Firebase Element May not exist on a call, iOS, Swift -
i using firebase database , storage hold images , descriptions. @ moment have coded have 8 images , 8 descriptions. trying work out how if user selects4 pictures , puts in 4 descriptions allows called back. works fine 8 when add 4 , select table called crashes error 5th photo var doesn't hold anything.
below code using call data table , crashes.
func configurecell(post: post) { self.post = post self.carimages = [] if post.imageurl1 != "" { self.carimages.append(post.imageurl1) } if post.imageurl2 != ""{ self.carimages.append(post.imageurl2) } if post.imageurl3 != "" { self.carimages.append(post.imageurl3) } if post.imageurl4 != "" { self.carimages.append(post.imageurl4) } if post.imageurl5 != "" { print ("tony: \(post.imageurl5)") self.carimages.append(post.imageurl5) } if post.imageurl6 != "" { self.carimages.append(post.imageurl6) } if post.imageurl7 != "" { self.carimages.append(post.imageurl7) } if post.imageurl8 != "" { self.carimages.append(post.imageurl8) } and crash happens on imageurl5
import foundation import firebase class post { private var _imageurl1: string! private var _imageurl2: string! private var _imageurl3: string! private var _imageurl4: string! private var _imageurl5: string! private var _imageurl6: string! private var _imageurl7: string! private var _imageurl8: string! private var _postkey: string! private var _postref: databasereference! private var _photoinfo1: string! private var _photoinfo2: string! private var _photoinfo3: string! private var _photoinfo4: string! private var _photoinfo5: string! private var _photoinfo6: string! private var _photoinfo7: string! private var _photoinfo8: string! var profileimageurl: string { return _profileimageurl } var imageurl1: string { return _imageurl1 } var imageurl2: string { return _imageurl2 } var imageurl3: string { return _imageurl3 } var imageurl4: string { return _imageurl4 } var imageurl5: string { return _imageurl5 } var imageurl6: string { return _imageurl6 } var imageurl7: string { return _imageurl7 } var imageurl8: string { return _imageurl8 } var postkey: string { return _postkey } var photoinfo1: string { return _photoinfo1 } var photoinfo2: string { return _photoinfo2 } var photoinfo3: string { return _photoinfo3 } var photoinfo4: string { return _photoinfo4 } var photoinfo5: string { return _photoinfo5 } var photoinfo6: string { return _photoinfo6 } var photoinfo7: string { return _photoinfo7 } var photoinfo8: string { return _photoinfo8 } init(imageurl1: string, imageurl2: string, imageurl3: string, imageurl4: string, imageurl5: string, imageurl6: string, imageurl7: string, imageurl8: string, photoinfo1: string, photoinfo2: string, photoinfo3: string, photoinfo4: string, photoinfo5: string, photoinfo6: string, photoinfo7: string, photoinfo8: string) { self._imageurl1 = imageurl1 self._imageurl2 = imageurl2 self._imageurl3 = imageurl3 self._imageurl4 = imageurl4 self._imageurl5 = imageurl5 self._imageurl6 = imageurl6 self._imageurl7 = imageurl7 self._imageurl8 = imageurl8 self._photoinfo1 = photoinfo1 self._photoinfo2 = photoinfo2 self._photoinfo3 = photoinfo3 self._photoinfo4 = photoinfo4 self._photoinfo5 = photoinfo5 self._photoinfo6 = photoinfo6 self._photoinfo7 = photoinfo7 self._photoinfo8 = photoinfo8 } init(postkey: string, postdata: dictionary<string, anyobject>) { self._postkey = postkey if let imageurl1 = postdata["imageurl1"] as? string { self._imageurl1 = imageurl1 } if let imageurl2 = postdata["imageurl2"] as? string { self._imageurl2 = imageurl2 } if let imageurl3 = postdata["imageurl3"] as? string { self._imageurl3 = imageurl3 } if let imageurl4 = postdata["imageurl4"] as? string { self._imageurl4 = imageurl4 } if let imageurl5 = postdata["imageurl5"] as? string { self._imageurl5 = imageurl5 } if let imageurl6 = postdata["imageurl6"] as? string { self._imageurl6 = imageurl6 } if let imageurl7 = postdata["imageurl7"] as? string { self._imageurl7 = imageurl7 } if let imageurl8 = postdata["imageurl8"] as? string { self._imageurl8 = imageurl8 } if let photoinfo1 = postdata["photoinfo1"] as? string { self._photoinfo1 = photoinfo1 } if let photoinfo2 = postdata["photoinfo2"] as? string { self._photoinfo2 = photoinfo2 } if let photoinfo3 = postdata["photoinfo3"] as? string { self._photoinfo3 = photoinfo3 } if let photoinfo4 = postdata["photoinfo4"] as? string { self._photoinfo4 = photoinfo4 } if let photoinfo5 = postdata["photoinfo5"] as? string { self._photoinfo5 = photoinfo5 } if let photoinfo6 = postdata["photoinfo6"] as? string { self._photoinfo6 = photoinfo6 } if let photoinfo7 = postdata["photoinfo7"] as? string { self._photoinfo7 = photoinfo7 } if let photoinfo8 = postdata["photoinfo8"] as? string { self._photoinfo8 = photoinfo8 } _postref = dataservice.ds.ref_posts.child(_postkey) } } 
perhaps answer via example
we have post class private var that's optional - meaning contain value or nil. indicated string?
when external imageurl1 accessed may return value or may nil, again ? indicates that.
class post{ private var _imageurl1: string? var imageurl1: string? { return _imageurl1 } init(url: string?) { //this nil! self._imageurl1 = url } } let apost = post(url: "testurl") if apost.imageurl1 != nil { print(apost.imageurl1!) } //or preferred way unwraps optional automatically if let aposturl = apost.imageurl1 { print(aposturl) } else { print("it nil") } //here's nil example let bpost = post(url: nil) if let bposturl = bpost.imageurl1 { print(bposturl) } else { print("it nil") //prints nil }
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