I had to create a new thread bcoz it's driving me crazy and all the other answers online are exactly the same. I have done this countless of times but I cannot see what I am missing for the life of me. I am using a "test" view controller just to get the tap gesture working but it isn't working at all... I am fairly certain that I am setting this up correctly, as this is how I've always implemented it in the past: (yes, I have checked the box for isUserInteractionEnabled). I am even implementing this on a different viewcontroller this exact way and it is working...
class TestViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.addGestureRecognizer(tap)
}
let tap = UITapGestureRecognizer(target: self, action: #selector(wasTapped))
#objc func wasTapped() {
print("tapped")
}
}
I have also tried adding the parameters to wasTapped:
#objc func wasTapped(gestureRecognizer: UITapGestureRecognizer) {
print("tapped")
}
You are saying:
override func viewDidLoad() {
super.viewDidLoad()
view.addGestureRecognizer(tap)
}
let tap = UITapGestureRecognizer(target: self, action: #selector(wasTapped))
The problem is the last line:
let tap = UITapGestureRecognizer(target: self, action: #selector(wasTapped))
You cannot just say let tap like that in the middle of nowhere. You are implicitly making an instance property. But you cannot initialize an instance property with a target of self, because self does not exist at the time an instance property is initialized. (I regard the fact that that code even compiles as a bug, and have reported it as such.)
Move that line to the start of viewDidLoad, like this:
override func viewDidLoad() {
super.viewDidLoad()
let tap = UITapGestureRecognizer(target: self, action: #selector(wasTapped))
view.addGestureRecognizer(tap)
}
Try something like this
override func viewDidLoad() {
super.viewDidLoad()
let tap = UITapGestureRecognizer(target: self, action: #selector(wasTapped(sender:)))
tap.numberOfTapsRequired = 1 // Default value
view.isUserInteractionEnabled = true
view.addGestureRecognizer(tap)
}
#objc func wasTapped(sender: UITapGestureRecognizer) {
print("tapped")
}
You have to enable interaction if you want to use gesture recognizers for standard UIView's
Add view.isUserInteractionEnabled = true in your viewDidLoad.
var tapGesture = UITapGestureRecognizer()
take a view and set IBOutlet like:
#IBOutlet weak var viewTap: UIView!
Write pretty code on viewDidLoad() like:
tapGesture = UITapGestureRecognizer(target: self, action: #selector(self.myviewTapped(_:)))
tapGesture.numberOfTapsRequired = 1
tapGesture.numberOfTouchesRequired = 1
viewTap.addGestureRecognizer(tapGesture)
viewTap.isUserInteractionEnabled = true
this method is calling when tap gesture recognized:
#objc func myviewTapped(_ sender: UITapGestureRecognizer) {
if self.viewTap.backgroundColor == UIColor.yellow {
self.viewTap.backgroundColor = UIColor.green
}else{
self.viewTap.backgroundColor = UIColor.yellow
}
}
Related
I have a collection of views and I want to make that when they are tapped, it will perform the same segue. and no view performs any segue.
class ViewController: UIViewController {
#IBOutlet var categoryViews: [UIView]!
let tapGesture = UIGestureRecognizer(target: self, action: #selector(ViewController.move(tap:)))
override func viewDidLoad() {
super.viewDidLoad()
for category in (0..<categoryViews.count) {
categoryViews[category].addGestureRecognizer(tapGesture)
categoryViews[category].isUserInteractionEnabled = true
}
// Do any additional setup after loading the view.
}
#objc func move(tap: UIGestureRecognizer) {
performSegue(withIdentifier: "Animals", sender: nil)
}
}
A single instance of UITapGestureRecognizer can be added to a single view.
In your code, since you're using a single instance of UITapGestureRecognizer for each view, the tapGesture will be added only to the last view in categoryViews array.
You need to create different UITapGestureRecognizer instance for each view in categoryViews, i.e.
class ViewController: UIViewController {
#IBOutlet var categoryViews: [UIView]!
override func viewDidLoad() {
super.viewDidLoad()
categoryViews.forEach {
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(move(tap:)))
$0.addGestureRecognizer(tapGesture)
$0.isUserInteractionEnabled = true
}
}
#objc func move(tap: UITapGestureRecognizer) {
performSegue(withIdentifier: "Animals", sender: nil)
}
}
The problem is that this code doesn't do what you think it does:
class ViewController: UIViewController {
let tapGesture = UIGestureRecognizer(target: self, action: #selector(ViewController.move(tap:)))
Your let tapGesture is an instance property declaration, and what follows the equal sign is its initializer. But you can't speak of self in an instance property initializer; there is no instance yet. So self here is taken to be the class. Thus, your tap gesture recognizer "works", but the move message is not sent to your ViewController instance; in effect, it is sent into empty space.
