How to detect longpress in BarButtonitem - ios

I have a UIBarButtonItem in navigation bar. When a user clicks it, it pops to another viewController.
Now i want that when user long-press on that button (navigation bar button) I want to show a help message.
I want help to detect the onlick event and longpress event separately.

You should create a button and set UITapGestureRecognizer & UILongPressGestureRecognizer to your button
// Create a button
let yourButton = UIButton()
yourButton.backgroundColor = .red
yourButton.setTitle("long press", for: .normal)
// Create a tap gesture recognizer
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(didTap))
// Create a long gesture recognizer
let longGesture = UILongPressGestureRecognizer(target: self, action: #selector(long))
// You can set minimum duration of the press action
longGesture.minimumPressDuration = 3 //The default duration is 0.5 seconds.
// Add your gestures to button
yourButton.addGestureRecognizer(longGesture)
yourButton.addGestureRecognizer(tapGesture)
navigationItem.leftBarButtonItem = UIBarButtonItem(customView: yourButton)
#objc private func didTap() {
print("Did Tap")
}
#objc private func long() {
// You can show the help message in here
print("Long press")
}

try this in view didload:
let back = UIImage(named: "header_backarrow")
let backView = UIImageView(image: back)
backView.isUserInteractionEnabled = true
let tap = UITapGestureRecognizer(target: self, action: #selector(dismissManual))
backView.addGestureRecognizer(tap)
let backItem = UIBarButtonItem(customView: backView)
navigationItem.leftBarButtonItem = backItem

In the viewDidAppear of your view controller you can add this :
let gestureRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(myCalledFunction))
(myUIBarButton.value(forKey: "view") as? UIView)?.addGestureRecognizer(gestureRecognizer)
This is difficult because UIBarButton doesn't really expose its view and so you cannot directly add a gestureRecognizer to it.
You can however get a reference to its view by using the value(forKey:) method and then play with it.
Do not do this in the viewDidLoad as it is necessary for the view to have already been created in order for this to work.

All of the other answers require implementing a UIBarButtonItem(customView:) to achieve this. However this can be implemented with any UIBarButtonItem instance without implementing your own gesture recognizer code.
An #IBAction can actually be passed a second parameter containing the UIEvent triggering the action. For example, instead of defining -
#objc func doSomething(sender: UIBarButtonItem) {
}
We can define -
#objc func doSomething(sender: UIBarButtonItem, forEvent event: UIEvent) {
guard let touch = event.allTouches?.first else { return }
if touch.tapCount == 1 {
// Handle tap
} else if touch.tapCount == 0 {
// Handle long press
}
}
Source : http://li366-68.members.linode.com/2016/09/07/detecting-long-presses-on-uibarbuttonitems.html

so I found that UIBarButton has not property like longpress so all I do is take a UIButton give it longpress gesture and add that UIButton in navigation bar as UIBarButtonItem.
I hope it will helpful for someone else who is facing same problem.
let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
btn.backgroundColor = .green
let gesture = UILongPressGestureRecognizer(target: self, action: #selector(longpress))
btn.addGestureRecognizer(gesture)
let barbtn = UIBarButtonItem(customView: btn)
self.navigationItem.rightBarButtonItem = barbtn
thank you :)

