Export file from iOS app to swift

I am new to Swift development and iOS in general. My application has a model that can be easily expressed as comma separated values ​​(csv), so naturally I want the user to be able to export the data as a csv file and open that file in another application. Since I didn't find any examples in Swift, I gave them a try on their own:

func ExportToCSV(delegate: UIDocumentInteractionControllerDelegate){
    let fileName = NSTemporaryDirectory().stringByAppendingPathComponent("myFile.csv")
    let url: NSURL! = NSURL(fileURLWithPath: fileName)

    var data  = "Date,Time,Count\n2014-11-21,14.00,42"

    data.writeToURL(url, atomically: true, encoding: NSUTF8StringEncoding, error: nil)
    if url != nil {
        let docController = UIDocumentInteractionController(URL: url)
        docController.UTI = "public.comma-separated-values-text"
        docController.delegate = delegate
        docController.presentPreviewAnimated(true)
    }
}

      

        
        
        
      

    

(the delegate parameter is the view that calls the function as in MyClass.ExportToCSV(self)

)

It basically works and I see the following views:

However, in the Simulator I get the following warning:

Unbalanced calls to begin/end appearance transitions for <QLRemotePreviewContentController: 0x7fcd720da800>.

      

        
        
        
      

    

and

Unknown activity items supplied: ("<QLPrintPageRenderer: 0x7fcd73861ee0>","<UIPrintInfo: 0x7fcd714b9030>")

      

        
        
        
      

    

when i press the action button and after a while

Communications error: <OS_xpc_error: <error: 0x10e032b10> { 
    count = 1, contents = "XPCErrorDescription" 
    => <string: 0x10e032f18> { length = 22, contents = "Connection interrupted" }
}>

      

        
        
        
      

    

and when I click "Mail" it crashes with the following error:

viewServiceDidTerminateWithError: Error Domain=_UIViewServiceInterfaceErrorDomain 
    Code=3 "The operation couldn’t be completed. (_UIViewServiceInterfaceErrorDomain error 3.)" 
    UserInfo=0x7fcd71631460 {Message=Service Connection Interrupted}
<MFMailComposeRemoteViewController: 0x7fcd73864aa0> timed out waiting for fence 
    barrier from com.apple.MailCompositionService

      

        
        
        
      

    

Although on the device itself, everything works as planned, so many of the errors threw me a little back. Is there a better solution?