I have subclassed UIButton and want to call a delegate method just once when the button goes into the highlighted state and call it again just once when it goes into the unhighlighted state:
override var isHighlighted: Bool {
didSet {
if isHighlighted {
delegate?.buttonHighlightStateDidChange(highlighted: true)
} else {
delegate?.buttonHighlightStateDidChange(highlighted: false)
}
}
}
However when I touch down on the button it seems that didSet is getting repeatedly called. What am I doing wrong here? How can I call the delegate method just once?
I would recommend against using your subclass in this way. UIControl has a builtin mechanism for getting callbacks in response to control events:
func registerActions(for button: UIButton) {
button.addTarget(self, action: #selector(MyClass.buttonIsHighlighted(sender:)), for: .touchDown)
button.addTarget(self, action: #selector(MyClass.buttonIsUnHighlighted(sender:)), for: .touchUpInside)
button.addTarget(self, action: #selector(MyClass.buttonIsUnHighlighted(sender:)), for: .touchUpOutside)
}
func buttonIsHighlighted(sender: UIButton) {
// highlighted
}
func buttonIsUnHighlighted(sender: UIButton) {
// unhighlighted
}
Related
I have a simple button in a cocoapods library, I need to change the tintcolor when it is isHighlighted however isHighlighted gets called but didset or willset never get called.
I am ofcourse setting my button to be highlighted, and I call this function after I dequeue my tableview cell
func setupCell() {
let myCustomButton = UIButton.button(title: "Button")
myCustomButton.isHighlighted = true
}
My UIButton Extension
extension UIButton {
public static func button(title: String) -> UIButton {
let button = UIButton(type: .custom)
button.setTitle(title, for: .normal)
button.setTitleColor(UIColor.gray, for: .normal)
return button
}
override open var isHighlighted: Bool {
didSet {
print("Never gets here, ever!")
}
}
}
How can I trigger didSet? Is there any other way apart from setting isHighlighted to true?
I have four custom UIButton, I applied button image radio (checked and checked). four button I have separate action method I can change the Image easily but if I checked first button another three button need uncheck. it should react like radio button.
Here, below my code
#IBAction func first_scheme(_ sender: Any) {
bRec = !bRec
if (bRec == true) {
firstscheme_button.setImage(UIImage(named: "uncheck.png"), for: .normal)
} else {
firstscheme_button.setImage(UIImage(named: "check.png"), for: .normal)
}
}
If you have 4 radio buttons at all times, you can put them in an array.
var radioButtons: [ButtonType] = [r1, r2, r3, r4]
You can now access the button in a loop and set the values for the other button to 'unchecked'.
func setRadioButtons(button: ButtonType) {
for radioButton in radioButtons {
if radioButton !== button {
radioButton.setImage(UIImage(named: "uncheck.png"), for: .normal)
}
}
}
#IBAction func first_scheme(_ sender: Any) {
bRec = !bRec
if bRec {
firstscheme_button.setImage(UIImage(named: "uncheck.png"), for: .normal)
} else {
firstscheme_button.setImage(UIImage(named: "check.png"), for: .normal)
}
setRadioButtons(button: sender)
}
alternate method
If all you want to do is check the button clicked and uncheck the other buttons, the logic is simpler.
Create the common action for all radio buttons as well create the IBOutletcollection for your all UIButtons ,
var radioButtons: [UIButton] = [r1, r2, r3, r4]
finally execute the common method as
func setRadioButtons(button: UIButton) {
for getradioButton in radioButtons {
getradioButton.setImage(UIImage(named: "uncheck.png"), for: .normal)
}
button.setImage(UIImage(named: "check.png"), for: .normal)
}
I suggest you set tags on the buttons with the simple tag property, and then you save it from a generic listener.
//first button selected
var lastTag = 0
#IBAction func first_scheme(_ sender: UIButton) {
buttonArray[lastTag].setImage(UIImage(named: "uncheck.png"), for: .normal)
lastTag = sender.tag
sender.setImage(UIImage(named: "check.png"), for: .normal)
}
You Can override isSelected variable in the custom UIButton and set the image depend on the isSelected value.
class customButton: UIButton {
override var isSelected: Bool {
willSet {
self.setImage(UIImage.init(named: "checked"), for: .normal)
}
didSet {
self.setImage(UIImage.init(named: "unchecked"), for: .normal)
}
}
}
After making 4 IBOutlets and 4 IBActions for the four custom UIButtons. you can easily select and unselect the buttons and apply your custom behaviour.
#IBAction func firstButtonAction(_ sender: Any) {
if let button = sender as? customButton {
button.isSelected = !button.isSelected
}
secondButton.isSelected = false
thirdButton.isSelected = false
fourthButton.isSelected = false
}
The following code is located inside a subclass of UIView
I am setting up a cancelButton inside a closure:
private var cancelButtonClosure: UIButton = {
...
button.addTarget(self, action: #selector(cancel(_:)), for: .touchUpInside)
...
}()
And at first I instantiated the button inside a function like so:
func showConfirmationView(...) {
...
let cancelButton = self.cancelButtonClosure
...
addSubview(cancelButton)
...
}
However this resulted in the cancel function not being called at all (even though the layout was right and the button was highlighting)
So I made these change:
Removed the addTarget part from the cancelButtonClosure
Added the addTarget part inside the showConfirmationView function
So it looked like that:
func showConfirmationView(...) {
...
let cancelButton = self.cancelButtonClosure
cancelButton.addTarget(self, action: #selector(cancel(_:)), for: .touchUpInside)
...
addSubview(cancelButton)
...
