passing string from firebase realtime database request - swift

Question

How can I pass the string userImage which I get from a firebase realtime database request? I can not just use return userImage. It says Unexpected non-void return value in void function. I want the userImage as result and paste it to XXXXXX.
...
func datenBankAbfrage() {
print("datenbankabfrage getriggert")
dic = [:]
for name in myFeed.myArray1[0..<myFeed.myArray1.count] {
ref = Database.database().reference().child("placeID/\(name)")
ref.observe(.value) { (snapshot) in
self.dic[name] = []
var specificNameVideos = [importComment]()
for video in snapshot.children.allObjects as! [DataSnapshot] {
let Object1 = video.value as? [String: AnyObject]
let timestampDate = NSDate(timeIntervalSince1970: Double(Object1?["userTime"] as! NSNumber)/1000)
let dateFormatter = DateFormatter()
dateFormatter.timeZone = NSTimeZone.local
dateFormatter.dateFormat = "dd.MM.YY hh:mm"
let time = dateFormatter.string(from: timestampDate as Date)
print(time + "Uhr")
let userName = Object1?["userName"]
...
let kommentarCount = Object1?["kommentarCount"]
let userID = Object1?["userID"]
//print(userID!)
ViewComments.commentIDNew = commentId as! String
func wertBerechnen(completion: #escaping (String) -> Void) {
self.ref = Database.database().reference()
self.ref.child("user/\(userID!)").observeSingleEvent (of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let userImage = value?["picture"] as? String ?? ""
completion(userImage)
})
}
wertBerechnen { userImage in
let video = importComment(
userName: userName as! String, userGroup: userGroup as! String,
userComment: userComment as! String, userTime: userTime as! String,
userLikes: userLikes as! Int, commentId: commentId as! String, placeID: placeID as! String, kommentarCount: kommentarCount as? Int, userImage: userImage)
specificNameVideos.append(video)
}
}
self.dic[name] = specificNameVideos
let tem = Array(self.dic.values).flatMap { $0 } // You can also sort allComments with userTime property
self.table = tem.sorted { $0.userTime! > $1.userTime! }
self.tableView.reloadData()
}
myFeed.myArray1 = []
}
...

Answer 1

You can use a completion handler to return the userImage string:
func wertBerechnen(completion: #escaping (String) -> Void) {
self.ref = Database.database().reference()
self.ref.child("user/\(userID!)").observeSingleEvent (of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let userImage = value?["picture"] as? String ?? ""
completion(userImage)
})
}
Then you can call it like this:
wertBerechnen { userImage in
let video = importComment(
userName: userName as! String, userGroup: userGroup as! String,
userComment: userComment as! String, userTime: userTime as! String,
userLikes: userLikes as! Int, commentId: commentId as! String, placeID: placeID as! String, kommentarCount: kommentarCount as? Int, userImage: userImage)
specificNameVideos.append(video)
}
self.dic[name] = specificNameVideos
let tem = Array(self.dic.values).flatMap { $0 }
self.table = tem.sorted { $0.userTime! > $1.userTime! }
self.tableView.reloadData()
}
}
You need to reload the tableView data inside the wertBerechnen completion handler:
func wertBerechnen(completion: #escaping (String) -> Void) {
self.ref = Database.database().reference()
self.ref.child("user/\(userID!)").observeSingleEvent (of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let userImage = value?["picture"] as? String ?? ""
completion(userImage)
})
}
Then you can call it like this:
wertBerechnen { userImage in
let video = importComment(
userName: userName as! String, userGroup: userGroup as! String,
userComment: userComment as! String, userTime: userTime as! String,
userLikes: userLikes as! Int, commentId: commentId as! String, placeID: placeID as! String, kommentarCount: kommentarCount as? Int, userImage: userImage)
specificNameVideos.append(video)
self.tableView.reloadData()
}
self.dic[name] = specificNameVideos
let tem = Array(self.dic.values).flatMap { $0 }
self.table = tem.sorted { $0.userTime! > $1.userTime! }
}
}