如何在Swift 3的UIView类中使用performSegue

Question

I have an UIView class that contains a UILabel . I have added a UITapGestureRecognizer for the UILabel and want to do a performSegue to open a new UIViewController on tap of the UILabel . The problem is that I can't use performSegue in UIView class.

Can anyone please help to use performSegue in UIView class?

I have added a tap gesture to my label as,

nameLabel.isUserInteractionEnabled = true

let tap = UITapGestureRecognizer(target: self, action: #selector(tapFunction))  
tap.numberOfTapsRequired = 1
tap.numberOfTouchesRequired = 1
tap.isEnabled = true
nameLabel.addGestureRecognizer(tap)

Now in my tapFunction,

func tapFunction(sender:UITapGestureRecognizer) {
    print("tap working")
    self.performSegue(withIdentifier: "memberSegue", sender: self)
}

But I get an error:

"Value of type UIViewController has no member performSegue"

as it is an UIView Class.

Answer 1

You should try and separate any functionality from your UIViews . A best practice is your UIViewControllers to be responsible for any functionality in your app and your UIViews to be used only for displaying elements. Thus I would suggest that you make your nameLabel a property in your UIView , so that you can access it from your UIViewController after instantiating the UIView . Then the code in your UIViewController should look like this:

let yourView = new YourView()
let tap = UITapGestureRecognizer(target: self, action: #selector(tapFunction))
tap.numberOfTapsRequired = 1
tap.numberOfTouchesRequired = 1
tap.isEnabled = true
yourView.nameLabel.addGestureRecognizer(tap)

and you would have your tap() function in your UIViewController .

Answer 2

Make delegate in UIView Class and used to where you are using UIView in YourController class

 protocol UIViewDelegate { 
     func tapFunction() //this function will be use in controller class which uiview are using
 }

 var delegate: UIViewDelegate?

 func tapFunction(sender:UITapGestureRecognizer) {
     delegate?.tapFunction()
 }

 class YourController: UIViewController, UIViewDelegate {
     let yourView = YourView()
     yourView.delegate = self

     func tapFunction() {
         self.performSegue(withIdentifier: "memberSegue", sender: self)
     }
 }

Answer 3

you can do it by protocol and delegate. Because actually you can not do it from UIView you should always do it from controller.

/// add this protocol in your project
protocol ViewProtocol {
    func performSegueFromView()
}

class View : UIView {

    /// add this line to your view
    var delegate : ViewProtocol?


    /// replace your tap function with this
    func tapFunction(sender:UITapGestureRecognizer) {

        print("tap working")

        self.delegate?.performSegueFromView()
    }

}


class ViewController : UIViewController, ViewProtocol {

    override func viewDidLoad() {

        /// create view
        let view = View()
        /// assign view delegate
        view.delegate = self

    }

    /// delegate function
    func performSegueFromView() {
        ///peform segue from controller because you can not do this from uiview anyway
        self.performSegue(withIdentifier: "memberSegue", sender: self)
    }

}

Answer 4

I would suggest you to add action for that tap gesture instead of segue.

TapRecognizer.addTarget(self, action: #selector(YourFunc))

Samle Func:

func YourFunc(){                  
        let storyBoardHome = UIStoryboard(name: "", bundle: nil)        
     let memberController = storyBoardHome.instantiateViewController(withIdentifier: "") 
           self.navigationController?.pushViewController(memberController, animated: true)
                }

Refer This : https://stackoverflow.com/a/26366366/6818278

Answer 5

the error you wrote is wrong, UIViewController's do have that method. Your error must be "UIVIew has no member...", as for the solution you just need to get a reference to whatever UIViewController is using this specific view.

Then use that reference to call your perform method.

For example, if your custom View is being added programmatically, you can add an extra property to your class like

weak var myVC : UIViewController?

then after instantiating it just assign it to this property.

Then the perform segue becomes:

myVC?.performSegue....

---

Alternatively you can just add the tap gesture recognizer from the UIViewController that is using this view, then have the view show it from there.

---

Or you could just use:

UIApplication.shared.keyWindow?.rootViewController.performSegue...

But if you do, you should be careful as this one might have unintended consequences depending on what you are presenting and which is the current rootViewController.