Method passed to UIButton#addTarget not called - ios

I'm going through Apple's iOS development with Swift tutorial and have gotten myself stuck on the 5th stage:
import UIKit
class RatingControl: UIStackView {
// MARK: Initialisation
override init(frame: CGRect) {
super.init(frame: frame)
setupButtons()
}
required init(coder: NSCoder) {
super.init(coder: coder)
setupButtons()
}
// MARK: Button action
#objc func ratingButtonTapped(button: UIButton) {
NSLog("Button pressed")
}
// MARK: Private methods
private func setupButtons() {
NSLog("setupButtons() called")
// Create the button
let button = UIButton()
button.backgroundColor = UIColor.red
// Add constraints
button.translatesAutoresizingMaskIntoConstraints = false
button.heightAnchor.constraint(equalToConstant: 44.0).isActive = true
button.widthAnchor.constraint(equalToConstant: 44.0).isActive = true
// Setup the button action
button.addTarget(self, action: #selector(RatingControl.ratingButtonTapped(button:)), for: .touchUpInside)
// Add the button to the stack
addArrangedSubview(button)
}
}
setupButtons is called and I see the message in Xcode's debug console, and the button appears as a red box on the simulator:
However, when I click on the button, nothing happens - no message is printed to the debug console.
I honestly have no clue how I would even begin debugging this, since everything compiles/runs without errors, and I've already tried placing debug messages around what seems to be the issue.
Does anyone have any ideas on what's going on?
EDIT: Here is where the class is being used, and the output in the console:

I have tested your code in Playgrounds, and it works as expected. Therefore I expect that you are using the RatingControl incorrectly. One possible bug might be that one of its superviews has isUserInteractionEnabled set to false. Check this example:
// A UIKit based Playground for presenting user interface
import PlaygroundSupport
import UIKit
class RatingControl: UIStackView {
// MARK: Initialisation
override init(frame: CGRect) {
super.init(frame: frame)
setupButtons()
}
required init(coder: NSCoder) {
super.init(coder: coder)
setupButtons()
}
// MARK: Button action
#objc func ratingButtonTapped(button: UIButton) {
print("Button pressed")
}
// MARK: Private methods
private func setupButtons() {
print("setupButtons() called")
// Create the button
let button = UIButton()
button.backgroundColor = UIColor.red
// Add constraints
button.translatesAutoresizingMaskIntoConstraints = false
button.heightAnchor.constraint(equalToConstant: 44.0).isActive = true
button.widthAnchor.constraint(equalToConstant: 44.0).isActive = true
// Setup the button action
button.addTarget(self, action: #selector(RatingControl.ratingButtonTapped(button:)), for: .touchUpInside)
// Add the button to the stack
addArrangedSubview(button)
}
}
class A: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
self.view.addSubview(RatingControl(frame: CGRect(x: 0, y: 0, width: 40, height: 40)))
// if you uncomment the following line, the button will stop working
// self.view.isUserInteractionEnabled = false
}
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = A()
If that's not the case, include the code in which you use the RatingControl, because that's where the bug lies.

It's working normally with me, I've put self.view.addSubview(button)
instead of addArrangedSubview(button) .

