滚动视图和键盘问题Swift

Question

I have a view controller with scrollview inside and I set it in this way (with autolayout) in storyboard:

Example

As you can see I add all objects in the last view (called 'viewsotto') inside in the scrollview. My problem is that: Some of these objects are textfield and I want that when I tap on it and keyboard shows it can be down the textfield so that I can see what I write in it. For this reason I do it in this way:

NotificationCenter.default.addObserver(self, selector: #selector(userProfiloGiusto.keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(userProfiloGiusto.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)

func keyboardWillShow(notification: NSNotification) {

        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            if self.view.frame.origin.y == 0{
                self.view.frame.origin.y -= keyboardSize.height
            }
        }

    }

    func keyboardWillHide(notification: NSNotification) {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            if self.view.frame.origin.y != 0{
                self.view.frame.origin.y += keyboardSize.height
            }
        }
    }

but it doesn't work. What am I doing wrong?

Answer 1

Try below code. Firstly add var activeField: UITextField? to check is textfield availability. Then in view did load call this function:

override func viewDidLoad() {
    super.viewDidLoad()self.registerForKeyboardNotifications()

    let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(self.dismissKeyboard))
    view.addGestureRecognizer(tap)
    tap.cancelsTouchesInView = false}


func registerForKeyboardNotifications()
{
    //Adding notifies on keyboard appearing
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ProfileReviewViewController.keyboardWasShown(_:)), name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ProfileReviewViewController.keyboardWillBeHidden(_:)), name: UIKeyboardWillHideNotification, object: nil)
}


func deregisterFromKeyboardNotifications()
{
    //Removing notifies on keyboard appearing
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}
func keyboardWasShown(notification: NSNotification)
{
    //Need to calculate keyboard exact size due to Apple suggestions
    let info : NSDictionary = notification.userInfo!
    let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size
    let contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize!.height, 0.0)


    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets
    var aRect : CGRect = self.view.frame
    aRect.size.height -= keyboardSize!.height
    if activeField != nil
    {
        if (CGRectContainsPoint(aRect, activeField!.frame.origin))
        {
            scrollView.scrollRectToVisible(activeField!.frame, animated: true)
        }
    }
}

func keyboardWillBeHidden(notification: NSNotification)
{
    self.scrollView.contentInset = UIEdgeInsetsZero
}
//MARK : Textfield delegate methods
func textFieldDidBeginEditing(textField: UITextField) {
    activeField = textField
}

func textFieldShouldReturn(textField: UITextField) -> Bool {

    self.view.endEditing(true)
    activeField = nil
    return false
}
func textFieldShouldEndEditing(textField: UITextField) -> Bool {  //delegate method

    activeField = nil
    return true
}
func dismissKeyboard() {
    //Causes the view (or one of its embedded text fields) to resign the first responder status.

    activeField = nil
    view.endEditing(true)
}

Answer 2

Most probably the readings you are using to understand if there is overlapping are not correct.
It's a common issue, you are confronting them with your main view, instead you should get the frame of the textfield, make the right conversion to see if the keyboard is overlapping it and adjust the content inset of the scrollview accordingly.z
This is well explained in the Managing the keyboard documentation.
When the keyboard is shown:

func keyboardWasShown(notification: NSNotification)
{
    let info : NSDictionary = notification.userInfo!
    let keyboardSize = (info[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue().size!
    let contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize.height, 0.0)


    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets

    // If active text field is hidden by keyboard, scroll it so it's visible
    // Your app might not need or want this behavior.
    var aRect : CGRect = self.view.frame
    aRect.size.height -= keyboardSize.height
    if let actField = activeField
    {
        if (CGRectContainsPoint(aRect, actField.frame.origin))
        {
            scrollView.scrollRectToVisible(actField.frame, animated: true)
        }
    }
}

The important point is when they ask the view height, they subtract the keyboard height and they check of the text view is inside that area.
This calculation may change in relation with your view hierarchy, this is becaus ea frame is the the position of a view respect its superview, thus if your rect is inside another view, you need to convert its frame to obtain which is its frame related to the main view.