I am trying to make an app where the user could drag a finger on top of multiple buttons and get some actions for each button.
There was a similar question from a while back but when I tried to use CGRectContainsPoint(button.frame, point) it said it was replaced with button.frame.contains(point) but this didn’t seem to work for me. Here is a link to the Photo
What I have done so far:
var buttonArray:NSMutableArray!
override func viewDidLoad()
{
super.viewDidLoad()
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(panGestureMethod(_:)))
a1.addGestureRecognizer(panGesture)
a2.addGestureRecognizer(panGesture)
}
#objc func panGestureMethod(_ gesture: UIPanGestureRecognizer) {
if gesture.state == UIGestureRecognizer.State.began {
buttonArray = NSMutableArray()
}
let pointInView = gesture.location(in: gesture.view)
if !buttonArray.contains(a1!) && a1.frame.contains(pointInView) {
buttonArray.add(a1!)
a1Tapped(a1)
}
else if !buttonArray.contains(a2!) && a2.frame.contains(pointInView) {
buttonArray.add(a2!)
a2Tapped(a2)
}
The code did run fine but when I tried to activate the drag nothing happened. Any tips?
You want behavior similar to the system keyboard I assume? CGRectContainsPoint is not deprecated: See the docs. In Swift it's written like frame.contains().
When dealing with rects and points you have to make sure both are translated to the same coordinate system first. To do so you can use the convert to/from methods on UIView: See (the docs).
In your case smth. like the following should work (first translate button frames, then check if the point is inside):
func touchedButtonForGestureRecognizer(_ gesture: UIPanGestureRecognizer) -> UIView? {
let pointInView = gesture.location(in: gesture.view)
for (button in buttonArray) {
let rect = gesture.view.convert(button.frame from:button.superview)
if (rect.contains(pointInView)) {
return button
}
}
return nil
}
I have function which creates a drag line to connect 2 buttons to each other. This works fine but if some buttons overlap each other, it will select both if I drag over where they overlap. I only want to connect the top button.
I think the issue is with the sender.location selecting layers on top and below. Is there a way to tell the sender.location to only select the top view? Thanks for any input and direction
func addPanReconiser(view: UIView){
let pan = UIPanGestureRecognizer(target: self, action: #selector(DesignViewController.panGestureCalled(_:)))
view.addGestureRecognizer(pan)
}
#objc func panGestureCalled(_ sender: UIPanGestureRecognizer) {
let currentPanPoint = sender.location(in: self.view)
switch sender.state {
case .began:
panGestureStartPoint = currentPanPoint
self.view.layer.addSublayer(lineShape)
case .changed:
let linePath = UIBezierPath()
linePath.move(to: panGestureStartPoint)
linePath.addLine(to: currentPanPoint)
lineShape.path = linePath.cgPath
lineShape.path = CGPath.barbell(from: panGestureStartPoint, to: currentPanPoint, barThickness: 2.0, bellRadius: 6.0)
for button in buttonArray {
let point = sender.location(in: button)
if button.layer.contains(point) {
button.layer.borderWidth = 4
button.layer.borderColor = UIColor.blue.cgColor
} else {
button.layer.borderWidth = 0
button.layer.borderColor = UIColor.clear.cgColor
}
}
case .ended:
for button in buttonArray {
let point = sender.location(in: button)
if button.layer.contains(point){
//DO my Action here
lineShape.path = nil
lineShape.removeFromSuperlayer()
}
}
default: break
}
}
}
Note: some of the lines of codes are from custom extensions. I kept them in as they were self explanatory.
Thanks for the help
There is a way to walk around. It seems like you simply want your gesture end up at one button above all the others, thus by adding a var outside the loop and each time a button picked, comparing with the var of its level at z.
case .ended:
var pickedButton: UIButton?
for button in buttonArray {
let point = sender.location(in: button)
if button.layer.contains(point){
if pickedButton == nil {
pickedButton = button
} else {
if let parent = button.superView, parent.subviews.firstIndex(of: button) > parent.subviews.firstIndex(of: pickedButton!) {
pickedButton = button
}
}
}
}
//DO my Action with pickedButton here
lineShape.path = nil
lineShape.removeFromSuperlayer()
A UIView has a property called subViews where elements with higher indexes are in front of the ones with lower indexes. For instance, subView at index 1 is in front of subView with index 0.