Related

swift cannot add target to UIButton

so this question is super simple, but i checked that like a 100 times but it still won't work.
Basically, when user taps on tableView cell, it open another VC with different views, depending whether or not user is owner of post.
First condition, works just fine, adding target to button, while when second is being executed, nothing happens
lazy var buttonsView = DetailButtonsView() // those are almost the same
lazy var addvertView = AdvertiseView()
// inside of buttonsView()
lazy var skipButton: UIButton = {
let button = UIButton()
button.setTitle("Пожаловаться", for: .normal)
button.setTitleColor(.mainColor, for: .normal)
button.titleLabel?.font = .getPoppinsMediumFont(on: 15)
return button
}()
override init(frame: CGRect) {
super.init(frame: .zero)
setupView() //set up constraints
}
//inside of AdvertiseView()
lazy var blackButton:UIButton = {
var button = UIButton()
button.layer.cornerRadius = 8
button.backgroundColor = .black
return button
}()
override init(frame: CGRect) {
super.init(frame: .zero)
setupView() //set up constraints
}
//
func setUpBottom() -> Void {
if dataInfo!.user_id! == UserSettings.userModel.id
{
self.backView.addSubview(addvertView) //also works
addvertView.snp.makeConstraints //works
{
(make) in
make.left.equalToSuperview()
make.top.equalTo(userView.snp.bottom).offset(24)
make.height.equalTo(450)
make.bottom.lessThanOrEqualTo(-34)
}
addvertView.blackButton.addTarget(self, action: #selector(blackButtonMethod), for: .touchUpInside) // does not add target
}
else {
backView.addSubview(buttonsView) //works
buttonsView.snp.makeConstraints { (make) in
make.left.right.equalToSuperview()
make.top.equalTo(userView.snp.bottom).offset(24)
make.bottom.lessThanOrEqualTo(-34)
}
buttonsView.skipButton.addTarget(self, action: #selector(toComplain), for: .touchUpInside) //works
}
#objc func toComplain(){ //works
let vc = ComplaintTypeViewController()
vc.advertID = dataInfo!.id!
navigationController?.pushViewController(vc, animated: true)
}
#objc func blackButtonMethod(){ //does not work
print("hello")
parameters["action"] = "hot"
parameters["advert_id"] = String(describing: dataInfo!.id)
updateAdvert(parameters: parameters)
}
The target is probably added, but you cannot interact with it. That usually happens when constraints/frame is not set right. I see that the skip button uses:
button.setTitle("Пожаловаться", for: .normal)
which will infer autolayout width/height.
I don't see black blackButton's autolayout constraints or label set anywhere.

UIBarButtonItem not Showing

So Im trying to create a UIBarButtonItem with a custom UIView by subclassing it like so.
import UIKit
import SnapKit
class LocationManager: UIBarButtonItem {
let createdView = UIView()
lazy var currentCityLabel: UILabel = {
let currentCityLabel = UILabel()
currentCityLabel.text = "Philadelphia, PA"
guard let customFont = UIFont(name: "NoirPro-SemiBold", size: 20) else {
fatalError("""
Failed to load the "CustomFont-Light" font.
Make sure the font file is included in the project and the font name is spelled correctly.
"""
)
}
currentCityLabel.adjustsFontForContentSizeCategory = true
return currentCityLabel
}()
lazy var downArrow: UIImageView = {
let downArrow = UIImageView()
downArrow.contentMode = .scaleAspectFit
downArrow.image = UIImage(named: "downArrow")
return downArrow
}()
override init() {
super.init()
setupViews()
}
#objc func setupViews(){
customView = createdView
createdView.addSubview(currentCityLabel)
currentCityLabel.snp.makeConstraints { (make) in
make.left.equalTo(createdView.snp.left)
make.top.bottom.equalTo(createdView)
}
createdView.addSubview(downArrow)
downArrow.snp.makeConstraints { (make) in
make.left.equalTo(currentCityLabel.snp.right).offset(5)
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
However, when I create it and assign it in my viewController I see nothing
import UIKit
class ViewController: UICollectionViewController {
override func viewDidLoad() {
super.viewDidLoad()
setupViews()
}
#objc func setupViews(){
guard let collection = collectionView else {
return
}
collection.backgroundColor = .white
let customLeftBar = LocationManager()
self.navigationController?.navigationItem.leftBarButtonItem = customLeftBar
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I've looked at other post and none seem to quite match my situation. I'm beginning to think it is because I didn't give the UIView a frame but I am not exactly sure how I would do that in this instance if that is the case. Anyone see anything I don't that could potentially help me solve this problem. Also setting a target doesn't work I tried two different ways and none of them triggers a thing
#objc func setupBarButtonItems(){
let customLeftBar = LocationManager()
customLeftBar.action = #selector(self.leftBarPressed)
customLeftBar.target = self
customLeftBar.customView?.isUserInteractionEnabled = true
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(self.leftBarPressed))
customLeftBar.customView?.addGestureRecognizer(tapGesture)
navigationItem.leftBarButtonItem = customLeftBar
}
#objc func leftBarPressed(){
print("left bar tapped")
}
Change your adding line from
self.navigationController?.navigationItem.leftBarButtonItem = customLeftBar
to
self.navigationItem.leftBarButtonItem = customLeftBar
When add the barItem, you need to add it via navigationItem of the ViewController, not NavigationController
EDITED for add the action
Your custom UIBarButtonItem is a Custom View's BarButtonItem, so the target and selector will not working.
You can add your custom action by adding a button into your customView, and send the action via closure
Init your closure
var didSelectItem: (() -> Void)?
Add the create button code in your #objc func setupViews()
let button = UIButton(type: .custom)
createdView.addSubview(button)
button.snp.makeConstraints { (maker) in
maker.top.bottom.leading.trailing.equalTo(createdView)
}
// button.backgroundColor = UIColor.cyan // uncomment this line for understand about the barbuttonitem's frame
button.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)
and add the function
#objc func didTap(_ button: UIButton) {
print("Did tap button")
}
In your viewController, you can get the tap action by
customLeftBar.didSelectItem = { [weak self] in
self?.leftBarPressed()
}
Unfortunately, your barbuttonitem's default frame is 30x30, so you must be set the frame for your barbuttonitem. If not, you can only catch the tap action in 30x30 area (uncomment the code for see it)

