how to programmatically fake a touch event to a UIButton?

Question

I'm writing some unit tests and, because of the nature of this particular app, it's important that I get as high up the UI chain as possible. So, what I'd like to do is programmatically trigger a button-press, as if the user had pressed the button in the GUI.

(Yes, yes -- I could just call the IBAction selector but, again, the nature of this particular app makes it important that I fake the actual button press, such that the IBAction be called from the button, itself.)

What's the preferred method of doing this?

Wilder

Could you explain why it's important that you fake the button touch rather than call the action method directly? There really is no practical difference. – Earful

@Jasarien: well, because there IS a difference! ;) In my app, several buttons use the same action method, and the method parses how to behave based on the button's tag. So the unit test, in addition to testing one particular code-path through the method, (a) needs to test them all and (b) also verifies that the buttons are correctly wired. In addition, it nicely abstracts my unit-test suite, as I can define unit tests as lines in a text file with something like this: "1 + 2 = 3" where "3" is the expected ending display, and everything before it is which button to push. – Wilder

well doesn't your action method have an (id)sender parameter? Couldn't you just call the method and pass the button as the sender? – Earful

Because of the abstract nature of my test harness, I don't KNOW the method that needs to be called for a particular button. I suppose I could dig into the button and get it, but doing sendActionsForControlEvents: does all this for me, with less opportunity for error, and keeps the test abstract and fitting with the design. – Wilder

Answer 1

It turns out that

[buttonObj sendActionsForControlEvents:UIControlEventTouchUpInside];

got me exactly what I needed, in this case.

EDIT: Don't forget to do this in the main thread, to get results similar to a user-press.

---

For Swift 3:

buttonObj.sendActions(for: .touchUpInside)

Wilder

Unfortunately, neither of these will always work - they rely on the receiver being a UIControl, rather than eg having a tap gesture. – Margetmargette

May i know how you set up your 'buttonObj'? How do you bind this to your UIButton? By ID? – Rinaldo

@TanSiongZhe, bottonObj is the UIButton. Whatever your reference to your button -- be it IBOutlet, iVar or what have you -- calling [myButton sendActionsForControlEvents: ... will do the expected thing which, in my case, was the desired thing. – Wilder

@ChenLiYong, One reason would be if the myActionMethod: is not public, and so you can't call it directly. – Menstruum

Xamarin: buttonObj.SendActionForControlEvents(UIControlEvent.TouchUpInside); – Radionuclide

Answer 2

An update to this answer for Swift

buttonObj.sendActionsForControlEvents(.TouchUpInside)

EDIT: Updated for Swift 3

buttonObj.sendActions(for: .touchUpInside)

Journey

I don't think this will work if the button is created in a XCTestCase without a run loop supporting. – Rothmuller

Answer 3

Swift 3:

self.btn.sendActions(for: .touchUpInside)

Gusto

This is just repeating the higher scored answers. – Footlambert

Answer 4

If you want to do this kind of testing, you’ll love the UI Automation support in iOS 4. You can write JavaScript to simulate button presses, etc. fairly easily, though the documentation (especially the getting-started part) is a bit sparse.

Randirandie

I understand Instruments, Jeff -- what I'm saying is: I want my unit-tests to run in the device in my pocket, without a laptop or XCode or Instruments handy. Or do you know the secret of running instruments on the device? ;) – Wilder

Answer 5

In this case, UIButton is derived from UIControl. This works for object derived from UIControl.

I wanted to reuse "UIBarButtonItem" action on specific use case. Here, UIBarButtonItem doesn't offer method sendActionsForControlEvents:

But luckily, UIBarButtonItem has properties for target & action.

 if(notHappy){        
         SEL exit = self.navigationItem.rightBarButtonItem.action;
         id  world = self.navigationItem.rightBarButtonItem.target;
         [world performSelector:exit];
 }

Here, rightBarButtonItem is of type UIBarButtonItem.

Countershaft

if you use UIBarButtonItem, you can just [self doAction:self.navigationItem.rightBarButtonItem]; //-doAction: is self.navigationItem.rightBarButtonItem's toggle action name. – Mccoy

Answer 6

For Xamarin iOS

btnObj.SendActionForControlEvents(UIControlEvent.TouchUpInside);

Reference

Scrophulariaceous

Answer 7

Swift 5:

class ViewController: UIViewController {
    @IBOutlet weak var theTextfield: UITextField!
    @IBOutlet weak var someButton: UIButton!
    override func viewDidLoad() {
        super.viewDidLoad()
        theTextfield.text = "Pwd"
        someButton.sendActions(for: .touchUpInside)
    }

    @IBAction func someButtonTap(_ sender: UIButton) {
        print("button tapped")
    }
}

Russellrusset

Answer 8

It's handy for people who write Unit Tests without UI Tests ;-)

Swift 5 way to solve it for UIBarButtonItem, which does not have sendAction method like UIButton etc.

extension UIBarButtonItem {
    func sendAction() {
        guard let myTarget = target else { return }
        guard let myAction = action else { return }
        let control: UIControl = UIControl()
        control.sendAction(myAction, to: myTarget, for: nil)
    }
}

And now you can simply:

let action = UIBarButtonItem(title: "title", style: .done, target: self, action: #selector(doSomething))
action.sendAction()

Inconsequent

Answer 9

Swift 4:

self .yourButton(self)

Buffon