As you can see in the image below I have a video which covers almost the entire screen. I want the video to play/stop whenever one taps on it. The code works almost perfectly fine, the thing is the class in which I call the defInteractions function also contains the booked and comments subview which can also be found below. Consequently, the video also plays/stops when one taps these areas which I don't want.
The UITapGestureRecognizer triggering the function to play/pause the video:
//set interactions
func defInteractions (){
//singletap
let singleTap = UITapGestureRecognizer(target: self, action: #selector(singleTapDetected(_:)))
singleTap.numberOfTapsRequired = 1
//singleTap.cancelsTouchesInView = false
//controlsContainerView
controlsContainerView.addGestureRecognizer(singleTap)
}
//define type
var player: AVPlayer?
//set playing to false
var isPlaying: Bool = false
func singleTapDetected(_ sender: UITapGestureRecognizer) {
//play or pause
if(!isPlaying){
//play
player?.play()
isPlaying = true
}
else{
//pause
player?.pause()
isPlaying = false
}
}
Each subview looks basically like this:
//create controls container view
let comments: UIView = {
//set properties of controls container view
let commentrect = CGRect(x: viewWidth / 2, y: viewHeight - 110, width: viewWidth / 2, height: 50)
let entireCommentView = UILabel(frame: commentrect)
entireCommentView.translatesAutoresizingMaskIntoConstraints = true
entireCommentView.backgroundColor = .white
entireCommentView.font = UIFont(name: "HelveticaNeue", size: 20)
entireCommentView.text = "3 comments"
entireCommentView.textColor = .black
entireCommentView.textAlignment = .center
return entireCommentView
}()
In the override they are added as subviews. I tried setting isUserInteractionEnabled to false in the individual subviews (e.g. comments: entireCommentView.isUserInteractionEnabled = false) which didn't work and don't know how to achieve my goal. Can someone help me? Can I exclude these subviews from my target in the UITapGestureRecognizer recognizer.
[
EDIT (Result of first answer):
Modify the singleTapDetected to return if the tap is in any of the top or bottom UIViews.
func singleTapDetected(_ sender: UITapGestureRecognizer) {
let view = sender.view
let loc = sender.location(in: controlsContainerView)
if let subview = view?.hitTest(loc, with: nil) {
if subview == entireCommentView || subview == bookedView {
return
}
}
//play or pause
player?.rate != 0 && player?.error == nil ? player?.pause() : player?.play
}
Alternatively, you can have your UIViewController adopt the UIGestureRecognizerDelegate protocol and call the below method for checking the view. Inside this method, check your view against touch.view and return the appropriate bool (Yes/No). Something like this:
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
return !touch.view?.isDescendant(of: controlsContainerView)
}
You should define the likes and booked variables as property of the UIView subclass itself, to make them visible to your singleTapDetected(_:) method
Related
I am trying to build the iOS app that will track the user interactions with screen, what user clicks and what gestures user does. My plan was to create it as a OverlayView that could be put over any iOS app in a form of a View, without breaking any previous functionalities. I am currently testing it with the button that has another View on top of it.
Currently I am managing to either register click in top-layer View and track the gesture, or in button action function, but couldn't manage to get them both triggered at once.
override func viewDidLoad() {
super.viewDidLoad()
let button = UIButton(frame: CGRect(x: 100, y: 100, width: 100, height: 50))
button.backgroundColor = .green
button.addTarget(self, action: #selector(buttonClicked), for: .touchUpInside)
self.view.addSubview(button)
let topLayerView = UIView(frame: CGRect(x: 0, y: 0, width: 400, height: 900))
self.view.addSubview(topLayerView)
topLayerView.backgroundColor = .yellow
self.view.bringSubviewToFront(topLayerView)
topLayerView.alpha = 0.1
let singleTap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(singleTap))
singleTap.numberOfTapsRequired = 1
topLayerView.addGestureRecognizer(singleTap)
topLayerView.isUserInteractionEnabled = true
}
This is code that I have, and I can get the call to either buttonClicked function or singleTap function.
I looked over the web and found many similar questions, but nothing worked for me.
