How do I call a button function when the button is not being pressed

Question

I have an IBAction connected to a button, and I wanted to know if there is any way to run that function even if the button is not being pressed. This is what I tried...

Note: I am using swift for this project.

//I get an error when I type this code?
self.buttonPressed()

@IBAction func buttonPressed(sender: AnyObject) {

    print("Called Action")

}

You need to pass a "sender" argument. The convention is that methods begin with a lowercase letter, classes with an uppercase letter. — zaph, May 01 '15 at 12:35
If `sender` is not used in the action you can pass any object, `self` is common. If `sender` is used you must pass an object that is acceptable to the action. — zaph, May 01 '15 at 12:49

score 20 · Accepted Answer · edited Feb 13 '20 at 02:06

20

Make your sender argument optional and pass nil to ButtonPressed.

self.ButtonPressed( nil )


@IBAction func ButtonPressed( sender: AnyObject? ) {
    println("Called Action")
}

edited Feb 13 '20 at 02:06

Samuel Liew

76,741
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answered May 01 '15 at 12:59

Satachito

5,838
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Chackle · Answer 2 · 2020-05-01T07:57:31.803

10

One way would be to link your button up to its respective interface builder button and pass it into your function when you call it.

@IBOutlet weak var yourButton: UIButton!

self.buttonPressed(yourButton)

@IBAction func buttonPressed(sender: AnyObject) {
    print("Called Action")
}

Alternatively, define your function like so, then you'll be able to call your method the same way as you did before:

@IBAction func buttonPressed(sender: AnyObject? = nil) {
    print("Called Action")
}

// Call your method like this
self.buttonPressed()

// or this
self.buttonPressed(sender: nil)

edited May 01 '20 at 07:57

answered May 01 '15 at 13:15

Chackle

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@satachito Yeah, I'm really liking optional parameters in swift! Nice and clean code :) – Chackle May 01 '15 at 14:05
The '= nil' didn't work for me. What does that do exactly, btw? – NYC Tech Engineer Jul 22 '15 at 03:21
2

@NYCTechEngineer the '= nil' will only work if the type is defined as optional (the ? at the end of AnyObject). It basically means that if the method is called without any parameters it will by default set `sender` to nil. Does that make sense? – Chackle Jul 22 '15 at 08:10
@Chackle That actually makes more sense. I was trying to pass nil to the call, maybe that's why it wasn't working. All I have to do is call the function without passing any parameters, and it will automatically send in nil, right? – NYC Tech Engineer Jul 24 '15 at 15:34
@NYCTechEngineer That's exactly correct! :) Nice and clean, isn't it? – Chackle Jul 24 '15 at 15:37
@Chackle, it is pretty sweet, can't wait to try it out! – NYC Tech Engineer Jul 24 '15 at 15:39

Matthew Quiros · Answer 3 · 2015-05-01T13:02:35.910

Your ButtonPressed function needs an argument sender and yet you're not passing any when you call it. However, if you're doing this programatically, then you obviously don't have a sender.

Two ways to get around this:

Make the sender parameter an optional (AnyObject? instead of AnyObject) and invoke self.ButtonPress(nil). I just tried this and it works.
Put all the button press function in a separate function, e.g., performButtonPress(). Call it from inside the IBAction outlet, and if you want to press the button programatically, directly call performButtonPress().

score 1 · Answer 4 · answered Sep 01 '17 at 07:52

1

Call a button action using the following format: Swift 3

@IBAction func buttonSelected(_ sender: UIButton) {
        print("Butten clicked")
}

To call the button action:

let button = UIButton()
self.buttonSelected(button)

answered Sep 01 '17 at 07:52

Ram Madhavan

2,362
1
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score 0 · Answer 5 · answered Jan 04 '17 at 16:16

0

You need to use "self" as "sender", example:

self.buttonPressed (sender: self)

or a simpler version

buttonPressed (sender: self)

Both tested in Swift 3

answered Jan 04 '17 at 16:16

ooenomel2003

97
9

score 0 · Answer 6 · answered Jul 18 '18 at 13:32

    lazy var Button : UIBarButtonItem = {
      let barButtonItem = UIBarButtonItem(title: "Button", style: .done, target: self, action: #selector(btnSelection))
      return barButtonItem
    }()


    func btnSelection(){
     // Code
    }

    // Now you can call self.btnSelection() whenever you want

How do I call a button function when the button is not being pressed

6 Answers6