That being said, to get the button that's on top, you should sort your buttonArray the same way subViews property of UIView is organized. Assuming that your buttons are all siblings of the same UIView (this might not be necessarily the case, but you can tweak them so you get them sorted correctly):
var buttonArray = view.subviews.compactMap { $0 as? UIButton }
Thus, keeping your buttonArray sorted that way, the button you want is the one that contains let point = sender.location(in: button) with higher index in the array.
apologies if this is a stupid question. I can't seem to get my slider to update its value as its being interacted with. (I'm going to point everyone to the very last method in this long code)
class CustomSlider: UISlider {
override func trackRect(forBounds bounds: CGRect) -> CGRect {
var rect = super.trackRect(forBounds: bounds)
rect.size.height = 7
return rect
}
}
class FactionButton: CustomSlider {
var factionSlider = CustomSlider(frame: CGRect(x: 15, y: 542, width: 386, height: 57))
func factionBalanceSlider(){
factionSlider.minimumValueImage = #imageLiteral(resourceName: "Alliance Slider")
factionSlider.maximumValueImage = #imageLiteral(resourceName: "Horde Slider")
factionSlider.setThumbImage(#imageLiteral(resourceName: "Thumb Image"), for: .normal)
factionSlider.minimumTrackTintColor = UIColor(red:0.08, green:0.33, blue:0.69, alpha:0.8)
factionSlider.maximumTrackTintColor = UIColor(red:1.00, green:0.00, blue:0.00, alpha:0.59)
factionSlider.setValue(0.5, animated: true)
factionSlider.isContinuous = false
factionSlider.addTarget(self, action: #selector(recordFactionBalance(sender:)), for: .valueChanged)
}
func getSlider() -> CustomSlider {
return factionSlider
}
override func trackRect(forBounds bounds: CGRect) -> CGRect {
var customBounds = super.trackRect(forBounds: bounds)
customBounds.size.height = 10
return customBounds
}
#objc func recordFactionBalance(sender: CustomSlider){
//also calculates balance and adds it into the quiz data
print("hi")
print(sender.value) //It's this part that doesn't work
}
}
It's this bit nearest to the bottom that has the issue. (Everything else is fine) The action function doesn't seem to be triggered at all, even when I'm interacting with it. Neither print statements are being executed. Any ideas why?
Cheers
From the getSlider(), i can guess you are using this class as a utility to get the CustomSlider. So, i suspect you are adding the slider to the view as below,
let container = FactionButton()
container.factionBalanceSlider()
let slider = container.getSlider()
self.view.addSubview(slider)
If you will not add the container to the view which is set as the receiver for .valueChange event so it will not get any event. To receive events you also need to add the container in the view as below,
self.view.addSubview(container)
I'm attempting to add support for Voice Over accessibility in a puzzle game which has a fixed board. However, I'm having trouble getting UIAccessibilityElements to show up.
Right now I'm overriding accessibilityElementAtIndex, accessibilityElementCount and indexOfAccessibilityElement in my SKScene.
They are returning an array of accessible elements as such:
func loadAccessibleElements()
{
self.isAccessibilityElement = false
let pieces = getAllPieces()
accessibleElements.removeAll(keepCapacity: false)
for piece in pieces
{
let element = UIAccessibilityElement(accessibilityContainer: self.usableView!)
element.accessibilityFrame = piece.getAccessibilityFrame()
element.accessibilityLabel = piece.getText()
element.accessibilityTraits = UIAccessibilityTraitButton
accessibleElements.append(element)
}
}
Where piece is a subclass of SKSpriteNode and getAccessibilityFrame is defined:
func getAccessibilityFrame() -> CGRect
{
return parentView!.convertRect(frame, toView: nil)
}
Right now one (wrongly sized) accessibility element seems to appear on the screen in the wrong place.
Could someone point me in the right direction?