Related

Getting UiView tag when touched

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)
}

Action not being triggered for UIBarButtonItem

first post so apologies if I mess something up. I have researched this for hours upon hours and read other posts here on stack exchange to no avail.
I have created a nib file that defines a custom view and have defined a custom class (UIView) to manage the outlets of the custom view. As you can see from the code below excerpted from my custom UIView class associated with the nib, I have a date picker as the input view for the custom class and a UIToolBar with two UIBarButtonItems. Both of these appear as desired through a tap gesture recognizer... however the problem is the UIBarButtonItems do not call the action when tapped. Placing a breakpoint in the action function reveals that the code is never run. I feel that something with the view lifecycle is preventing a reference from being made, but I am new to Swift so some help here would be appreciated. I don't think it is selector syntax as the tap gesture recognizer works as desired. I've tried messing with button click handling access levels. I've tried doing input view setup when the view awakes from the nib as well, along with trying to put the code in different parts of the lifecycle.
If it matters for lifecycle's sake, this nib is a part of a table view cell. I call for this nib to be loaded when the table view cell awakes from it's nib.
Thanks!
#IBOutlet weak var timerStackView: UIStackView!{
didSet{
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(HandleTap(_:)))
timerStackView.addGestureRecognizer(tapGesture)
}
}
var datePicker: UIDatePicker {
let picker = UIDatePicker()
picker.backgroundColor = UIColor.black
picker.isOpaque = false
picker.setValue(UIColor.white, forKey: "textColor")
return picker
}
var datePickerAccessoryView: UIToolbar {
let accessoryView = UIToolbar()
let doneButton = UIBarButtonItem(title: "Done", style: UIBarButtonItemStyle.done, target: self, action: #selector(handleDatePickerButtonClick(_:)))
doneButton.tintColor = UIColor.white
let cancelButton = UIBarButtonItem(title: "Cancel", style: UIBarButtonItemStyle.plain, target: self, action: #selector(handleDatePickerButtonClick(_:)))
cancelButton.tintColor = UIColor.white
accessoryView.setItems([cancelButton, doneButton], animated: true)
return accessoryView
}
override var inputView: UIView? {return datePicker}
override var inputAccessoryView: UIView? {return datePickerAccessoryView}
override var canBecomeFirstResponder: Bool {return true}
override var canResignFirstResponder: Bool {return true}
// MARK: - Private functions
#objc fileprivate func HandleTap(_ sender: UITapGestureRecognizer) -> Void {
if !self.isFirstResponder {
switch sender.state {
case .ended:
datePicker.date = Date()
self.becomeFirstResponder()
default:
break
}
}
}
#objc #IBAction internal func handleDatePickerButtonClick(_ sender: UIBarButtonItem) -> Void {
switch sender.title! {
case "Done":
// To be implemented
case "Cancel":
// To be implemented
default:
break
}
}
You are initialising the UIToolbar without a frame and that would make it not register any touch events because they would be out of the toolbar's bounds.
Replace let accessoryView = UIToolbar() with something like let accessoryView = UIToolbar(frame: CGRect(x: 0, y: 0, width: view.bounds.width, height: 44))
Or you can call accessoryView.sizeToFit() before return accessoryView
I suppose the tap gesture recognizer is interfering with native UIBarButtonItem click events. But why do you use a gesture recognizer for that?
You should better add an action to each particular UIBarButtonItem.

UIImageview click not working

I am very new to swift. I am implementing the functionality for click event for UIIMageview. My Code is below.
override func viewDidLoad() {
super.viewDidLoad()
initialize()
let logout = UIImage(named: "logout.png")
let location = UIImage(named:"location.png")
let appIcon = UIImage(named: "logo.png")
imgLogout.image = logout
imgLocation.image = location
appicon.image = appIcon
// Do any additional setup after loading the view, typically from a nib.
imgLogout.isUserInteractionEnabled = true
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(ProductListController.profileImageHasBeenTapped(gesture:)))
//this is where we add the target, since our method to track the taps is in this class
//we can just type "self", and then put our method name in quotes for the action parameter
//finally, this is where we add the gesture recognizer, so it actually functions correctly
imgLogout.addGestureRecognizer(tapGestureRecognizer)
}
func profileImageHasBeenTapped(gesture: UIGestureRecognizer){
print("Triggered")
}
my click event is not triggered. Any body can help me from this.
Any will be appreciated.
XCode version is 8.3.3
Swift version is 3.1
Why not using a UIButton, that is designed for that kind of usage ?
let logout = UIButton(type: .custom)
logout.setImage(UIImage(named: "logout.png"), forState: .normal)
logout.addTarget(self, action: #selector(self.performLogout), for: .touchUpInside)
#objc
func performLogout() {
// Do something
}
It seems like yourchildview not in the front so try it:
yourparentview.bringSubview(toFront: imgLogout)
imageLogOut frame may be out of super view's bounds, please check it.use
self.profileImageHasBeenTapped(gesture:)
instead of
ProductListController.profileImageHasBeenTapped(gesture:)
set user interaction enabled for the image.
// for creating tap gesture recognizer
#IBOutlet weak var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// create tap gesture recognizer
let tapGesture = UITapGestureRecognizer(target: self, action: "imageTapped:")
// add it to the image view;
imageView.addGestureRecognizer(tapGesture)
// make sure imageView can be interacted with by user
imageView.userInteractionEnabled = true
//if tap is not working bring image to front view
self.view.bringSubview(imageView)
}
func imageTapped(gesture: UIGestureRecognizer) {
// if the tapped view is a UIImageView then set it to imageview
if let imageView = gesture.view as? UIImageView {
println("Image Tapped")
//Here you can initiate your new ViewController
}
}
}

