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 = ""
}
Related
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]
}
Despite checking for nil, I am getting fatal error: unexpectedly found nil while unwrapping an Optional value the error is being caught in the conditional (first line below)
if (obj.prop != nil && obj.prop?.otherprop != nil) {
anotherObj.yetanotherprop = (obj.prop?.otherprop as NSURL).absoluteString
}
I have also tried this with if let as follows (xcode highlights the 2nd let as being where the unexpected nil is found):
if let objA = obj.prop,
let otherProp = objA.otherPROP {
anotherObj.yetanotherprop = (otherProp as NSURL).absoluteString
}
Why don't either of these work?!
I am getting the source object (obj in both cases above) from a 3rd party library that is written in objective c. I am suspecting that I am checking for nil wrong somehow?
So in writing this up I think I sort of figured it out. I don't knwo why the first one doesn't work, but the second works as:
if let objA = obj.prop,
let otherProp = objA?.otherPROP {
anotherObj.yetanotherprop = (otherProp as NSURL).absoluteString
}
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 = ""
}
I am trying to retrieve contact names, here's how:
func getContactNames() {
let adbk : ABAddressBook? = ABAddressBookCreateWithOptions(nil, nil).takeRetainedValue()
let people = ABAddressBookCopyArrayOfAllPeople(adbk).takeRetainedValue() as [ABRecord]
for person in people {
contactList.append(ABRecordCopyCompositeName(person).takeRetainedValue() as String)
}
}
When all contacts do have names it works, although when there are some contacts without names, app crashes and I get:
fatal error: unexpectedly found nil while unwrapping an Optional value
I tried using ? like this:
let contact2 = (ABRecordCopyCompositeName(person)?.takeRetainedValue() as? String)
if contact2 != nil {
contactList.append(contact2!)
}
Then I would always get nil.
Any ideas what I am doing wrong?
In my experience you have to do it step-by-step: first check if ABRecordCopyCompositeNameis not nil and then take it and convert to string.
if let tmpName = ABRecordCopyCompositeName(person) {
let contact2 = tmpName.takeRetainedValue() as String
contactList.append(contact2)
}
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 {
}