Delegate nil after setting it

I am using the delegate method but for some odd reason my delegate variable seems to be nil when I want to call the delegate method. I can't for the life of me figure out what I'm doing wrong
protocol ProfileProtocol {
func buttonTapped()
}
class ProfileView: UIView {
var delegate: ProfileProtocol?
#IBOutlet weak var button: UIButton!
override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setup()
}
override func awakeFromNib() {
configure()
}
func setup() {
...
}
#IBAction func buttonTapped(_ sender: UIButton) {
// delegate nil
delegate?.buttonTapped()
}
}
ProfileViewController (yes it conforms to ProfileProtocol):
override func viewDidLoad() {
swipeableView.nextView = {
createCardView()
}
}
func createCardView() -> UIView {
let cardView = ProfileView(frame: swipeableView.bounds)
cardView.delegate = self
let contentView = Bundle.main.loadNibNamed("ProfileCardView", owner: self, options: nil)?.first! as! UIView
contentView.translatesAutoresizingMaskIntoConstraints = false
contentView.backgroundColor = cardView.backgroundColor
cardView.addSubview(contentView)
activeCardView = cardView
return cardView
}
func buttonTapped() {
self.performSegue(withIdentifier: "profileToEmojiCollection", sender: self)
}
Whenever I tap the button in my ProfileView, my ProfileViewController should perform a segue, however the delegate method isn't even being called because delegate is nil when I tap the button
I like to keep my custom views modular, and do things programmatically, it avoids the use of a Xib.
You should keep your view's responsibilities and subviews to the view itself. Ultimately the View receiving the the action(s) should be responsible for calling the delegate's methods. Also nextView is a closure that returns a UIView: (() -> UIView?)? not a UIView, a call to a function in a closure is not an explicit return you should return the view: let view = createCardView() return view.
ProfileView.swift
import UIKit
protocol ProfileProtocol {
func buttonTapped()
}
class ProfileView: UIView {
var delegate: ProfileProtocol?
lazy var button: UIButton = {
let button = UIButton()
button.translatesAutoresizingMaskIntoConstraints = false
button.addTarget(self, action: #selector(buttonTapped(_:)), for: .touchUpInside)
button.setTitle("Profile Button", for: .normal)
button.backgroundColor = UIColor.black
return button
}()
override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func awakeFromNib() {
}
#objc func buttonTapped(_ sender: UIButton) {
// Check for a nil delegate, we dont want to crash if one is not set
if delegate != nil {
delegate!.buttonTapped()
} else {
print("Please set ProfileView's Delegate")
}
}
func setup() {
//setup subviews
self.addSubview(button)
button.widthAnchor.constraint(equalToConstant: 150).isActive = true
button.heightAnchor.constraint(equalToConstant: 50).isActive = true
button.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
button.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
}
}
You can create ProfileView's like any other UIView, but remember to set the Delegate of each of them after creation:
swipeableView.nextView = {
let view = createProfileView() //set properties during creation?
view.delegate = self
//set properties after creation?
//view.backgroundColor = UIColor.red
return view
}
ViewController.swift
import UIKit
class ViewController: UIViewController, ProfileProtocol {
lazy var profileView: ProfileView = {
let view = ProfileView()
view.backgroundColor = UIColor.lightGray
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
profileView.delegate = self
setup()
}
func buttonTapped() {
print("Do Something")
}
func setup() {
self.view.addSubview(profileView)
profileView.widthAnchor.constraint(equalTo: self.view.widthAnchor).isActive = true
profileView.heightAnchor.constraint(equalTo: self.view.heightAnchor, multiplier: 0.7).isActive = true
profileView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
profileView.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Modify class from another view controller

