = insets
            theScrollView.scrollIndicatorInsets = insets
            self.view.layoutIfNeeded()

        default:
            break
        }

    }
}

@objc func keyboardWillHide(_ notification: Notification) {
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        let keyboardRectangle = keyboardFrame.cgRectValue
        self.keyboardHeight = keyboardRectangle.height

        theScrollView.contentInset = UIEdgeInsets.zero
        theScrollView.scrollIndicatorInsets = UIEdgeInsets.zero

    }
}