swift - How to get back to viewcontroller in alertview -

i tried viewcontroller when user press go home in alertview , show me error ( libc++abi.dylib: terminating uncaught exception of type nsexception )

 @ibaction func roundbutton(sender: anyobject) {      //add alert     alertcontroller = uialertcontroller(title: "return home", message: "are sure???", preferredstyle: .alert)      let alertaction1 = uialertaction(title: "cancel", style: .default) { (action) in      }     let alertaction2 = uialertaction(title: "go home", style: .destructive) { (action) in          let nv = self.storyboard!.instantiateviewcontrollerwithidentifier("storyboardidentifier") as! viewcontroller         self.presentviewcontroller(nv, animated:true, completion:nil)     }       alertcontroller?.addaction(alertaction2)     alertcontroller?.addaction(alertaction1)      self.presentviewcontroller(alertcontroller!, animated: true, completion: nil)     //end alert  } 

since didn't provide information, there lot of possibilities. try cover of them.

let's presenting alert in bviewcontroller. , want aviewcontroller.

if aviewcontroller , bviewcontroller embedded in uinavgationcontroller, have connect unwind segue between bviewcontroller , aviewcontroller.

first, in aviewcontroller, add method:

@ibaction func unwind(segue: uistoryboardsegue) {  } 

in storyboard, control-drag bviewcontroller "exit" of `aviewcontroller , select "unwind:" aka method declared. should see

now give segue added identifier, "unwindtohome".

in uialertaction call closure, initiate segue:

self.performseguewithidentifier("unwindtohome", sender: self) 

and that's it!

if presenting bviewcontroller modally, things simpler, call dismissviewcontrolleranimated:

self.dismissviewcontrolleranimated(true, completion: nil)