I have tried creating the new class that conforms to UIView protocol, and overrides 'point' function, but that didn't change a thing.
I don't think you can distribute a single touch to multiple views. However, I really don't think you need to.
You can subclass UIView and override hitTest to detect events and forward the events to the subviews you are interested in. If the event doesn't correspond to a subview, then you just return the superview so that the superview can process the event.
Here is what this method does:
Filters for subviews that are not itself and that are valid for touches by checking if the view is hidden, transparent, of if user interaction is disabled. Yes this is necessary in order to be compliant with the documentation: https://developer.apple.com/documentation/uikit/uiview/1622469-hittest
Propagate events to subviews of the superview.
Triggers an event if a subview has been touched.
Miscellaneous error checking
Note that this method will propagate events subviews that are nested inside other subviews. This works recursively.
The other thing I want to point out is how the subviews property is reversed. This is because the topmost subviews are stored at the end of the array, and those are the ones we want to process first.
class TrackerView: UIView {
var trackerAction: (TrackerEvent) -> Void = { _ in }
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
guard let superview = superview else {
return nil
}
lazy var superviewPoint = convert(point, to: superview)
let topMostViews = superview.subviews.reversed()
let subview = topMostViews.first(where: {
let subviewPoint = self.convert(point, to: $0)
let valid = $0.isUserInteractionEnabled && !$0.isHidden && $0.alpha >= 0.01
return valid && $0.point(inside: subviewPoint, with: event) && $0 !== self
})
guard let subview = subview else {
return processHit(for: superview, event: event, at: superviewPoint)
}
let subviewPoint = self.convert(point, to: subview)
guard let subviewHit = subview.hitTest(subviewPoint, with: event) else {
return processHit(for: superview, event: event, at: superviewPoint)
}
return processHit(for: subviewHit, event: event, at: superviewPoint)
}
private func processHit(for view: UIView?, event: UIEvent?, at point: CGPoint) -> UIView? {
guard let view = view, let event = event else { return view }
trackerAction(TrackerEvent(
viewType: type(of: view),
touchPoint: point,
timestamp: event.timestamp
))
return view
}
}
The event structure just stores some info that may be useful to you. Modify as needed. However, the reason why I include the timestamp is because hitTest is called more than once for a single event. The timestamp will allow you to weed out duplicates. It will also allow you to sort the events.
struct TrackerEvent: Hashable, Comparable, CustomStringConvertible {
let viewType: UIView.Type
let touchPoint: CGPoint
let timestamp: TimeInterval
func hash(into hasher: inout Hasher) {
hasher.combine(timestamp)
}
static func < (lhs: TrackerEvent, rhs: TrackerEvent) -> Bool {
lhs.timestamp < rhs.timestamp
}
static func == (lhs: TrackerEvent, rhs: TrackerEvent) -> Bool {
lhs.timestamp == rhs.timestamp
}
var description: String {
let elements = [
"viewType: \(viewType)",
"touchPoint: \(touchPoint)",
"timestamp: \(String(format: "%.02f", timestamp))",
]
let elementsJoined = elements.joined(separator: ", ")
return "[\(elementsJoined)]"
}
}
You may want a utility class to weed out duplicates every so often before processing them.
class TrackerEventHandler {
var events: Set<TrackerEvent> = []
private var timer: Timer?
func queueEvent(_ event: TrackerEvent) {
print("Queueing event", event)
events.insert(event)
}
func start() {
timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { [weak self] timer in
self?.events.sorted().forEach { event in
print("Handling event: \(event)")
}
self?.events.removeAll()
}
}
func stop() {
timer?.invalidate()
}
}
Usage is as follows:
class ViewController: UIViewController {
let handler = TrackerEventHandler()
override func viewDidLoad() {
super.viewDidLoad()
self.handler.start()
let topLayerView = TrackerView(frame: CGRect(x: 0, y: 0, width: 400, height: 900))
topLayerView.trackerAction = handler.queueEvent(_:)
self.view.addSubview(topLayerView)
// ...
}
// ...