Many thanks
EDIT:
I've tried a hack-ish work around by placing a UIView over the SKView with UIButton elements in the same location as the SKSpriteNodes. However, accessibility still doesn't want to work. The view is loaded as such:
func loadAccessibilityView()
{
view.isAccessibilityElement = false
view.accessibilityElementsHidden = false
skView.accessibilityElementsHidden = false
let accessibleSubview = UIView(frame: view.frame)
accessibleSubview.userInteractionEnabled = true
accessibleSubview.isAccessibilityElement = false
view.addSubview(accessibleSubview)
view.bringSubviewToFront(accessibleSubview)
let pieces = (skView.scene! as! GameScene).getAllPieces()
for piece in pieces
{
let pieceButton = UIButton(frame: piece.getAccessibilityFrame())
pieceButton.isAccessibilityElement = true
pieceButton.accessibilityElementsHidden = false
pieceButton.accessibilityTraits = UIAccessibilityTraitButton
pieceButton.setTitle(piece.getText(), forState: UIControlState.Normal)
pieceButton.setBackgroundImage(UIImage(named: "blue-button"), forState: UIControlState.Normal)
pieceButton.alpha = 0.2
pieceButton.accessibilityLabel = piece.getText()
pieceButton.accessibilityFrame = pieceButton.frame
pieceButton.addTarget(self, action: Selector("didTap:"), forControlEvents: UIControlEvents.TouchUpInside)
accessibleSubview.addSubview(pieceButton)
}
UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification, nil)
}
The buttons are placed correctly, however accessibility just isn't working at all. Something seems to be preventing it from working.
I've searched in vain for a description of how to implement VoiceOver in Swift using SpriteKit, so I finally figured out how to do it. Here's some working code that converts a SKNode to an accessible pushbutton when added to a SKScene class:
// Add the following code to a scene where you want to make the SKNode variable named “leave” an accessible button
// leave must already be initialized and added as a child of the scene, or a child of other SKNodes in the scene
// screenHeight must already be defined as the height of the device screen, in points
// Accessibility
private var accessibleElements: [UIAccessibilityElement] = []
private func nodeToDevicePointsFrame(node: SKNode) -> CGRect {
// first convert from frame in SKNode to frame in SKScene's coordinates
var sceneFrame = node.frame
sceneFrame.origin = node.scene!.convertPoint(node.frame.origin, fromNode: node.parent!)
// convert frame from SKScene coordinates to device points
// sprite kit scene origin is in lower left, accessibility device screen origin is at upper left
// assumes scene is initialized using SKSceneScaleMode.Fill using dimensions same as device points
var deviceFrame = sceneFrame
deviceFrame.origin.y = CGFloat(screenHeight-1) - (sceneFrame.origin.y + sceneFrame.size.height)
return deviceFrame
}
private func initAccessibility() {
if accessibleElements.count == 0 {
let accessibleLeave = UIAccessibilityElement(accessibilityContainer: self.view!)
accessibleLeave.accessibilityFrame = nodeToDevicePointsFrame(leave)
accessibleLeave.accessibilityTraits = UIAccessibilityTraitButton
accessibleLeave.accessibilityLabel = “leave” // the accessible name of the button
accessibleElements.append(accessibleLeave)
}
}
override func didMoveToView(view: SKView) {
self.isAccessibilityElement = false
leave.isAccessibilityElement = true
}
override func willMoveFromView(view: SKView) {
accessibleElements = []
}
override func accessibilityElementCount() -> Int {
initAccessibility()
return accessibleElements.count
}
override func accessibilityElementAtIndex(index: Int) -> AnyObject? {
initAccessibility()
if (index < accessibleElements.count) {
return accessibleElements[index] as AnyObject
} else {
return nil
}
}
override func indexOfAccessibilityElement(element: AnyObject) -> Int {
initAccessibility()
return accessibleElements.indexOf(element as! UIAccessibilityElement)!
}
Accessibility frames are defined in the fixed physical screen coordinates, not UIView coordinates, and transforming between them is kind of tricky.
The device origin is the lower left of the screen, with X up, when the device is in landscape right mode.
It's a pain converting, I've no idea why Apple did it that way.
I've seen posts around here that suggest that UIScrollViews should automatically scroll if a subview UITextField becomes the first responder; however, I can't figure out how to get this to work.