Single tap, created by UITapGestureRecognizer, doesn't work on UIButton

I have a lot of UIButtons without any acion. I want call some action in tap handler function. I create single tap with UITapGestureRecognizer. When I tap not on my UIButton, single tap handler work. When I tap on my UIButton, I see animation of pressing this button, but single tap handler doesn't work. Also I create double tap, and it works fine.
Question №1
What I can do with single tap? Handler should work, when I tap on my UIButton.
Question №2
How I can get UIButton in tap handler? I need get text label from this button.
Part of my code:
override func viewDidLoad() {
...
let singleTap = UITapGestureRecognizer(target: self, action: "singleTap:")
singleTap.numberOfTapsRequired = 1
singleTap.numberOfTouchesRequired = 1
view.addGestureRecognizer(singleTap)
let doubleTap = UITapGestureRecognizer(target: self, action: "doubleTap:")
doubleTap.numberOfTapsRequired = 2
doubleTap.numberOfTouchesRequired = 1
view.addGestureRecognizer(doubleTap)
singleTap.requireGestureRecognizerToFail(doubleTap)
...
}
func doubleTap(sender: UIGestureRecognizer) {
if sender.state == .Ended {
print("doubleTap")
}
}
func singleTap(sender: UIGestureRecognizer) {
if sender.state == .Ended {
print("singleTap")
}
}
func addButton(time:String, x:CGFloat, y:CGFloat, width:CGFloat, height:CGFloat, tag: Int) -> UIButton {
let button = UIButton(type: UIButtonType.System) as UIButton
button.frame = CGRectMake(x, y, width, height)
button.setTitle(time, forState: UIControlState.Normal)
button.tag = tag
self.scrollView.addSubview(button)
return button
}
If you want to add TapGesture into Button then do it like this way:
let singleTap = UITapGestureRecognizer(target: self, action: "singleTap:")
singleTap.numberOfTapsRequired = 1
singleTap.numberOfTouchesRequired = 1
yourButton.addGestureRecognizer(singleTap)

How to add a touch event to a UIView?