}
Note that this is not a perfect implementation. There are limitations, but it might be a good starting point.
I am creating a PDF viewer for iPads, with which users can read a PDF by scrolling horizontally.
I created the following code to implement the single page view with page change with gestures (while consulting with How to create a single page vertical scrolling PDFView in Swift and elsewhere).
Although this approach works fine most of the time, I realized that gestures are not detected (or called) when a PDF file is zoomed in. Because of this, I cannot go to the next page by swiping the screen. Playing with the extension PDFView {} function I created, I found out that disabling the user interaction in subview enables me to detect the swipe gestures. However, now I cannot scroll the page inside the PDFView. I would appreciate it if you could help me figure out how to fix this.
What I would like to implement is something like PDF Expert (https://apps.apple.com/us/app/pdf-expert-pdf-reader-editor/id743974925), where I can scroll over to the next page horizontally.
Thank very much you for your help in advance!
import UIKit
import PDFKit
//PDF Zoom scale
var scaleOfPdf: CGFloat = 4
extension PDFView {
func disableBouncing(){
for subview in subviews{
if let scrollView = subview as? UIScrollView{
scrollView.bounces = false
return
}
}
class ViewController: UIViewController, UIGestureRecognizerDelegate, UIDocumentPickerDelegate {
#IBOutlet weak var pdfView: PDFView!
override func viewDidLoad(){
super.viewDidLoad()
pdfView.autoresizesSubviews = true
pdfView.autoresizingMask = [.flexibleWidth, .flexibleHeight, .flexibleTopMargin, .flexibleLeftMargin]
pdfView.displayDirection = .horizontal
pdfView.displayMode = .singlePage
pdfView.autoScales = true
// setting a color for background
pdfView.backgroundColor = .black
pdfView.document = pdfDocument
// pdfView.usePageViewController(true, withViewOptions: [UIPageViewController.OptionsKey.interPageSpacing: 20])
pdfView.maxScaleFactor = 4.0
pdfView.minScaleFactor = pdfView.scaleFactorForSizeToFit
pdfView.disableBouncing()
//setting swipe gesture
let leftSwipeGesture = UISwipeGestureRecognizer(target: self, action: #selector(respondLeftSwipeGesture(_:)))
leftSwipeGesture.direction = [UISwipeGestureRecognizer.Direction.left]
pdfView.addGestureRecognizer(leftSwipeGesture)
let rightSwipeGesture = UISwipeGestureRecognizer(target: self, action: #selector(respondRightSwipeGesture(_:)))
rightSwipeGesture.direction = [UISwipeGestureRecognizer.Direction.right]
pdfView.addGestureRecognizer(rightSwipeGesture)
}
//setting swipe-gesture
#objc func respondLeftSwipeGesture(_ sender: UISwipeGestureRecognizer) {
print("left swipe was detected")
if pdfView.document == nil { return }
scaleOfPdf = pdfView.scaleFactor
pdfView.goToNextPage(self)
pdfView.scaleFactor = scaleOfPdf
}
#objc func respondRightSwipeGesture(_ sender: UISwipeGestureRecognizer) {
print("right swipe was detected")
if pdfView.document == nil { return }
scaleOfPdf = pdfView.scaleFactor
pdfView.goToPreviousPage(self)
pdfView.scaleFactor = scaleOfPdf
}
}
Gesture Recognizers are working as a chain or pipeline that processes touches - after one (G1) fails, second one (G2) tries to recognize its gesture. Here you have at least 4 recognizers - your 2 ones (left and right), and the 2 scrollView's ones (pan and pinch). I will give the brief solution that covers only scrollView's pan recognizer, if you'll see problems also with pinch - you'll need to follow the same approach.
Let's say G1 is your left recognizer, and G2 is scrollView's pan recognizer.
In order to make G2 process the same touches as G1, they should be told to recognize simultaneously.
Also, the user might move his/her finger a bit horizontally while scrolling vertically, so in that case, you also want scrolling to start only after your G1 gives up on swipe and fails to recognize it.
