ios - swift - UIImageWriteToSavedPhotosAlbum causes EXC_BAD_ACCESS -

i saving image in camera roll. when done, should make reference image in db. logic pretty simple

class mydownloader{     let db : dbhelper = dbhelper.sharedinstance      func downloadfilefromserver(){         let urlstring = "http://any-image.jpg"         let url = nsurl(string: urlstring)         let data = nsdata(contentsofurl: url!)         let image = uiimage(data: data!)         if(image == nil){             println("no downloaded image")         }         else{             // works no errors             --> --> uiimagewritetosavedphotosalbum(image, nil, nil, nil);              // never works              --> --> uiimagewritetosavedphotosalbum(image, self, "image:didfinishsavingwitherror:contextinfo:", nil)         }     }      func image(image: uiimage, didfinishsavingwitherror error: nserrorpointer, contextinfo:unsafepointer<void>) {         if error != nil {             // error feedback goes here         }         else{             // save db reference here         }     } } 

the method below

uiimagewritetosavedphotosalbum(image, self, "image:didfinishsavingwitherror:contextinfo:", nil) 

always returns exc_bad_access

you should make mydownloader inherit nsobject selector part of objective-c's runtime.