How do I add a touch event to a UIView?
I try:
UIView *headerView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, tableView.bounds.size.width, nextY)] autorelease];
[headerView addTarget:self action:#selector(myEvent:) forControlEvents:UIControlEventTouchDown];
// ERROR MESSAGE: UIView may not respond to '-addTarget:action:forControlEvents:'
I don't want to create a subclass and overwrite
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
In iOS 3.2 and higher, you can use gesture recognizers. For example, this is how you would handle a tap event:
//The setup code (in viewDidLoad in your view controller)
UITapGestureRecognizer *singleFingerTap =
[[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(handleSingleTap:)];
[self.view addGestureRecognizer:singleFingerTap];
//The event handling method
- (void)handleSingleTap:(UITapGestureRecognizer *)recognizer
{
CGPoint location = [recognizer locationInView:[recognizer.view superview]];
//Do stuff here...
}
There are a bunch of built in gestures as well. Check out the docs for iOS event handling and UIGestureRecognizer. I also have a bunch of sample code up on github that might help.
Gesture Recognizers
There are a number of commonly used touch events (or gestures) that you can be notified of when you add a Gesture Recognizer to your view. They following gesture types are supported by default:
UITapGestureRecognizer Tap (touching the screen briefly one or more times)
UILongPressGestureRecognizer Long touch (touching the screen for a long time)
UIPanGestureRecognizer Pan (moving your finger across the screen)
UISwipeGestureRecognizer Swipe (moving finger quickly)
UIPinchGestureRecognizer Pinch (moving two fingers together or apart - usually to zoom)
UIRotationGestureRecognizer Rotate (moving two fingers in a circular direction)
In addition to these, you can also make your own custom gesture recognizer.
Adding a Gesture in the Interface Builder
Drag a gesture recognizer from the object library onto your view.
Control drag from the gesture in the Document Outline to your View Controller code in order to make an Outlet and an Action.
This should be set by default, but also make sure that User Action Enabled is set to true for your view.
Adding a Gesture Programmatically
To add a gesture programmatically, you (1) create a gesture recognizer, (2) add it to a view, and (3) make a method that is called when the gesture is recognized.
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var myView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// 1. create a gesture recognizer (tap gesture)
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(sender:)))
// 2. add the gesture recognizer to a view
myView.addGestureRecognizer(tapGesture)
}
// 3. this method is called when a tap is recognized
#objc func handleTap(sender: UITapGestureRecognizer) {
print("tap")
}
}
Notes
The sender parameter is optional. If you don't need a reference to the gesture then you can leave it out. If you do so, though, remove the (sender:) after the action method name.
The naming of the handleTap method was arbitrary. Name it whatever you want using action: #selector(someMethodName(sender:)).
More Examples
You can study the gesture recognizers that I added to these views to see how they work.
Here is the code for that project:
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var tapView: UIView!
#IBOutlet weak var doubleTapView: UIView!
#IBOutlet weak var longPressView: UIView!
#IBOutlet weak var panView: UIView!
#IBOutlet weak var swipeView: UIView!
#IBOutlet weak var pinchView: UIView!
#IBOutlet weak var rotateView: UIView!
#IBOutlet weak var label: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Tap
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap))
tapView.addGestureRecognizer(tapGesture)
// Double Tap
let doubleTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTap))
doubleTapGesture.numberOfTapsRequired = 2
doubleTapView.addGestureRecognizer(doubleTapGesture)
// Long Press
let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPress(gesture:)))
longPressView.addGestureRecognizer(longPressGesture)
// Pan
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePan(gesture:)))
panView.addGestureRecognizer(panGesture)
// Swipe (right and left)
let swipeRightGesture = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipe(gesture:)))
let swipeLeftGesture = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipe(gesture:)))
swipeRightGesture.direction = UISwipeGestureRecognizerDirection.right
swipeLeftGesture.direction = UISwipeGestureRecognizerDirection.left
swipeView.addGestureRecognizer(swipeRightGesture)
swipeView.addGestureRecognizer(swipeLeftGesture)
// Pinch
let pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(handlePinch(gesture:)))
pinchView.addGestureRecognizer(pinchGesture)
// Rotate
let rotateGesture = UIRotationGestureRecognizer(target: self, action: #selector(handleRotate(gesture:)))
rotateView.addGestureRecognizer(rotateGesture)
}
// Tap action
#objc func handleTap() {
label.text = "Tap recognized"
// example task: change background color
if tapView.backgroundColor == UIColor.blue {
tapView.backgroundColor = UIColor.red
} else {
tapView.backgroundColor = UIColor.blue
}
}
// Double tap action
#objc func handleDoubleTap() {