In order to achieve that, you should add this code to your VC.
override func viewDidLoad(){
super.viewDidLoad()
...
leftSwipeGesture.delegate = self
leftSwipeGesture.cancelsTouchesInView = false
rightSwipeGesture.delegate = self
rightSwipeGesture.cancelsTouchesInView = false
}
optional func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return gestureRecognizer == leftSwipeGesture
|| gestureRecognizer == rightSwipeGesture
|| otherGestureRecognizer == leftSwipeGesture
|| otherGestureRecognizer == rightSwipeGesture
}
optional func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
guard let _ = gestureRecognizer as? UIPanGestureRecognizer else { return false }
return otherGestureRecognizer == leftSwipeGesture
|| otherGestureRecognizer == rightSwipeGesture
}
optional func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool {
guard let _ = otherGestureRecognizer as? UIPanGestureRecognizer else { return false }
return gestureRecognizer == leftSwipeGesture
|| gestureRecognizer == rightSwipeGesture
}
If UIGestureRecognizerDelegate methods that I added are not getting called, you'll need to create a subclass PDFView, make left/rightSwipeGesture.delegate = pdfView and override in your PDFView subclass its UIGestureRecognizerDelegate methods with this logic.
I have developed a UIView from For loop and basically it is create 3 Views from loop. and I have to add touch gesture on every View to call a method but I am unable to get current selected UIView.tag when I tap on it. it is only showing the .tag of the last view. here is my code.
for i in 0 ... 2 {
let productView = UIView()
productView.tag = i
productView.isUserInteractionEnabled = true
let producttap = UITapGestureRecognizer(target: self, action: #selector(self.ProductTapped))
productView.addGestureRecognizer(producttap)
productView.frame = CGRect(x: xOffset, y: CGFloat(buttonPadding), width: 200, height: scView1.frame.size.height)
xOffset = xOffset + CGFloat(buttonPadding) + productView.frame.size.width
scView1.addSubview(productView)
productIndex = productView.tag
}
and here is the method that I am calling from every UIView touch.
#objc func ProductTapped() {
print("",productIndex)
}
Your code should be using delegate/callback closure, but if you want to keep using tag, try change it to:
#objc func ProductTapped(_ sender: UITapGestureRecognizer) {
if let view = sender.view {
print(view.tag)
}
}
and the gesture attach to let producttap = UITapGestureRecognizer(target: self, action: #selector(self.ProductTapped(_:)))
productIndex does nothing here since it got overwritten on the loop
productIndex currently has no relationship to the tap gestures that you attach your views. You do set productIndex in the the loop but that's irrelevant to your gesture.
Perhaps you want
let producttap = UITapGestureRecognizer(target: self, action: #selector(productTapped(_:))
and
#objc func productTapped(_ gesture: UITapGestureRecognizer) {
print("tag is",gesture.view.tag)
}
I've been trying this for awhile. The code below is my UIPresentationController. When a button is pressed, I add a dimmed UIView and a second modal (presentedViewController) pops up halfway.
I added the tap gesture recognizer in the method presentationTransitionWillBegin()
I don't know why the tap gesture is not being registered when I click on the dimmed UIView.
I've tried changing the "target" and adding the gesture in a different place. Also looked at other posts, but nothing has worked for me.
