ios - Swift PrepareForSegue NSIndexPath error -

i want prepare segue via:

override func prepareforsegue(segue: uistoryboardsegue?, sender: anyobject?) {     if segue?.identifier != "fromopenchatstologin" {         if let controller: chatviewcontroller? = segue?.destinationviewcontroller as? chatviewcontroller {             if let cell: onlineusercell? = sender as? onlineusercell {                 let user = oneroster.userfromrosteratindexpath(indexpath: tableview.indexpathforcell(cell!)!)                 controller!.recipient = user             }         }     } } 

where onlineusercell custom cell. also, that's userfromrosteratindexpath:

class func userfromrosteratindexpath(indexpath indexpath: nsindexpath) -> xmppusercoredatastorageobject {     return sharedinstance.fetchedresultscontroller()!.objectatindexpath(indexpath) as! xmppusercoredatastorageobject } 

so, when select cell crashes with:

fatal error: unexpectedly found nil while unwrapping optional value 

on line:

let user = oneroster.userfromrosteratindexpath(indexpath: tableview.indexpathforcell(cell!)!) 

what wrong? how can fix it?

first of all, swift introduced type inference, , best practices use properly, write code this

if let controller = segue?.destinationviewcontroller as? chatviewcontroller {    if let cell = sender as? onlineusercell {    } } 

also should set exception breakpoint in xcode (here), see more you're crashing.

in case in

override func prepareforsegue(segue: uistoryboardsegue, sender: anyobject?)

you should use following statement :

if segue.identifier == "fromopenchatstologin" { } else { } 

your login viewcontroller doesn't require user, therefore crashed at

let user = oneroster.userfromrosteratindexpath(indexpath: tableview.indexpathforcell(cell)!) 

because there no cell, , sender in prepareforsegue not cell.

for second issue, fix easy.

you sending oneroster.userfromrosteratindexpath(indexpath: indexpath) in

performseguewithidentifier("fromuserslisttochatview", sender: oneroster.userfromrosteratindexpath(indexpath: indexpath)) 

so don't need cell or since have user object !

set recipient :

controller?.recipient = sender as? xmppusercoredatastorageobject 

just replace prepareforsegue method following , work:

if segue.identifier == "fromopenchatstologin" { } else {     let controller = segue.destinationviewcontroller as? chatviewcontroller              controller?.recipient = sender as? xmppusercoredatastorageobject }