What I have is a UIViewController that has a UIScrollView and within the UIScrollView there are multiple textfields.
I know how to do this manually if necessary; however, from what I've been reading, it seems possible to have it autoscroll. Help please.
I hope this example will help you
You can scroll to any point by this code.
scrollView.contentOffset = CGPointMake(0,0);
So if you have textfield, it must have some x,y position on view, so you can use
CGPoint point = textfield.frame.origin ;
scrollView.contentOffset = point
This should do the trick,
But if you don't know when to call this code, so you should learn UITextFieldDelegate methods
Implement this method in your code
- (void)textFieldDidBeginEditing:(UITextField *)textField {
// Place Scroll Code here
}
I hope you know how to use delegate methods.
I know this question has already been answered, but I thought I would share the code combination that I used from #Adeel and #Basil answer, as it seems to work perfectly for me on iOS 9.
-(void)textFieldDidBeginEditing:(UITextField *)textField {
// Scroll to the text field so that it is
// not hidden by the keyboard during editing.
[scroll setContentOffset:CGPointMake(0, (textField.superview.frame.origin.y + (textField.frame.origin.y))) animated:YES];
}
-(void)textFieldDidEndEditing:(UITextField *)textField {
// Remove any content offset from the scroll
// view otherwise the scroll view will look odd.
[scroll setContentOffset:CGPointMake(0, 0) animated:YES];
}
I also used the animated method, it makes for a much smoother transition.
Here is the Swift 4 update to #Supertecnoboff's answer. It worked great for me.
func textFieldDidBeginEditing(_ textField: UITextField) {
scroll.setContentOffset(CGPoint(x: 0, y: (textField.superview?.frame.origin.y)!), animated: true)
}
func textFieldDidEndEditing(_ textField: UITextField) {
scroll.setContentOffset(CGPoint(x: 0, y: 0), animated: true)
}
Make sure to extend UITextFieldDelegate and set the textfields' delegate to self.
There is nothing you have to do manually. It is the default behavior. There are two possibilities as to why you are not seeing the behavior
The most likely reason is that the keyboard is covering your UITextField. See below for solution
The other possibility is that you have another UIScrollView somewhere in the view hierarchy between the UITextField and the UIScrollView that you want to auto scroll. This is less likely but can still cause problems.
For #1, you want to implement something similar to Apple's recommendations for Moving Content That Is Located Under the Keyboard. Note that the code provided by Apple does not account for rotation. For improvements on their code, check out this blog post's implementation of the keyboardDidShow method that properly translates the keyboard's frame using the window.
- (void)textFieldDidBeginEditing:(UITextField *)textField {
CGRect rect = [textField bounds];
rect = [textField convertRect:rect toView:self.scrollView];
rect.origin.x = 0 ;
rect.origin.y -= 60 ;
rect.size.height = 400;
[self.scrollView scrollRectToVisible:rect animated:YES];
}
You can use this function for autoScroll of UITextField
on UITextFieldDelegate
- (void)textFieldDidBeginEditing:(UITextField *)textField {
[self autoScrolTextField:textField onScrollView:self.scrollView];
}
- (void) autoScrolTextField: (UITextField *) textField onScrollView: (UIScrollView *) scrollView {
float slidePoint = 0.0f;
float keyBoard_Y_Origin = self.view.bounds.size.height - 216.0f;
float textFieldButtomPoint = textField.superview.frame.origin.y + (textField.frame.origin.y + textField.frame.size.height);
if (keyBoard_Y_Origin < textFieldButtomPoint - scrollView.contentOffset.y) {
slidePoint = textFieldButtomPoint - keyBoard_Y_Origin + 10.0f;
CGPoint point = CGPointMake(0.0f, slidePoint);
scrollView.contentOffset = point;
}
EDIT:
Im now using IQKeyboardManager
Kudos to the developer of this, you need to try this.