Thanks
import UIKit
class PanModalPresentationController: UIPresentationController {
override var frameOfPresentedViewInContainerView: CGRect {
var frame: CGRect = .zero
frame.size = size(forChildContentContainer: presentedViewController, withParentContainerSize: containerView!.bounds.size)
frame.origin.y = containerView!.frame.height * (1.0 / 2.0)
print("frameOfPresentedViewInContainerView")
return frame
}
private lazy var dimView: UIView! = {
print("dimView")
guard let container = containerView else { return nil }
let dimmedView = UIView(frame: container.bounds)
dimmedView.backgroundColor = UIColor.black.withAlphaComponent(0.5)
dimmedView.isUserInteractionEnabled = true
return dimmedView
}()
override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController?) {
print("init presentation controller")
super.init(presentedViewController: presentedViewController, presenting: presentingViewController)
}
override func presentationTransitionWillBegin() {
guard let container = containerView else { return }
print("presentation transition will begin")
container.addSubview(dimView)
dimView.translatesAutoresizingMaskIntoConstraints = false
dimView.topAnchor.constraint(equalTo: container.topAnchor).isActive = true
dimView.leadingAnchor.constraint(equalTo: container.leadingAnchor).isActive = true
dimView.trailingAnchor.constraint(equalTo: container.trailingAnchor).isActive = true
dimView.bottomAnchor.constraint(equalTo: container.bottomAnchor).isActive = true
dimView.isUserInteractionEnabled = true
let recognizer = UITapGestureRecognizer(target: self, action: #selector(self.handleTap(_:)))
dimView.addGestureRecognizer(recognizer)
container.addSubview(presentedViewController.view)
presentedViewController.view.translatesAutoresizingMaskIntoConstraints = false
presentedViewController.view.bottomAnchor.constraint(equalTo: container.bottomAnchor).isActive = true
presentedViewController.view.widthAnchor.constraint(equalTo: container.widthAnchor).isActive = true
presentedViewController.view.heightAnchor.constraint(equalTo: container.heightAnchor).isActive = true
guard let coordinator = presentingViewController.transitionCoordinator else { return }
coordinator.animate(alongsideTransition: { _ in
self.dimView.alpha = 1.0
})
print(dimView.alpha)
}
override func dismissalTransitionWillBegin() {
guard let coordinator = presentedViewController.transitionCoordinator else {
print("dismissal coordinator")
self.dimView.alpha = 0.0
return
}
print("dismissal transition begin")
coordinator.animate(alongsideTransition: { _ in
self.dimView.alpha = 0.0
})
}
override func containerViewDidLayoutSubviews() {
print("containerViewDidLayoutSubviews")
presentedView?.frame = frameOfPresentedViewInContainerView
// presentedViewController.dismiss(animated: true, completion: nil)
}
override func size(forChildContentContainer container: UIContentContainer, withParentContainerSize parentSize: CGSize) -> CGSize {
print("size")
return CGSize(width: parentSize.width, height: parentSize.height * (1.0 / 2.0))
}
#objc func handleTap(_ sender: UITapGestureRecognizer) {
print("tapped")
// presentingViewController.dismiss(animated: true, completion: nil)
presentedViewController.dismiss(animated: true, completion: nil)
}
}
I can't tell what the frame/bounds of your presentedViewController.view is but even if it's top half has an alpha of 0 it could be covering your dimView and receiving the tap events instead of the dimView - since presentedViewController.view is added as a subview on top of dimView.
You may have to wait until after the controller is presented and add the gesture to its superview's first subview. I've used this before to dismiss a custom alert controller with a background tap. You could probably do something similar:
viewController.present(alertController, animated: true) {
// Enabling Interaction for Transparent Full Screen Overlay
alertController.view.superview?.subviews.first?.isUserInteractionEnabled = true
let tapGesture = UITapGestureRecognizer(target: alertController, action: #selector(alertController.dismissSelf))
alertController.view.superview?.subviews.first?.addGestureRecognizer(tapGesture)
}
Hmm, try using this instead. Let me know how it goes. It works for me.
class PC: UIPresentationController {
/*
We'll have a dimming view behind.
We want to be able to tap anywhere on the dimming view to do a dismissal.
*/
override var frameOfPresentedViewInContainerView: CGRect {
let f = super.frameOfPresentedViewInContainerView
var new = f
new.size.height /= 2
new.origin.y = f.midY
return new
}
override func presentationTransitionWillBegin() {
let con = self.containerView!
let v = UIView(frame: con.bounds)
v.backgroundColor = UIColor.black
v.alpha = 0
con.insertSubview(v, at: 0)
let tap = UITapGestureRecognizer(target: self, action: #selector(handleTap))
v.addGestureRecognizer(tap)
let tc = self.presentedViewController.transitionCoordinator!
tc.animate(alongsideTransition: { _ in
v.alpha = 1
}, completion: nil)
}
#objc func handleTap() {
print("tapped")
self.presentedViewController.dismiss(animated: true, completion: nil)
}
override func dismissalTransitionWillBegin() {
let con = self.containerView!
let v = con.subviews[0]
let tc = self.presentedViewController.transitionCoordinator!
tc.animate(alongsideTransition: { _ in
v.alpha = 0
}, completion: nil)
}
}
I took a look at your project just now. The problem is in your animation controller. If you comment out the functions in your transition delegate object that vend animation controllers, everything works fine.
