swift parse query skip null column - swift

I'm doing a PFQuery to get uploaded file in column. How to get that file and if the column is null there's no file do something else ?
If the column is null i'm getting error message the query wont go well.
fatal error: unexpectedly found nil while unwrapping on Optional value
query.findObjectsInBackgroundWithBlock {
(objects, error) -> Void in
if error == nil
{
for object in objects! {
self.files.append(object.objectForKey("file") as! PFFile)
}
I want to get that file but if the column was null do something else ? how can i do that?


Use optional unwrapping with if let file = ... as? PFFile {
} else {
}

Related

How to read null values from SQLite database using Swfit [duplicate]

I am reading from a dbtable and get an error at a specific position of the table. My sql is ok, because I could already read from the same table, but at a specific row I get an error and I would like to know howto handle this error. I am not looking for a solution to solve my db-issue, I am just looking for handling the error, so it doesn't crash.
I have the following code :
let unsafepointer=UnsafePointer<CChar>(sqlite3_column_text(statement, 2));
if unsafepointer != nil {
sText=String.fromCString(unsafepointer)! // <<<<<< ERROR
} else {
sText="unsafe text pointer is nil !";
}
I get an error:
"fatal error: unexpectedly found nil while unwrapping an Optional value"
at line marked with <<<<<< ERROR.
The unsafe pointer's value is not nil:
pointerValue : 2068355072
How can I handle this error, so my app is not crashing ?

Another possible solution is this:
let unsafepointer=UnsafePointer<CChar>(sqlite3_column_text(statement, 2));
var sText = "unsafe text pointer is nil !";
if unsafepointer != nil{
if let text = String.fromCString(unsafepointer) as String?{
sText = text;
}
}

let statementValue = sqlite3_column_text(statement, 2)
var sText = withUnsafeMutablePointer(&statementValue) {UnsafeMutablePointer<Void>($0)}

if sqlite3_column_text(statement, 2) != nil {
print("do something")
} else {
YourString = ""
}

Key value pair not getting added to my dictionary in Swift

I am trying to add an item to my dictionary. profileURL contains the correct value as I have seen from what the print statement gives me but for some reason the dictionary is not creating a new entry with it. Any solutions?
Here is my code:
storageRef.downloadURL(completion: {(url, error) in
if error != nil {
return
}
if let profileURL = url?.absoluteString {
print("SHOULD BE DATA HERE: ", profileURL)
databaseValues["profileUrl"] = profileURL
}
})

Cannot assign values from functions to dictionary array Swift 4

I've encountered the following error in two different scenarios that may be related. The error is:
lldb Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
This is the code for the first scenario:
db.collection("properties").getDocuments()
{
(querySnapshot, err) in
if let err = err
{
print("Error getting documents: \(err)");
}
else
{
for document in querySnapshot!.documents {
var propertyData = [String:[String]]()
let listingType = (document.get("listingType") as! [String])
propertyData["listingType"]![0] = listingType[0]
}
}
}
I am trying to get a list of properties that I have already set in Firestore. I can print the listingType variable to the console and it successfully prints "Sale". However when I assign the variable it then gives that error.
I have experienced the same issue when using the location manager functions. If I get the user's current location coordinates, when I try to add those coordinates to a global dictionary it throws the same error. I am writing the code in Swift 4.

You can't just assign something to [0] since the array is initially nil
if propertyData["listingType"] == nil {
propertyData["listingType"] = [listingType[0]] //Create a new array with the string
} else {
propertyData["listingType"]![0] = listingType[0]
}

query if the data is found - Parse & Swift 3

I'm trying to develop an app that provide User sign up and within the UI I want to query if the email is exists or not.
The problem is since I change from swift 2 to swift 3 I got these errors
var query = PFObject(className:"User")
query.whereKey("email", equalTo: email)
query.findObjectsInBackground {
(objects, error) -> Void in
if error == nil {
// The find succeeded.
print("Successfully retrieved \(objects!.count) scores.")
// Do something with the found objects
if let objects = objects {
for object in objects {
print(object.objectId)
}
}
} else {
// Log details of the failure
print("Error: \(error!) \(error!.userInfo)")
}
}
/Users/**************/SignUpSenderViewController.swift:49:9:
Value of type 'PFObject' has no member 'whereKey'
/Users/i*************/SignUpSenderViewController.swift:50:9:
Value of type 'PFObject' has no member 'findObjectsInBackground'
any suggestion to solve this challenge ?

I dont know what documentation you checked but the query has to be done this way...
let query = PFQuery(className:"_User")

Retrieve Data in Parse

I have searched through a number of similar topics but have not found a solution as of yet. I am using Parse social and using the login files.
I get the following error:
"AnyObject?" is not convertible to 'String'
I am very new to Swift & Parse - I believe this is the correct method of retrieving data, so please correct me if I am wrong.
var userObjectID = PFUser.currentUser()!.objectId!
var query = PFQuery(className:"User")
query.getObjectInBackgroundWithId("\(userObjectID)") {
(userInfo: PFObject?, error: NSError?) -> Void in
if error == nil && userInfo != nil {
println(userInfo)
let userScore = userInfo["level"] as! String
} else {
println(error)
}
}
Below is the database on Parse

I think you need to unwrap the PFObject you receive:
let userScore = userInfo!["level"] as! String