}
It worked: the cancel function was called; but I don't know why. I'm really curious to know why what I did before did not work. Thanks for your insights!
Check your implementation because a setup like this works as expected:
private var cancelButton: UIButton = {
let btn = UIButton(type: .system)
btn.setTitle("Cancel", for: .normal)
btn.addTarget(self, action: #selector(cancelSomething(_:)), for: .touchUpInside)
return btn
}()
#objc func cancelSomething(_ sender: UIButton) {
print("Something has to be cancelled")
}
override func viewDidLoad() {
super.viewDidLoad()
showConfirmationView()
}
func showConfirmationView() {
cancelButton.sizeToFit()
cancelButton.center = view.center
view.addSubview(cancelButton)
}
I have a class where written is a function creating my button:
LoginButton.swift
func createButton() {
let myButton: UIButton = {
let button = UIButton()
button.addTarget(self, action: #selector(Foo().buttonPressed(_:)), for: .touchUpInside)
}()
}
Now in my second class, Foo.swift, I have a function that just prints a statement
Foo.swift
#objc func buttonPressed(_ sender: UIButton) {
print("button was pressed")
}
When ran I get no errors except when I try to press the button, nothing happens. Nothing prints, the UIButton doesn't react in any way. Really not sure where the error occurs because Xcode isn't printing out any type of error or warning message.
The action method is called in the target object. Thus, you have either to move buttonPressed to the class which contains createButton or to pass an instance of Foo as a target object.
But note that a button is not the owner of its targets. So, if you just write:
button.addTarget(Foo(), action: #selector(buttonPressed(_:)), for: .touchUpInside)
This will not work, because the Foo object is immediately released after that line. You must have a strong reference (e.g. a property) to Foo() like
let foo = Foo()
func createButton() {
let myButton: UIButton = {
let button = UIButton()
button.addTarget(foo, action: #selector(buttonPressed(_:)), for: .touchUpInside)
}()
}
You are missing with target. So make instant of target globally and make use of it as target for button action handler.
class ViewController: UIViewController {
let foo = Foo()
override func viewDidLoad() {
super.viewDidLoad()
createButton()
}
func createButton() {
let myButton: UIButton = {
let button = UIButton(frame: CGRect(x: 0, y: 0, width: 100, height: 50))
button.backgroundColor = UIColor.red
button.setTitle("Tap me", for: .normal)
button.addTarget(self.foo, action: #selector(self.foo.buttonPressed(_:)), for: .touchUpInside)
return button
}()
myButton.center = self.view.center
self.view.addSubview(myButton)
}
}
Class Foo:
class Foo {
#objc func buttonPressed(_ sender: UIButton) {
print("button was pressed")
}
}
Just pass Selector as function argument.
func createButtonWith(selector: Selector) {
let myButton: UIButton = {
let button = UIButton()
button.addTarget(self, action: selector), for: .touchUpInside)
}()
}
And call this function like below...
createButtonWith(selector: #selector(Foo().buttonPressed(_:)))
I have placed three buttons together in a view each of which will have a different profile image. I need all three buttons to highlight when touch begins on any individual one so that the three together appear to be one button. I have tried the following code but it does not work. Any ideas?
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(normalTap))
tapGesture.numberOfTapsRequired = 1
friendsBtn1.addGestureRecognizer(tapGesture)
func normalTap(sender: UITapGestureRecognizer){
if sender.state == .began {
friendsBtn2.isHighlighted = true
friendsBtn3.isHighlighted = true
}
if sender.state == .ended {
friendsBtn2.isHighlighted = false
friendsBtn3.isHighlighted = false
}
print("Normal tap")
}
i think no need to UITapGesture you can manage like this way.
First you need to set highlighted image to the button And Setup button event as per bellow.
override func viewDidLoad() {
super.viewDidLoad()
friendsBtn2.setImage(UIImage(named: "highlighted.png"), for: .highlighted)
friendsBtn3.setImage(UIImage(named: "highlighted.png"), for: .highlighted)
friendsBtn1.addTarget(self, action: #selector(YourViewController.touchDownEvent), for: .touchDown)
friendsBtn1.addTarget(self, action: #selector(YourViewController.touchUpInsideEvent), for: .touchUpInside)
}
After that add method touchDownEvent(),touchUpInsideEvent() in your ViewController.
func touchDownEvent() {
self.allButtonHighlighted(fleg: true)
}
func touchUpInsideEvent() {
self.allButtonHighlighted(fleg: false)
}
func allButtonHighlighted( fleg: Bool) {
friendsBtn2.isHighlighted = fleg
friendsBtn3.isHighlighted = fleg
}
I hope it will Works.
I did solve the problem. Here is the code.
[friendsBtn1, friendsBtn2, friendsBtn3].forEach { button in
button?.addTarget(self, action:#selector(highlightAllButtons(sender:)), for: .touchDown)
button?.addTarget(self, action:#selector(unhighlightAllButtons(sender:)), for: [.touchUpInside, .touchUpOutside])
}
func highlightAllButtons(sender: UIButton) {
[friendsBtn1, friendsBtn2, friendsBtn3].forEach { button in
button.isHighlighted = true
}
}
func unhighlightAllButtons(sender: UIButton) {
[friendsBtn1, friendsBtn2, friendsBtn3].forEach { button in
button.isHighlighted = false
}
}
Try [button setSelected:YES]; for all the three buttons in your button action.