Passing arguments to #selector method in swift [duplicate]

问题

I want to pass multiple argument to a function while I click an image. Here is my code

var param1 = 120
var param2 = "hello"
var param3 =  "world"

let image: UIImage = UIImage(named: "imageName")!
 bgImage = UIImageView(image: image)

let singleTap = UITapGestureRecognizer(target: self, action:#selector(WelcomeViewController.tapDetected(_:secondParam:thirdParam:)))
singleTap.numberOfTapsRequired = 1
bgImage!.userInteractionEnabled = true
bgImage!.addGestureRecognizer(singleTap)

calling function

func tapDetected(firstParam: Int, secondParam: String, thirdParam: String) {
print("Single Tap on imageview")
            print(firstParam)  //print 120
            print(secondParam) // print hello
            print(thirdParam) /print world
        }

How can I pass arguments so that I can get correct values?

回答1:

You can't. From the documentation:

A gesture recognizer has one or more target-action pairs associated with it.
...
The action methods invoked must conform to one of the following signatures:
- (void)handleGesture;
- (void)handleGesture:(UIGestureRecognizer *)gestureRecognizer;

You may use instance variables to pass the parameters.

回答2:

In swift2 you can't pass parameters in actions. You may just use class properties:

var param1 = 120
var param2 = "hello"
var param3 = "world"
let image: UIImage = UIImage(named: "imageName")!
var bgImage: UIImageView?

override func viewDidLoad() {
    super.viewDidLoad()

    bgImage = UIImageView(image: image)
    let singleTap = UITapGestureRecognizer(target: self, action: #selector(WelcomeViewController.tapDetected))
    singleTap.numberOfTapsRequired = 1
    bgImage!.userInteractionEnabled = true
    bgImage!.addGestureRecognizer(singleTap)
}

calling function

func tapDetected() {
    print("Single Tap on imageview")
    print(param1) // print 120
    print(param2) // print hello
    print(param3) // print world
}

来源：https://stackoverflow.com/questions/38328956/passing-arguments-to-selector-method-in-swift

标签

swift

swift2

uitapgesturerecognizer