Pass a parameter to prepareForSegue from function

Question

I have to functions, both of them trigger performSegueWithIdentifier with the same segue. But depending of which function was called I need to pass different parameters in prepareForSegue.

Some thing like

func first() {
  // do some stuff
  performSegueWithIdentifier("My segue", sender:AnyObject?)
}

func second() {
  // do some stuff
  performSegueWithIdentifier("My segue", sender:AnyObject?)
}

func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
  if segue.identifier == "My segue" {
        let destination = segue.destinationViewController as! MyController
        if functionFirstWasCalled {
           destination.property = value
        } else if functionSecondWasCalled {
           destination.property = anotherValue
        }
    }
}

Surely, I can do this by setting booleans from second() and first() and then checking them in prepareForSegue - but maybe there is some more elegant way to do this ?

this shud help you http://blog.xebia.com/understanding-the-sender-in-segues-and-use-it-to-pass-on-data-to-another-view-controller/ — Teja Nandamuri, Jul 18 '16 at 18:52
http://stackoverflow.com/questions/7864371/how-to-pass-prepareforsegue-an-object — Teja Nandamuri, Jul 18 '16 at 18:56
I saw both materials. I neither dont have object to pass, neither tag. — Alexey K, Jul 18 '16 at 18:58
you can pass the method name as string object. What else do you need ? — Teja Nandamuri, Jul 18 '16 at 18:59

Teja Nandamuri · Answer 1 · 2016-07-18T19:15:57.900

In objective -c you would do:

     [self performSegueWithIdentifier:@"segueNAme" sender:@"firstMethod"];

and you can access this message in the prepareForSegue method

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    if ([sender isEqualToString:@"firstMethod"]) {
        //firstMEthod called the segue
    }
}

The swift equivalent I think would be:

 self.performSegueWithIdentifier("segueNAme", sender: "firstMethod")

and

func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject) {
    if (sender == "firstMethod") {
        //firstMEthod called the segue
    }
}

My suggestion would be to instead of sending a plain string , send a dictionary type object that contains the methodName, className and some other params useful for future debugging.

score 0 · Answer 2 · answered Jul 18 '16 at 19:21

0

All you have to do is send a flag by sender attribute, something like this:

func first() {
    performSegueWithIdentifier("My segue", sender:true)
}

func second() {
   // do some stuff
   performSegueWithIdentifier("My segue", sender:false)
}

func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

  if segue.identifier == "My segue" {
     let destination = segue.destinationViewController as! MyController
     let isFirstFunctionCalled = sender as! Bool //  cast sender to bool
     if isFirstFunctionCalled {
         destination.property = value
     } else {
         destination.property = anotherValue
     }
   }

}

answered Jul 18 '16 at 19:21

Santiago Carmona González

1,019
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19

what if the OP has more than two methods ? In that case sending true or false will not work. – Teja Nandamuri Jul 18 '16 at 19:23
Passing the same type you can simply write `destination.property = sender as! Bool` since you know `sender` is always `Bool` – vadian Jul 18 '16 at 19:23
If the OP has more than two methods, you've to send a `String` or maybe an `Integer`. Both will work – Santiago Carmona González Jul 18 '16 at 19:25
@TejaNandamuri could be an enum, string, etc – Josh Jul 18 '16 at 20:19

score -1 · Answer 3 · answered Jul 18 '16 at 19:12

Simply set parallel properties in this View Controller which you then pass to the destination View Controller based on the function called. i.e:

var a = ""
var b = 0

func first() {
  // do some stuff
  a = "first function determined this variable."
  b = 1
  performSegueWithIdentifier("My segue", sender:AnyObject?)
}

func second() {
  // do some stuff
  a = "second function determined this variable."
  b = 182
  performSegueWithIdentifier("My segue", sender:AnyObject?)
}

func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
  if segue.identifier == "My segue" {
        let destination = segue.destinationViewController as! MyController
        if functionFirstWasCalled {
           destination.property = a
        } else if functionSecondWasCalled {
           destination.property = b
        }
    }
}

Pass a parameter to prepareForSegue from function

3 Answers3