Cannot avoid optional() for string print statements? - swift

Question

I have a data struct which contains some string parameters. The struct is below:
struct pulledMessage{
var convoWithUserID: String
var convoWithUserName: String
}
I have a function which assigns a value to variables based on the values within a particular pulledMessage. For some more complicated, out-of-the-scope-of-the-question, reasons, these values come from [pulledMessage] array. The pulledMessage always changes in the actual function but for illustration purposes I will write it as a constant:
var messageArray = [pulledMessage]()
func assignValues(){
messageArray.append(pulledMessage(convoWithUserID: "abc123", convoWithUserName: "Kevin"))
let convoWithUserID = messageArray[0].convoWithUserID
let convoWithUserName = messageArray[0].convoWithUserName
print(convoWithUserID) //returns optional("abc123")
print(convoWithUserName) // returns optional("Kevin")
}
I have tried adding ! to unwrap the values in different ways:
messageArray[0]!.convoWithUserID
This tells gives me an error that I cannot unwrap a non-optional type of pulledMessage.
messageArray[0].convoWithUserID!
This gives me an error that I cannot unwrap a non-optional type of String.
This stack question suggests utilizing if let to get rid of the optional:
if let convoWithUserIDCheck = messageArray[0].convoWithUserID{
convoWithUserID = convoWithUserIDCheck
}
This gives me a warning that there is no reason to do if let with a non-optional type of string. I have no idea how to get it to stop returning the values wrapped by optional().
Update: The more complicated, complete code
The SQL Database functions:
class FMDBManager: NSObject {
static let shared: FMDBManager = FMDBManager()
let databaseFileName = "messagesBetweenUsers.sqlite"
var pathToDatabase: String!
var database: FMDatabase!
override init() {
super.init()
let documentsDirectory = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString) as String
pathToDatabase = documentsDirectory.appending("/\(databaseFileName)")
}
func loadMessageData(){//will need a struct to load the data into a struct
if openDatabase(){
let query = "select * from messages order by messageNumber asc"
do{
print(database)
let results: FMResultSet = try database.executeQuery(query, values: nil)
while results.next(){
let message = pulledMessage(convoWithUserID: String(describing: results.string(forColumn: "convoWithUserID")), convoWithUserName: String(describing: results.string(forColumn: "convoWithUserName")), messageString: String(describing: results.string(forColumn: "messageString")), senderID: String(describing: results.string(forColumn: "senderID")), timeSent: String(describing: results.string(forColumn: "timeSent")), messageNumber: Int(results.int(forColumn: "messageNumber")))
if messagesPulled == nil{
messagesPulled = [pulledMessage]()
}
messagesPulled.append(message)
print("The message that we have pulled are \(message)")
}
}
catch{
print(error.localizedDescription)
}
database.close()
}
}
}
Running the population of the data at the onset of app launch:
func applicationDidBecomeActive(_ application: UIApplication) {
// if FMDBManager.shared.createDatabase() {
// FMDBManager.shared.insertMessageData()
// }else{
// print("Not a chance, sonny")
// FMDBManager.shared.insertMessageData()
// }
FMDBManager.shared.loadMessageData()
}
Organizing the SQL data in order:
struct pulledMessage{//global struct
var convoWithUserID: String
var convoWithUserName: String
var messageString: String
var senderID: String
var timeSent: String
var messageNumber: Int
}
var messagesPulled: [pulledMessage]!
var messageConvoDictionary = [String: [pulledMessage]]()
//For the individual message convos
var fullUnorderedMessageArray = [[pulledMessage]]()
var fullOrderedMessageArray = [[pulledMessage]]()
//For the message table
var unorderedLastMessageArray = [pulledMessage]()
var orderedLastMessageArray = [pulledMessage]()
//For the table messages... FROM HERE..........................................
func organizeSQLData(messageSet: [pulledMessage]){
var i = 0
var messageUserID = String()
while i < messageSet.count{
if (messageSet[i]).convoWithUserID != messageUserID{
print("It wasn't equal")
print(messageSet[i])
messageUserID = messageSet[i].convoWithUserID
if messageConvoDictionary[messageUserID] != nil{
messageConvoDictionary[messageUserID]?.append(messageSet[i])
}else{
messageConvoDictionary[messageUserID] = []
messageConvoDictionary[messageUserID]?.append(messageSet[i])
}
i = i + 1
}else{
messageConvoDictionary[messageUserID]?.append(messageSet[i])
i = i + 1
}
}
}
func getLastMessages(messageSet: [String:[pulledMessage]]){
for (_, messages) in messageSet{
let orderedMessages = messages.sorted(by:{ $0.timeSent.compare($1.timeSent) == .orderedAscending})
let finalMessage = orderedMessages[0]
unorderedLastMessageArray.append(finalMessage)
}
print(unorderedLastMessageArray)
}
func orderLastMessage(messageSet: [pulledMessage]){
orderedLastMessageArray = messageSet.sorted(by:{ $0.timeSent.compare($1.timeSent) == .orderedDescending})
messagesListTableView.reloadData()
print("It wasn't\(orderedLastMessageArray)")
}
func getMessagesReady(){//for observer type function calls
organizeSQLData(messageSet: messagesPulled)
getLastMessages(messageSet: messageConvoDictionary)
orderLastMessage(messageSet: unorderedLastMessageArray)
//This one is for the individual full convos for if user clicks on a cell... its done last because its not required for the page to show up
orderedFullMessageConvos(messageSet: messageConvoDictionary)
let openedMessageConversation = fullOrderedMessageArray[(indexPath.row)]//not placed in its appropriate location, but it is just used to pass the correct array (actually goes in a prepareforSegue)
}
override func viewDidLoad() {
super.viewDidLoad()
getMessagesReady()
}
Then segue to the new controller (passing openedMessageConversation to messageConvo) and run this process on a button click:
let newMessage = pulledMessage(convoWithUserID: messageConvo[0].convoWithUserID, convoWithUserName: messageConvo[0].convoWithUserName, messageString: commentInputTextfield.text!, senderID: (PFUser.current()?.objectId)!, timeSent: String(describing: Date()), messageNumber: 0)
messageConvo.append(newMessage)
let newMessageSent = PFObject(className: "UserMessages")
newMessageSent["convoWithUserID"] = newMessage.convoWithUserID
newMessageSent["convoWithUserName"] = newMessage.convoWithUserName
newMessageSent["messageString"] = newMessage.messageString
newMessageSent["senderID"] = newMessage.senderID
let acl = PFACL()
acl.getPublicWriteAccess = true
acl.getPublicReadAccess = true
acl.setWriteAccess(true, for: PFUser.current()!)
acl.setReadAccess(true, for: PFUser.current()!)
newMessageSent.acl = acl
newMessageSent.saveInBackground()
It is the newMessageSent["convoWithUserID"] and newMessageSent["convoWithUserName"] that read with the optional() in the database.

Answer 1

So it turns out that the reason for this stems from the function run from loadMessageData. The use of String(describing: results.string(forColumn:) requires an unwrapping of results.String(forColumn:)!. This issue propagated throughout the data modification for the whole app and caused the optional() wrapping for the print statements that I was seeing.