But just looking at your animation controller, what you wanted to achieve was to have your new vc slide up / slide down. And in fact, you don't even need a custom animation controller for this; the modalTransitionStyle property of a view controller has a default value of coverVertical, which is just what you want I think.
In any case though, you can still use the presentation controller class I posted before, as it has same semantics from your class, just without unnecessary overrides.
Optional
Also just a tip if you'd like, you have these files right now in your project:
PanModalPresentationDelegate.swift
PanModalPresentationController.swift
PanModalPresentationAnimator.swift
TaskViewController.swift
HomeViewController.swift
What I normally do is abbreviate some of those long phrases, so that the name of the file and class conveys the essence of its nature without long un-needed boilerplate.
So HomeViewController and TaskViewController would be Home_VC and Task_VC. Those other 3 files are all for the presentation of one VC; it can get out of hand very quickly. So what I normally do there is call my presentation controller just PC and nest its declaration inside the VC class that will use it (in this case that's Task_VC). Until the time comes where it needs to be used by some other VC too; then it's more appropriate to put it in its own file and call it Something_PC but I've never actually needed to do that yet lol. And the same for any animation controllers ex. Fade_AC, Slide_AC etc. I tend to call transition delegate a TransitionManager and nest it in the presented VC's class. Makes it easier for me to think of it as just a thing that vends AC's / a PC.
Then your project simply becomes:
Home_VC.swift
Task_VC.swift
And if you go inside Task_VC, you'll see a nested TransitionManager and PC.
But yeah up to you 😃.
The dimmedView is behind presented view. You have a couple options to correct that.
First, is allow touches to pass through the top view, it must override pointInside:
- (BOOL) pointInside:(CGPoint)point withEvent:(UIEvent *)event {
for (UIView *subview in self.subviews) {
if ([subview hitTest:[self convertPoint:point toView:subview] withEvent:event]) {
return TRUE;
}
}
return FALSE;
}
Another options is to instead add the gesture recognizer to the presentedViewController.view, instead of the dimmedView. And, if you allow PanModalPresentationController to adopt the UIGestureRecognizerDelegate, and it as the delegate to the recognizer, you can determine if you should respond to touches, by implementing shouldReceive touch:
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
if (touch.view == presentedViewController.view) {
return true
}
return false
}
If you use the second option, don't forget to remove the gesture recognizer in dismissalTransitionWillBegin or dismissalTransitionDidEnd!
I am trying to create a custom UIView/Scrollview named MyScrollView that contains a few labels (UILabel), and these labels receive tap gestures/events in order to respond to user's selections .
In order to make the tap event work on the UILabels, I make sure they all have userIteractionEnabled = true and I created a delegate as below:
protocol MyScrollViewDelegate {
func labelClicked(recognizer: UITapGestureRecognizer)
}
The custom UIView is being used in ScrollViewController that I created, this ScrollViewController implements the delegate method as well:
import UIKit
import Neon
class ScrollViewController: UIViewController, MyScrollViewDelegate {
var curQuestion: IPQuestion?
var type: QuestionViewType?
var lastClickedLabelTag: Int = 0 //
init(type: QuestionViewType, question: IPQuestion) {
super.init(nibName: nil, bundle: nil)
self.curQuestion = question
self.type = type
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
self.automaticallyAdjustsScrollViewInsets = false
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func loadView() {
view = MyScrollView(delegate: self, q: curQuestion!)
