ScrollView and keyboard in Swift

I started creating a simple iOS app that does some operations.

But I'm having some problems when the keyboard appears, hiding one of my textfields.

I think it's a common problem and I did some research but I couldn't find anything that solved my problem.

I want to use a ScrollView rather than animate the textfield to make it visible.

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小开

You can animate your scrollview to center on your UITextField on keyboard appearance (ie. making your textfield the first responder) via a scroll offset. Here are a couple of good resources to get you started (there are a bunch on this site):

How programmatically move a UIScrollView to focus in a control above keyboard?

How to make a UIScrollView auto scroll when a UITextField becomes a first responder

Additionally, if you simply use a UITableView with your content in cells, when the textfield becomes first responder, the UITableViewController will automatically scroll to the textfield cell for you (though I'm not sure this is what you want to do).

小开

Reading the links you sent to me, I found a way to make it work, thanks!:

func textFieldDidBeginEditing(textField: UITextField) {
if (textField == //your_field) {
scrollView.setContentOffset(CGPointMake(0, field_extra.center.y-280), animated: true)
callAnimation()
viewDidLayoutSubviews()
}
}


func textFieldDidEndEditing(textField: UITextField) {
if (textField == //your_field){
scrollView .setContentOffset(CGPointMake(0, 0), animated: true)
viewDidLayoutSubviews()
}
}
小开

In ViewDidLoad, register the notifications:

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name:UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name:UIResponder.keyboardWillHideNotification, object: nil)

Add below observer methods which does the automatic scrolling when keyboard appears.

@objc func keyboardWillShow(notification:NSNotification) {


guard let userInfo = notification.userInfo else { return }
var keyboardFrame:CGRect = (userInfo[UIResponder.keyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
keyboardFrame = self.view.convert(keyboardFrame, from: nil)


var contentInset:UIEdgeInsets = self.scrollView.contentInset
contentInset.bottom = keyboardFrame.size.height + 20
scrollView.contentInset = contentInset
}


@objc func keyboardWillHide(notification:NSNotification) {


let contentInset:UIEdgeInsets = UIEdgeInsets.zero
scrollView.contentInset = contentInset
}
小开

The top answer for swift 3:

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

And then: 

func keyboardWillShow(notification:NSNotification){
//give room at the bottom of the scroll view, so it doesn't cover up anything the user needs to tap
var userInfo = notification.userInfo!
var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
keyboardFrame = self.view.convert(keyboardFrame, from: nil)


var contentInset:UIEdgeInsets = self.theScrollView.contentInset
contentInset.bottom = keyboardFrame.size.height
theScrollView.contentInset = contentInset
}


func keyboardWillHide(notification:NSNotification){
let contentInset:UIEdgeInsets = UIEdgeInsets.zero
theScrollView.contentInset = contentInset
}
小开

An answer for Swift 3, based on the one proposed by Daniel Jones, but safer (thanks to the guard), more concise and with consistent scroll indicator insets:

@objc private func keyboardWillBeShown(notification: NSNotification) {
guard let keyboardFrameValue = notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue else { return }
let keyboardFrame = view.convert(keyboardFrameValue.cgRectValue, from: nil)
scrollView.contentInset.bottom = keyboardFrame.size.height
scrollView.scrollIndicatorInsets = scrollView.contentInset
}


@objc private func keyboardWillBeHidden() {
scrollView.contentInset = .zero
scrollView.scrollIndicatorInsets = scrollView.contentInset
}
小开 
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.


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


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


}


func keyboardWillShow(_ notification:Notification) {


if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardSize.height, 0)
}
}
func keyboardWillHide(_ notification:Notification) {


if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
tableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
}
}
小开

contentInset doesn't work for me, because I want the scrollview move all the way up above the keyboard. So I use contentOffset:

func keyboardWillShow(notification:NSNotification) {
guard let keyboardFrameValue = notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue else {
return
}
let keyboardFrame = view.convert(keyboardFrameValue.cgRectValue, from: nil)
scrollView.contentOffset = CGPoint(x:0, y:keyboardFrame.size.height)
}


func keyboardWillHide(notification:NSNotification) {
scrollView.contentOffset = .zero
}
小开

Here is a complete solution, utilizing guard and concise code. Plus correct code in keyboardWillHide to only reset the bottom to 0.