I'm using this code to customize UIButtons on my main ViewController and have placed it in it's own separate .swift file to be referenced wherever a UIButton exists. I want to be able to modify the properties of the MyCustomButton from within my main ViewController after a button is pressed.
For example, I press a button that's using the properties from MyCustomButton and its color changes.
I'm just getting into swift and am not greatly familiar with it's ins and outs quite yet. Any help is appreciated.
import Foundation
import UIKit
class MyCustomButton: UIButton {
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
self.layer.cornerRadius = 25;
self.layer.borderColor = UIColor.blackColor().CGColor
self.layer.borderWidth = 3
self.backgroundColor = UIColor.redColor()
self.tintColor = UIColor.whiteColor()
self.setTitle("", forState: UIControlState.Normal)
self.titleLabel?.numberOfLines = 0
self.titleLabel?.textAlignment = NSTextAlignment.Center
}
}
You can try to override layoutSubviews method:
override func layoutSubviews() {
super.layoutSubviews()
if self.state == UIControlState.Highlighted {
// DO WHAT YOU WANT
} else {
// RESET TO NORMAL
}
}
KVO or delegate protocol (Swift) would work! Either of these would allow you to manipulate the properties of your UI elements when a specific action occurs.
If you want to create new class and change button default behaivour, you should override functions like this one
override func pressesBegan(presses: Set<UIPress>, withEvent event: UIPressesEvent?) {
super.pressesBegan(presses, withEvent: event)
// add your implementation here
}
// func pressesCancelled
// func pressesChanged
// func pressesEnded
// etc.
But if you just want to change button properties on button tap, you can do it on button callback method:
override func viewDidLoad() {
super.viewDidLoad()
let button = UIButton(type: UIButtonType.System) as UIButton
button.frame = CGRectMake(100, 100, 100, 100)
button.setTitle("My Button", forState: UIControlState.Normal)
button.addTarget(self, action: "someAction:", forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(button)
}
func someAction(sender: UIButton) {
print("My Button tapped")
sender.setTitle("Now Tapped", forState: UIControlState.Normal)
}