label.text = "Double tap recognized"
// example task: change background color
if doubleTapView.backgroundColor == UIColor.yellow {
doubleTapView.backgroundColor = UIColor.green
} else {
doubleTapView.backgroundColor = UIColor.yellow
}
}
// Long press action
#objc func handleLongPress(gesture: UILongPressGestureRecognizer) {
label.text = "Long press recognized"
// example task: show an alert
if gesture.state == UIGestureRecognizerState.began {
let alert = UIAlertController(title: "Long Press", message: "Can I help you?", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
}
// Pan action
#objc func handlePan(gesture: UIPanGestureRecognizer) {
label.text = "Pan recognized"
// example task: drag view
let location = gesture.location(in: view) // root view
panView.center = location
}
// Swipe action
#objc func handleSwipe(gesture: UISwipeGestureRecognizer) {
label.text = "Swipe recognized"
// example task: animate view off screen
let originalLocation = swipeView.center
if gesture.direction == UISwipeGestureRecognizerDirection.right {
UIView.animate(withDuration: 0.5, animations: {
self.swipeView.center.x += self.view.bounds.width
}, completion: { (value: Bool) in
self.swipeView.center = originalLocation
})
} else if gesture.direction == UISwipeGestureRecognizerDirection.left {
UIView.animate(withDuration: 0.5, animations: {
self.swipeView.center.x -= self.view.bounds.width
}, completion: { (value: Bool) in
self.swipeView.center = originalLocation
})
}
}
// Pinch action
#objc func handlePinch(gesture: UIPinchGestureRecognizer) {
label.text = "Pinch recognized"
if gesture.state == UIGestureRecognizerState.changed {
let transform = CGAffineTransform(scaleX: gesture.scale, y: gesture.scale)
pinchView.transform = transform
}
}
// Rotate action
#objc func handleRotate(gesture: UIRotationGestureRecognizer) {
label.text = "Rotate recognized"
if gesture.state == UIGestureRecognizerState.changed {
let transform = CGAffineTransform(rotationAngle: gesture.rotation)
rotateView.transform = transform
}
}
}
Notes
You can add multiple gesture recognizers to a single view. For the sake of simplicity, though, I didn't do that (except for the swipe gesture). If you need to for your project, you should read the gesture recognizer documentation. It is fairly understandable and helpful.
Known issues with my examples above: (1) Pan view resets its frame on next gesture event. (2) Swipe view comes from the wrong direction on the first swipe. (These bugs in my examples should not affect your understanding of how Gestures Recognizers work, though.)
I think you can simply use
UIControl *headerView = ...
[headerView addTarget:self action:#selector(myEvent:) forControlEvents:UIControlEventTouchDown];
i mean headerView extends from UIControl.
Swift 3 & Swift 4
import UIKit
extension UIView {
func addTapGesture(tapNumber: Int, target: Any, action: Selector) {
let tap = UITapGestureRecognizer(target: target, action: action)
tap.numberOfTapsRequired = tapNumber
addGestureRecognizer(tap)
isUserInteractionEnabled = true
}
}
Use
yourView.addTapGesture(tapNumber: 1, target: self, action: #selector(yourMethod))
Based on the accepted answer you can define a macro:
#define handle_tap(view, delegate, selector) do {\
view.userInteractionEnabled = YES;\
[view addGestureRecognizer: [[UITapGestureRecognizer alloc] initWithTarget:delegate action:selector]];\
} while(0)
This macro uses ARC, so there's no release call.
Macro usage example:
handle_tap(userpic, self, #selector(onTapUserpic:));
In Swift 4.2 and Xcode 10
Use UITapGestureRecognizer for to add touch event
//Add tap gesture to your view
let tap = UITapGestureRecognizer(target: self, action: #selector(handleGesture))
yourView.addGestureRecognizer(tap)
// GestureRecognizer
#objc func handleGesture(gesture: UITapGestureRecognizer) -> Void {
//Write your code here
}
If you want to use SharedClass
//This is my shared class
import UIKit
class SharedClass: NSObject {
static let sharedInstance = SharedClass()
//Tap gesture function
func addTapGesture(view: UIView, target: Any, action: Selector) {
let tap = UITapGestureRecognizer(target: target, action: action)
view.addGestureRecognizer(tap)
}
}
I have 3 views in my ViewController called view1, view2 and view3.
override func viewDidLoad() {
super.viewDidLoad()
//Add gestures to your views
SharedClass.sharedInstance.addTapGesture(view: view1, target: self, action: #selector(handleGesture))
SharedClass.sharedInstance.addTapGesture(view: view2, target: self, action: #selector(handleGesture))
SharedClass.sharedInstance.addTapGesture(view: view3, target: self, action: #selector(handleGesture2))
}
// GestureRecognizer
#objc func handleGesture(gesture: UITapGestureRecognizer) -> Void {
print("printed 1&2...")
}
// GestureRecognizer
#objc func handleGesture2(gesture: UITapGestureRecognizer) -> Void {
print("printed3...")
}
You can achieve this by adding Gesture Recogniser in your code.
Step 1: ViewController.m:
// Declare the Gesture.
UITapGestureRecognizer *gesRecognizer = [[UITapGestureRecognizer alloc]
initWithTarget:self
action:#selector(handleTap:)];
gesRecognizer.delegate = self;
// Add Gesture to your view.
[yourView addGestureRecognizer:gesRecognizer];
Step 2: ViewController.m:
// Declare the Gesture Recogniser handler method.