@IBOutlet private weak var scrollView: UIScrollView!


override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
registerNotifications()
}


override func viewDidDisappear(_ animated: Bool) {
super.viewDidDisappear(animated)
scrollView.contentInset.bottom = 0
}


private func registerNotifications() {
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}


@objc private func keyboardWillShow(notification: NSNotification){
guard let keyboardFrame = notification.userInfo![UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
scrollView.contentInset.bottom = view.convert(keyboardFrame.cgRectValue, from: nil).size.height
}


@objc private func keyboardWillHide(notification: NSNotification){
scrollView.contentInset.bottom = 0
}
小开

From the answer by Sudheer Palchuri, converted for Swift 4.

In ViewDidLoad, register the notifications: 

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

And then:

// MARK: - Keyboard Delegates
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}


@objc func keyboardWillShow(notification:NSNotification){


var userInfo = notification.userInfo!
var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
keyboardFrame = self.view.convert(keyboardFrame, from: nil)


var contentInset:UIEdgeInsets = self.scrollView.contentInset
contentInset.bottom = keyboardFrame.size.height
self.scrollView.contentInset = contentInset
}


@objc func keyboardWillHide(notification:NSNotification){


let contentInset:UIEdgeInsets = UIEdgeInsets.zero
self.scrollView.contentInset = contentInset
}
小开

In Swift4, just add the following extension.

extension UIViewController {


func setupViewResizerOnKeyboardShown() {
NotificationCenter.default.addObserver(self,
selector: #selector(self.keyboardWillShowForResizing),
name:
Notification.Name.UIKeyboardWillShow,
object: nil)
NotificationCenter.default.addObserver(self,
selector: #selector(self.keyboardWillHideForResizing),
name: Notification.Name.UIKeyboardWillHide,
object: nil)
}


@objc func keyboardWillShowForResizing(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue,
let window = self.view.window?.frame {
// We're not just minusing the kb height from the view height because
// the view could already have been resized for the keyboard before
self.view.frame = CGRect(x: self.view.frame.origin.x,
y: self.view.frame.origin.y,
width: self.view.frame.width,
height: window.origin.y + window.height - keyboardSize.height)
} else {
debugPrint("We're showing the keyboard and either the keyboard size or window is nil: panic widely.")
}
}


@objc func keyboardWillHideForResizing(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let viewHeight = self.view.frame.height
self.view.frame = CGRect(x: self.view.frame.origin.x,
y: self.view.frame.origin.y,
width: self.view.frame.width,
height: viewHeight + keyboardSize.height)
} else {
debugPrint("We're about to hide the keyboard and the keyboard size is nil. Now is the rapture.")
}
}
}
小开

for Swift 4.0

In ViewDidLoad

// setup keyboard event
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)

Add below observer methods which does the automatic scrolling when keyboard appears.

@objc func keyboardWillShow(notification:NSNotification){
var userInfo = notification.userInfo!
var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
keyboardFrame = self.view.convert(keyboardFrame, from: nil)


var contentInset:UIEdgeInsets = self.ui_scrollView.contentInset
contentInset.bottom = keyboardFrame.size.height
ui_scrollView.contentInset = contentInset
}


@objc func keyboardWillHide(notification:NSNotification){


let contentInset:UIEdgeInsets = UIEdgeInsets.zero
ui_scrollView.contentInset = contentInset
}
小开

In case anyone is looking for Objective-C code for this solution:

- (void)keyboardWasShown:(NSNotification *)notification {
NSDictionary* info = [notification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
UIEdgeInsets contentInsets = baseScrollView.contentInset;
contentInsets.bottom = kbSize.height;
baseScrollView.contentInset = contentInsets;
}


- (void)keyboardWillBeHidden:(NSNotification *)notification {
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
baseScrollView.contentInset = contentInsets;
[baseScrollView endEditing:YES];
}
小开

Swift 5 Only adjust ScrollView when TextField is hidden by keyboard (for multiple TextFields)

Add / Remove Observers: 

override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}


override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
NotificationCenter.default.removeObserver(self)
}

Keep track of these values so you can return to your original position:

var scrollOffset : CGFloat = 0
var distance : CGFloat = 0

Adjust ScrollView contentOffset depending on TextField Location:

@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {


var safeArea = self.view.frame
safeArea.size.height += scrollView.contentOffset.y
safeArea.size.height -= keyboardSize.height + (UIScreen.main.bounds.height*0.04) // Adjust buffer to your liking


// determine which UIView was selected and if it is covered by keyboard


let activeField: UIView? = [textFieldA, textViewB, textFieldC].first { $0.isFirstResponder }
if let activeField = activeField {
if safeArea.contains(CGPoint(x: 0, y: activeField.frame.maxY)) {
print("No need to Scroll")
return
} else {
distance = activeField.frame.maxY - safeArea.size.height
scrollOffset = scrollView.contentOffset.y
self.scrollView.setContentOffset(CGPoint(x: 0, y: scrollOffset + distance), animated: true)
}
}
// prevent scrolling while typing


scrollView.isScrollEnabled = false
}
}
@objc func keyboardWillHide(notification: NSNotification) {
if distance == 0 {
return
}
// return to origin scrollOffset
self.scrollView.setContentOffset(CGPoint(x: 0, y: scrollOffset), animated: true)
scrollOffset = 0
distance = 0
scrollView.isScrollEnabled = true
}

Make sure to use [UIResponder.keyboardFrameEndUserInfoKey] to get the proper keyboard height the first time.

小开

In my situation it was

ScrollView --> TableView --> TableViewCell

So I had to get y position in relative to keyboard frame and check if keyboard y position and my active field y position was intersecting or not

   @objc func keyboardWillShow(_ notification: Foundation.Notification) {


var userInfo = notification.userInfo!
var keyboardFrame:CGRect = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
keyboardFrame = self.view.convert(keyboardFrame, from: nil)


var contentInset:UIEdgeInsets = self.scrollView!.contentInset
contentInset.bottom = keyboardFrame.size.height
let loc = self.activeTextField?.convert(activeTextField!.bounds, to: self.view)


if keyboardFrame.origin.y <  loc!.origin.y {
self.scrollView?.contentOffset = CGPoint.init(x: (self.scrollView?.contentOffset.x)!, y: loc!.origin.y)
}


if self.scrollView?.contentInset.bottom == 0 {
self.scrollView?.contentInset = contentInset
}


}
小开

This is a refinement on Zachary Probst solution posted above. I ran into a few issues with his solution and fixed it and enhanced it a bit.

This version does not need to pass in a list of UITextView controls. It finds the first responder in the current view. It also handles UITextView controls at any level in the View hierarchy.

I think his safeArea calculation wasn't quite right scrollView.contentOffset.y needed sign changed. It didn't show up if it was not scrolled. This fixed incremental scrolling. It might have been from other changes I made.

This works if the user jumps around to other UITextViews while the keyboard is up.

This is a Base Class I use for a bunch of ViewControllers. The inherited ViewController just needs to set the UIScrollViewer which activates this code behavior.

class ThemeAwareViewController: UIViewController
{
var scrollViewForKeyBoard: UIScrollView? = nil
var saveOffsetForKeyBoard: CGPoint?
    

func findViewThatIsFirstResponder(view: UIView) -> UIView?
{
if view.isFirstResponder {
return view
}


for subView in view.subviews {
if let hit = findViewThatIsFirstResponder(view: subView) {
return hit
}
}


return nil
}
    

@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if let scrollView = scrollViewForKeyBoard {
                

var safeArea = self.view.frame
safeArea.size.height -= scrollView.contentOffset.y
safeArea.size.height -= keyboardSize.height
safeArea.size.height -= view.safeAreaInsets.bottom
                

let activeField: UIView? = findViewThatIsFirstResponder(view: view)
                

if let activeField = activeField {
// This line had me stumped for a while (I was passing in .frame)
let activeFrameInView = view.convert(activeField.bounds, from: activeField)
let distance = activeFrameInView.maxY - safeArea.size.height
if saveOffsetForKeyBoard == nil {
saveOffsetForKeyBoard = scrollView.contentOffset
}
scrollView.setContentOffset(CGPoint(x: 0, y: distance), animated: true)
}
}
}
}
    

@objc func keyboardWillHide(notification: NSNotification) {
guard let restoreOffset = saveOffsetForKeyBoard else {
return
}
if let scrollView = scrollViewForKeyBoard {
scrollView.setContentOffset(restoreOffset, animated: true)
self.saveOffsetForKeyBoard = nil
}
}
}
小开

There is a simple solution here


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