view.userInteractionEnabled = true
}
}
// implementations for MyScrollViewDelegate
extension ScrollViewController {
func labelTitleArray() -> [String]? {
print("labelTitleArray called in implemented delegate")
return ["Comments", "Answers"]
}
func labelClicked(recognizer: UITapGestureRecognizer) {
print("labelClicked called in implemented delegate")
let controller = parentViewController as? ParentViewController
controller?.labelClicked(recognizer)
lastClickedLabelTag = recognizer.view!.tag
}
}
// MARK: - handle parent's ViewController event
extension QuestionDetailViewController {
func updateActiveLabelsColor(index: Int) {
print("updating active labels color: \(index)")
if let view = view as? MyScrollView {
for label in (view.titleScroll.subviews[0].subviews as? [UILabel])! {
if label.tag == index {
label.transform = CGAffineTransformMakeScale(1.1,1.1)
label.textColor = UIColor.purpleColor()
}
else {
label.transform = CGAffineTransformMakeScale(1,1)
label.textColor = UIColor.blackColor()
}
}
}
}
}
This above ScrollViewController is added, as a child view controller to the parent view controller, and positioned to the top part of the parent's view:
override func viewDidLoad() {
super.viewDidLoad()
self.automaticallyAdjustsScrollViewInsets = false
self.view.backgroundColor = UIColor.whiteColor()
addChildViewController(scrollViewController) // added as a child view controller here
view.addSubview(scrollViewController.view) // here .view is MyScrollView
scrollViewController.view.userInteractionEnabled = true
scrollViewController.view.anchorToEdge(.Top, padding: 0, width: view.frame.size.width, height: 100)
}
The app can load everything up in the view, but the tap gesture/events are not passed down to the labels in the custom MyScrollView. For this, I did some google search and have read Event Delivery: Responder Chain on Apple Developer website and did a hit test as well. The hitTest function below can be triggered in the MyScrollView:
override func hitTest(point: CGPoint, withEvent event: UIEvent?) -> UIView? {
print("hit test started, point: \(point), event: \(event)")
return self
}
My observations with the hitTest is that the touchesBegan() and touchesEnded() methods are triggered in the view only when the hitTest function is there. Without hitTest, both functions do not get called with taps.
but no luck getting the UILabel to respond to Tap Gestures. So I am reaching out to experts on SO here. Thanks for helping!
I think I found out the reason why the UILabel did not respond to tapping after much struggle: the .addGestureRecognizer() method to the label was run in the init() method of my custom UIView component, which is wrong, because the view/label may not have been rendered yet. Instead, I moved that code to the lifecycle method layoutSubviews(), and everything started to work well:
var lastLabel: UILabel? = nil
for i in 0..<scrollTitleArr.count {
let label = UILabel()
label.text = scrollTitleArr[i] ?? "nothing"
print("label: \(label.text)")
label.font = UIFont(name: "System", size: 15)
label.textColor = (i == 0) ? MaterialColor.grey.lighten2 : MaterialColor.grey.darken2
label.transform = (i == 0) ? CGAffineTransformMakeScale(1.1, 1.1) : CGAffineTransformMakeScale(0.9, 0.9)
label.sizeToFit()
label.tag = i // for tracking the label by tag number
label.userInteractionEnabled = true
label.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(self.labelClicked(_:))))
titleContainer.addSubview(label)
if lastLabel == nil {
label.anchorInCorner(.TopLeft, xPad: 0, yPad: 0, width: 85, height: 40)
// label.anchorToEdge(.Left, padding: 2, width: 85, height: 40)
} else {
label.align(.ToTheRightMatchingTop, relativeTo: lastLabel!, padding: labelHorizontalGap, width: 85, height: 40)
}
lastLabel = label
}
In addition, I don't need to implement any of the UIGestureRecognizer delegate methods and I don't need to make the container view or the scroll view userInteractionEnabled. More importantly, when embedding the custom UIView to a superview, I configured its size and set clipsToBounds = true.
I guess I should have read more UIView documentation on the Apple Developer website. Hope this will help someone like me in the future! Thanks to all!
You have to set the property userInteractionEnabled = YES.
For some reason, my simulator was frozen or something when the tap gesture recognizer wasn't working. So, when I restarted the app, then it all worked again. I don't know if this applies here, but that was the fix for me.