Solution
extension UIScrollView {
func scrollVerticallyToFirstResponderSubview(keyboardFrameHight: CGFloat) {
guard let firstResponderSubview = findFirstResponderSubview() else { return }
scrollVertically(toFirstResponder: firstResponderSubview,
keyboardFrameHight: keyboardFrameHight, animated: true)
}
private func scrollVertically(toFirstResponder view: UIView,
keyboardFrameHight: CGFloat, animated: Bool) {
let scrollViewVisibleRectHeight = frame.height - keyboardFrameHight
let maxY = contentSize.height - scrollViewVisibleRectHeight
if contentOffset.y >= maxY { return }
var point = view.convert(view.bounds.origin, to: self)
point.x = 0
point.y -= scrollViewVisibleRectHeight/2
if point.y > maxY {
point.y = maxY
} else if point.y < 0 {
point.y = 0
}
setContentOffset(point, animated: true)
}
}
extension UIView {
func findFirstResponderSubview() -> UIView? { getAllSubviews().first { $0.isFirstResponder } }
func getAllSubviews<T: UIView>() -> [T] { UIView.getAllSubviews(from: self) as [T] }
class func getAllSubviews<T: UIView>(from parenView: UIView) -> [T] {
parenView.subviews.flatMap { subView -> [T] in
var result = getAllSubviews(from: subView) as [T]
if let view = subView as? T { result.append(view) }
return result
}
}
}
Full Sample
Do not forget to paste the Solution code here
import UIKit
class ViewController: UIViewController {
private weak var scrollView: UIScrollView!
private lazy var keyboard = KeyboardNotifications(notifications: [.willHide, .willShow], delegate: self)
override func viewDidLoad() {
super.viewDidLoad()
let scrollView = UIScrollView()
view.addSubview(scrollView)
scrollView.translatesAutoresizingMaskIntoConstraints = false
scrollView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
scrollView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor).isActive = true
scrollView.rightAnchor.constraint(equalTo: view.safeAreaLayoutGuide.rightAnchor).isActive = true
scrollView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
scrollView.contentSize = CGSize(width: view.frame.width, height: 1000)
scrollView.isScrollEnabled = true
scrollView.indicatorStyle = .default
scrollView.backgroundColor = .yellow
scrollView.keyboardDismissMode = .interactive
self.scrollView = scrollView
addTextField(y: 20)
addTextField(y: 300)
addTextField(y: 600)
addTextField(y: 950)
}
private func addTextField(y: CGFloat) {
let textField = UITextField()
textField.borderStyle = .line
scrollView.addSubview(textField)
textField.translatesAutoresizingMaskIntoConstraints = false
textField.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: y).isActive = true
textField.leftAnchor.constraint(equalTo: scrollView.leftAnchor, constant: 44).isActive = true
textField.widthAnchor.constraint(equalToConstant: 120).isActive = true
textField.heightAnchor.constraint(equalToConstant: 44).isActive = true
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
keyboard.isEnabled = true
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
keyboard.isEnabled = false
}
}
extension ViewController: KeyboardNotificationsDelegate {
func keyboardWillShow(notification: NSNotification) {
guard let userInfo = notification.userInfo as? [String: Any],
let keyboardFrame = userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else { return }
scrollView.contentInset.bottom = keyboardFrame.height
scrollView.scrollVerticallyToFirstResponderSubview(keyboardFrameHight: keyboardFrame.height)
}
func keyboardWillHide(notification: NSNotification) {
scrollView.contentInset.bottom = 0
}
}
/// Solution
extension UIScrollView {
func scrollVerticallyToFirstResponderSubview(keyboardFrameHight: CGFloat) {
guard let firstResponderSubview = findFirstResponderSubview() else { return }
scrollVertically(toFirstResponder: firstResponderSubview,
keyboardFrameHight: keyboardFrameHight, animated: true)
}
private func scrollVertically(toFirstResponder view: UIView,
keyboardFrameHight: CGFloat, animated: Bool) {
let scrollViewVisibleRectHeight = frame.height - keyboardFrameHight
let maxY = contentSize.height - scrollViewVisibleRectHeight
if contentOffset.y >= maxY { return }
var point = view.convert(view.bounds.origin, to: self)