To fix this, you can initialize tapGesture at a time when self does exist. For example:
class ViewController: UIViewController {
let tapGesture : UIGestureRecognizer!
func viewDidLoad() {
self.tapGesture = UITapGestureRecognizer(target: self, action: #selector(ViewController.move(tap:)))
I have a bar button in the right side of the screen, it's barButtonSystemItem: .edit and it's used to put tableView in the editing mode. I want when, user tap on it, it change to barButtonSystemItem: .done and it close tableview from editing mode.
Just to be clear, every time that barButton is clicked, the type of it should be change from edit to done.
Here is my code, but it always stay with edit, and not changing to done
fileprivate func addBarButton() {
if tableView.isEditing {
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(editButtonAction))
} else {
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .edit, target: self, action: #selector(doneButtonAction))
}
}
#objc func editButtonAction(sender: UIBarButtonItem) {
tableView.isEditing = !tableView.isEditing
}
#objc func doneButtonAction(sender: UIBarButtonItem) {
tableView.isEditing = !tableView.isEditing
}
override func viewDidLoad() {
super.viewDidLoad()
addBarButton()
tableView?.isEditing = true
}
In the bodies of methods editButtonAction and editButtonAction you only change the tableView editing state by doing tableView.isEditing = !tableView.isEditing. This action does nothing to navigationItem at all.
I'd recommend you to refactor the code a bit by renaming addBarButton into updateBarButton and call it every time when the table editing state changes and additionally from viewDidLoad as you do now. So your code would become something like this:
fileprivate func updateBarButton() {
if tableView.isEditing {
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(editButtonAction))
} else {
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .edit, target: self, action: #selector(doneButtonAction))
}
}
#objc func editButtonAction(sender: UIBarButtonItem) {
tableView.isEditing = !tableView.isEditing
updateBarButton() // Note the additional call of the update method
}
#objc func doneButtonAction(sender: UIBarButtonItem) {
tableView.isEditing = !tableView.isEditing
updateBarButton() // Note the additional call of the update method
}
override func viewDidLoad() {
super.viewDidLoad()
tableView?.isEditing = true
updateBarButton() // Note that we call this method after changing the table view state so that it will have the most recent value
}
I would like to block interactions with users, with the exception of the double tap for cancel.
Is it possible to put isUserInteractionEnabled = false and an exception rule for my double tap lines below ?
override func viewDidLoad() {
super.viewDidLoad()
let tapGR = UITapGestureRecognizer(target: self, action: #selector(PostlistViewController.handleTap(_:)))
tapGR.delegate = self
tapGR.numberOfTapsRequired = 2
view.addGestureRecognizer(tapGR)
}
--
extension MainBoardController: UIGestureRecognizerDelegate {
func handleTap(_ gesture: UITapGestureRecognizer){
print("doubletapped")
}
}
Thanks!
So when ever I long press on a button, it recognizes the long press, but "test" gets called twice. How do I prevent that from happening?
#IBOutlet weak var button2: UIButton!
func longPressMe(){
print("test")
}
func longPressGes(){
let longpress = UILongPressGestureRecognizer(target: self, action: "longPressMe")
longpress.minimumPressDuration = 1
button2.addGestureRecognizer(longpress)
}
override func viewDidLoad() {
super.viewDidLoad()
longPressGes()
}
You have to check the state of the gesture recognizer. Change longPressMe() to something like this:
func longPressMe(recognizer: UILongPressGestureRecognizer) {
guard recognizer.state == .Began else { return }
// do stuff here
}
Have a try, here is how to use #selector:
func longPressMe(recognizer: UILongPressGestureRecognizer) {
// do stuff here
}
func longPressGes(){
let longpress = UILongPressGestureRecognizer(target: self, action: #selector(yourViewController.longPressMe(_:)))
longpress.minimumPressDuration = 1
button2.addGestureRecognizer(longpress)
}
I want use a custom touch event in a view. There is a web view which is the subview of this view.
I override touchBegan and other functions but it does not run.
If you want to call a function while tapping a view you can use UITapGestureRecognizer
override func viewDidLoad() {
super.viewDidLoad()
let tapRecognizer = UITapGestureRecognizer(target: view, action: "handleSingleTap:")
tapRecognizer.numberOfTapsRequired = 1
self.view.addGestureRecognizer(tapRecognizer)
}
func handleSingleTap(recognizer: UITapGestureRecognizer) {
//Do something here with the gesture
}
For Swift 3:
override func viewDidLoad() {
super.viewDidLoad()
let tapRecognizer = UITapGestureRecognizer(target: view, action: #selector(handleSingleTap))
tapRecognizer.numberOfTapsRequired = 1
self.view.addGestureRecognizer(tapRecognizer)
}
#objc func handleSingleTap(recognizer: UITapGestureRecognizer) {
//Do something here with the gesture
}