GestureRecognizer not responding to tap

After initialisation of by subclass of UIImageView I have the following line of code:
self.userInteractionEnabled = true
self.addGestureRecognizer(UITapGestureRecognizer(target: self, action: "handleTap:"))
I created the necessary associated function :
func handleTap(gestureRecognizer: UITapGestureRecognizer) {
print("In handler")
}
On tapping on the view in question, "In handler was never printed to the console". I then removed the handler function to see if the compiler would complain about the missing function. It didn't.
I'm positively stumped. I'd truly appreciate any light people can shed on this.
Update: My class is actually a UIImageView as opposed to UIView
I was using UITapGestureRecognizer that I placed on a UILabel using Storyboard.
To get this to work I also had to place a checkmark in the block labeled: "User Interaction Enabled" in the UILabel Attributes Inspector in the Storyboard.
I discovered the answer after carefully combing through my code.
One of the parent views was created without supplying a frame:
While it's a noobish enough error to warrant deletion of this questions, odds are someone else will also have the same issue in the future...
Try this
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
self.view.userInteractionEnabled = true
var tapGesture = UITapGestureRecognizer(target: self, action: Selector("handleTap:"))
self.view.addGestureRecognizer(tapGesture)
}
func handleTap(sender : UIView) {
println("Tap Gesture recognized")
}
In addition to the other answers, this can be caused by adding the gesture recognizer to multiple views. Gesture recognizers are for single views only.
Reference: https://stackoverflow.com/a/5567684/6543020
I ran into this problem with programmatic views.
My UIView with the gesture recognizer had .isUserInteractionEnabled = true, but it did not respond to taps until I set .isUserInteractionEnabled = true for its parent views as well.
Most likely you add UIGestureRecognizer in wrong place. Here is working sample with UIView from storyboard. If you create your UIView dynamically then you should put this initialization in the correct constructor.
class TestView: UIView
{
override func awakeFromNib()
{
self.userInteractionEnabled = true
self.addGestureRecognizer(UITapGestureRecognizer(target: self, action: "handleTap:"))
}
func handleTap(gestureRecognizer: UITapGestureRecognizer)
{
println("Here")
}
}
I found the solution to this problem after lot of trial and error. So there are two solution two this
1. Either add the GestureRecognizer in viewDidLoad() and turn
userInteractionEnabled = true
2. If using computed property use lazy var instead of let to the property.
lazy var profileImageView: UIImageView = {
let iv = UIImageView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
iv.image = #imageLiteral(resourceName: "gameofthrones_splash")
iv.contentMode = .scaleAspectFill
iv.translatesAutoresizingMaskIntoConstraints = false
iv.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleSelectProfileImageView)))
iv.isUserInteractionEnabled = true
return iv
}()
For anyone that is still having problems even with all the previous answers, make sure you are using UITapGestureRecognizer instead of UIGestureRecognizer, I kept missing this detail while trying to find what was wrong.
This Code works for me with XCode 7.0.1
import UIKit
class ImageView: UIImageView {
init(frame: CGRect, sender: Bool, myImage: UIImage) {
super.init(frame: frame)
self.image = myImage
initBorderStyle(sender)
// enable user interaction on image.
self.userInteractionEnabled = true
let gesture = UITapGestureRecognizer(target: self, action: "previewImage:")
addGestureRecognizer(gesture)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
func previewImage(myGesture: UITapGestureRecognizer? = nil) {
print("i'm clicked")
}
private func initBorderStyle(sender: Bool) {
self.layer.masksToBounds = true
self.layer.cornerRadius = 8
self.layer.borderWidth = 0.5
self.layer.borderColor = getBorderColor(sender)
self.backgroundColor = getColor(sender)
}
func getBorderColor(sender: Bool) -> CGColor {
var result: CGColor
if sender {
result = UIColor(red: 0.374, green: 0.78125, blue: 0.0234375, alpha: 0.5).CGColor
} else {
result = UIColor(red: 0.3125, green: 0.6015625, blue: 0.828125, alpha: 0.5).CGColor
}
return result
}
}
Xcode 11.4 Swift 5.2
UserInteraction is enabled by default on Custom UIView
import UIKit
class YourView: UIView {
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
commonInit()
}
func commonInit() {
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(tapped))
self.addGestureRecognizer(tapGesture)
}
#objc func tapped() {
// do something
}
}
If you want to be notified elsewhere that the custom UIView has been tapped, then it is convenient to use a Notification.
It is best to create this as an extension to prevent it being Stringly typed.
extension Notification.Name {
static let DidTapMyView = Notification.Name("DidTapMyView")
}
In your custom UIView when the tapped function is called
#objc func tapped() {
NotificationCenter.default.post(name: .DidTapMyView, object: self)
}
In your UIViewController where you want to listen for the Notification:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(myViewWasTapped), name: .DidTapMyView, object: nil)
}
#objc func myViewWasTapped() {
// Notified here - do something
}
Here's a list of my findings in 2021, XCode 13:
Make sure both your view and all of its superviews have set width & height constraints(this one is crucial)
Set isUserInteractionEnabled = true for your view
There's no need to set explicit frame or isUserInteractionEnabled for other super views
In addition the above (userInteractionEnabled, clipsToBounds, etc.), if you are working with a view in a child view controller be sure that you have added it as a child with myParentViewController.addChild(myChildViewController) — we've run into a couple of situations now where visible views were not firing recognizing gestures because their view controllers hadn't been added, and presumably the VCs themselves were not being retained.
It turned out that my gesture didn't work because it was in a normal class, and not a subclass of UIView or anything.
I solved the issue by creating a subclass of UIView that I had an instance of in this normal class and placed the gesture logic in that.
I solved my issue by setting the height to the UIView.
optionView.heightAnchor.constraint(equalToConstant: 18).isActive = true
I had the same issue in my programmatically created ViewController. The bug was fixed when I added a backgroundColor to the view.
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .systemBackground
let tap = UITapGestureRecognizer(target: self.view, action: #selector(UIView.endEditing))
view.addGestureRecognizer(tap)
}
}

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