point.x = 0
point.y -= scrollViewVisibleRectHeight/2
if point.y > maxY {
point.y = maxY
} else if point.y < 0 {
point.y = 0
}
setContentOffset(point, animated: true)
}
}
extension UIView {
func findFirstResponderSubview() -> UIView? { getAllSubviews().first { $0.isFirstResponder } }
func getAllSubviews<T: UIView>() -> [T] { UIView.getAllSubviews(from: self) as [T] }
class func getAllSubviews<T: UIView>(from parenView: UIView) -> [T] {
parenView.subviews.flatMap { subView -> [T] in
var result = getAllSubviews(from: subView) as [T]
if let view = subView as? T { result.append(view) }
return result
}
}
}
// https://stackoverflow.com/a/42600092/4488252
import Foundation
protocol KeyboardNotificationsDelegate: class {
func keyboardWillShow(notification: NSNotification)
func keyboardWillHide(notification: NSNotification)
func keyboardDidShow(notification: NSNotification)
func keyboardDidHide(notification: NSNotification)
}
extension KeyboardNotificationsDelegate {
func keyboardWillShow(notification: NSNotification) {}
func keyboardWillHide(notification: NSNotification) {}
func keyboardDidShow(notification: NSNotification) {}
func keyboardDidHide(notification: NSNotification) {}
}
class KeyboardNotifications {
fileprivate var _isEnabled: Bool
fileprivate var notifications: [NotificationType]
fileprivate weak var delegate: KeyboardNotificationsDelegate?
fileprivate(set) lazy var isKeyboardShown: Bool = false
init(notifications: [NotificationType], delegate: KeyboardNotificationsDelegate) {
_isEnabled = false
self.notifications = notifications
self.delegate = delegate
}
deinit { if isEnabled { isEnabled = false } }
}
// MARK: - enums
extension KeyboardNotifications {
enum NotificationType {
case willShow, willHide, didShow, didHide
var selector: Selector {
switch self {
case .willShow: return #selector(keyboardWillShow(notification:))
case .willHide: return #selector(keyboardWillHide(notification:))
case .didShow: return #selector(keyboardDidShow(notification:))
case .didHide: return #selector(keyboardDidHide(notification:))
}
}
var notificationName: NSNotification.Name {
switch self {
case .willShow: return UIResponder.keyboardWillShowNotification
case .willHide: return UIResponder.keyboardWillHideNotification
case .didShow: return UIResponder.keyboardDidShowNotification
case .didHide: return UIResponder.keyboardDidHideNotification
}
}
}
}
// MARK: - isEnabled
extension KeyboardNotifications {
private func addObserver(type: NotificationType) {
NotificationCenter.default.addObserver(self, selector: type.selector, name: type.notificationName, object: nil)
}
var isEnabled: Bool {
set {
if newValue {
for notificaton in notifications { addObserver(type: notificaton) }
} else {
NotificationCenter.default.removeObserver(self)
}
_isEnabled = newValue
}
get { _isEnabled }
}
}
// MARK: - Notification functions
extension KeyboardNotifications {
#objc func keyboardWillShow(notification: NSNotification) {
delegate?.keyboardWillShow(notification: notification)
isKeyboardShown = true
}
#objc func keyboardWillHide(notification: NSNotification) {
delegate?.keyboardWillHide(notification: notification)
isKeyboardShown = false
}
#objc func keyboardDidShow(notification: NSNotification) {
isKeyboardShown = true
delegate?.keyboardDidShow(notification: notification)
}
#objc func keyboardDidHide(notification: NSNotification) {
isKeyboardShown = false
delegate?.keyboardDidHide(notification: notification)
}
}
If you have multiple textfields say Textfield1, Textfield2, Textfield3 and you want to scroll the scrollview along the y-axis when textfield2 becomes first responder:
if([Textfield2 isFirstResponder])
{
scrollView.contentOffset = CGPointMake(0,yourY);
}
As Michael McGuire mentioned in his point #2 above, the system's default behavior misbehaves when the scroll view contains another scroll view between the text field and the scroll view. I've found that the misbehavior also occurs when there's a scroll view merely next to the text field (both embedded in the scroll view that needs to be adjusted to bring the text field into view when the text field wants to start editing. This is on iOS 12.1.