- (void)handleTap:(UITapGestureRecognizer *)gestureRecognizer{
NSLog(#"Tapped");
}
NOTE: here yourView in my case was #property (strong, nonatomic) IBOutlet UIView *localView;
EDIT: *localView is the white box in Main.storyboard from below
Heres a Swift version:
// MARK: Gesture Extensions
extension UIView {
func addTapGesture(#tapNumber: Int, target: AnyObject, action: Selector) {
let tap = UITapGestureRecognizer (target: target, action: action)
tap.numberOfTapsRequired = tapNumber
addGestureRecognizer(tap)
userInteractionEnabled = true
}
func addTapGesture(#tapNumber: Int, action: ((UITapGestureRecognizer)->())?) {
let tap = BlockTap (tapCount: tapNumber, fingerCount: 1, action: action)
addGestureRecognizer(tap)
userInteractionEnabled = true
}
}
Swift 3:
let tapGestureRecognizer: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleTapGestureRecognizer(_:)))
view.addGestureRecognizer(tapGestureRecognizer)
func handleTapGestureRecognizer(_ gestureRecognizer: UITapGestureRecognizer) {
}
Objective-C:
UIControl *headerView = [[UIControl alloc] initWithFrame:CGRectMake(0, 0, tableView.bounds.size.width, nextY)];
[headerView addTarget:self action:#selector(myEvent:) forControlEvents:UIControlEventTouchDown];
Swift:
let headerView = UIControl(frame: CGRect(x: 0, y: 0, width: tableView.bounds.size.width, height: nextY))
headerView.addTarget(self, action: #selector(myEvent(_:)), for: .touchDown)
The question asks:
How do I add a touch event to a UIView?
It isn't asking for a tap event.
Specifically OP wants to implement UIControlEventTouchDown
Switching the UIView to UIControl is the right answer here because Gesture Recognisers don't know anything about .touchDown, .touchUpInside, .touchUpOutside etc.
Additionally, UIControl inherits from UIView so you're not losing any functionality.
If all you want is a tap, then you can use the Gesture Recogniser. But if you want finer control, like this question asks for, you'll need UIControl.
https://developer.apple.com/documentation/uikit/uicontrol?language=objc
https://developer.apple.com/documentation/uikit/uigesturerecognizer?language=objc
Swift 5.3
Solution with Closure, based on: UIGestureRecognizer with closure
final class BindableGestureRecognizer: UITapGestureRecognizer {
private var action: () -> Void
init(action: #escaping () -> Void) {
self.action = action
super.init(target: nil, action: nil)
self.addTarget(self, action: #selector(execute))
}
#objc private func execute() {
action()
}
}
public extension UIView {
/// A discrete gesture recognizer that interprets single or multiple taps.
/// - Parameters:
/// - tapNumber: The number of taps necessary for gesture recognition.
/// - closure: A selector that identifies the method implemented by the target to handle the gesture recognized by the receiver. The action selector must conform to the signature described in the class overview. NULL is not a valid value.
func addTapGesture(tapNumber: Int = 1, _ closure: (() -> Void)?) {
guard let closure = closure else { return }
let tap = BindableGestureRecognizer(action: closure)
tap.numberOfTapsRequired = tapNumber
addGestureRecognizer(tap)
isUserInteractionEnabled = true
}
}
Using:
view.addTapGesture { [weak self] in
self?.view.backgroundColor = .red
}
Simple and Useful Extension:
extension UIView {
private struct OnClickHolder {
static var _closure:()->() = {}
}
private var onClickClosure: () -> () {
get { return OnClickHolder._closure }
set { OnClickHolder._closure = newValue }
}
func onTap(closure: #escaping ()->()) {
self.onClickClosure = closure
isUserInteractionEnabled = true
let tap = UITapGestureRecognizer(target: self, action: #selector(onClickAction))
addGestureRecognizer(tap)
}
#objc private func onClickAction() {
onClickClosure()
}
}
Usage:
override func viewDidLoad() {
super.viewDidLoad()
let view = UIView(frame: .init(x: 0, y: 0, width: 80, height: 50))
view.backgroundColor = .red
view.onTap {
print("View Tapped")
}
}
Here is ios tapgesture;
First you need to create action for GestureRecognizer after write the below code under the action as shown below
- (IBAction)tapgesture:(id)sender
{
[_password resignFirstResponder];
[_username resignFirstResponder];
NSLog(#" TapGestureRecognizer tapped");
}
Another way is adding a transparent button to the view
UIButton *b = [UIButton buttonWithType:UIButtonTypeCustom];
b.frame = CGRectMake(0, 0, headerView.width, headerView.height);
[headerView addSubview:b];
[b addTarget:self action:#selector(buttonClicked:) forControlEvents:UIControlEventTouchDown];
And then, handle click:
- (void)buttonClicked:(id)sender
{}
Create a gesture recognizer (subclass), that will implement touch events, like touchesBegan. You can add it to the view after that.
This way you'll use composition instead subclassing (which was the request).
Why don't you guys try SSEventListener?
You don't need to create any gesture recognizer and separate your logic apart to another method. SSEventListener supports setting listener blocks on a view to listen for single tap gesture, double tap gesture and N-tap gesture if you like, and long press gesture. Setting a single tap gesture listener becomes this way:
[view ss_addTapViewEventListener:^(UITapGestureRecognizer *recognizer) { ... } numberOfTapsRequired:1];

Resources