But my solution is different from the above. In my top-level scroll view, which is sub-classed so I can add properties and override methods, I override scrollRectToVisible:animated:. It simply calls its [super scrollRectToVisible:animated:] unless there's a property set that tells it to adjust the rect passed in, which is the frame of the text field. When the property is non-nil, it is a reference to the UITextField in question, and the rect is adjusted so that the scroll view goes further than the system thought it would. So I put this in the UIScrollView's sub-classed header file:
#property (nullable) UITextField *textFieldToBringIntoView;
(with appropriate #synthesize textFieldToBringIntoView; in the implementation. Then I added this override method to the implementation:
- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)how
{
if (textFieldToBringIntoView) {
// Do whatever mucking with `rect`'s origin needed to make it visible
// based on context or its spatial relationship with the other
// view that the system is getting confused by.
textFieldToBringIntoView = nil; // Go back to normal
}
[super scrollRectToVisible:rect animated:how];
}
In the delegate method for the UITextField for when it's about to begin editing, just set textFieldToBringIntoView to the textField in question:
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
// Ensure it scrolls into view so that keyboard doesn't obscure it
// The system is about to call |scrollRectIntoView:| for the scrolling
// superview, but the system doesn't get things right in certain cases.
UIScrollView *parent = (UIScrollView *)textField.superview;
// (or figure out the parent UIScrollView some other way)
// Tell the override to do something special just once
// based on this text field's position in its parent's scroll view.
parent.textFieldToBringIntoView = textField;
// The override function will set this back to nil
return(YES);
}
It seems to work. And if Apple fixes their bug, it seems like it might still work (fingers crossed).
Building off of Vasily Bodnarchuk's answer I created a gist with a simple protocol that you can implement and it'll do it all for you.
All you need to do is call registerAsTextDisplacer()
I created a BaseViewController in my project and made that implement it
https://gist.github.com/CameronPorter95/cb68767f5f8052fdc70293c167e9430e
Other solutions I saw, let you set the offset to the origin of the textField but this makes the scroller view go beyond it bounds.
I did this adjustment to the offset instead to not go beyond the bottom nor the top offsets.
Set the keyboardHeightConstraint to the bottom of the page.
When the keyboard shows, update its constraint's constant to negative the keyboard height.
Then scroll to the responderField as we will show below.
#IBOutlet var keyboardHeightConstraint: NSLayoutConstraint?
var responderField: String?
#objc func keyboardNotification(notification: NSNotification) {
guard let keyboardValue = notification.userInfo [UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
let keyboardHeight = keyboardValue.cgRectValue.height
keyboardHeightConstraint?.constant = -keyboardHeight
scroll(field: responderField!)
}
func textFieldDidBeginEditing(_ textField: UITextField) {
responderField = textField
}
Now we want to make sure we do not scroll greater than the bottom offset nor less than the top offset.
At the same time, we want to calculate the offset of the field's maxY value.
To do that, we subtract the scrollView.bounds.size.height from the maxY value.
let targetOffset = field.frame.maxY - scrollView.bounds.size.height
I found it nicer to scroll an extra distance of the keyboard height, but you could neglect that if you want to scroll right below the field.
let targetOffset = keyboardHeight + field.frame.maxY - scrollView.bounds.size.height
Remember to add the scrollView.contentInset.bottom if you have the tab bar visible.
func scroll(field: UITextField) {
guard let keyboardConstraintsConstant = keyboardHeightConstraint?.constant else { return }
let keyboardHeight = -keyboardConstraintsConstant
view.layoutIfNeeded()
let bottomOffset = scrollView.contentSize.height - scrollView.bounds.size.height + scrollView.contentInset.bottom
let topOffset = -scrollView.safeAreaInsets.top
let targetOffset = keyboardHeight + field.frame.maxY + scrollView.contentInset.bottom - scrollView.bounds.size.height
let adjustedOffset = targetOffset > bottomOffset ? bottomOffset : (targetOffset < topOffset ? topOffset : targetOffset)
scrollView.setContentOffset(CGPoint(x: 0, y: adjustedOffset), animated: true)
}
If you have scrollView and tableView with invalidating intrinsicContentSize as the subview, you can disable tableView scrolling in storyboard or set tableView.isScrollEnabled to false in code.