Can't Use Nil for keys or values of PFObject - ios

Question

So I have this code.
#IBAction func updateRatelabel(sender: AnyObject) {
let rateValue = Int(rateSlider.value)
if rateValue == 0 {
rateLabel.text = "Budget (min.)"
}
else {
rateLabel.text = "$ \(rateValue)"
}
}
func createdoctor()
{
let doctors = PFObject(className: "doctors")
if doctorName.text?.characters.count > 5 {
doctorName.textColor = UIColor.redColor()
}
else {
let currentUser = String( PFUser.currentUser())
let rateValue = rateLabel.text
let rateValueInt = String(rateValue?.characters.dropFirst(2))
print(rateValueInt)
doctors["doctorName"] = doctorName.text
doctors["Rate"] = Int(rateValueInt)
doctors["doctorContent"] = doctorDetails.text
doctors["createdby"] = currentUser
doctors.saveInBackgroundWithBlock ({(success: Bool, error: NSError?) -> Void in
if error == nil {
print("created doctor")
}
else {
print("image \(error)")
}
let alert = UIAlertController(title: "Success", message: "New doctor Created" , preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
})
}
}
I am getting error when this code kicks in, this is the error that is happening
> 016-01-31 01:00:07.921 idoctortwo[3294:151254] Attempting to load the
> view of a view controller while it is deallocating is not allowed and
> may result in undefined behavior (<UIAlertController: 0x7f8258c8af80>)
> Optional(Swift.String.CharacterView(_core:
> Swift._StringCore(_baseAddress: 0x00007f8258c9b9c2, _countAndFlags: 4,
> _owner: Optional(Swift._HeapBufferStorage<Swift._StringBufferIVars, Swift.UInt16>)))) 2016-01-31 01:00:12.771 idoctortwo[3294:151254] ***
> Terminating app due to uncaught exception
> 'NSInvalidArgumentException', reason: 'Can't use nil for keys or
> values on PFObject. Use NSNull for values.'
I managed to find out that the following line of code is the culprit
doctors["Rate"] = Int(rateValueInt)
if I do this
doctors["Rate"] = rateValueInt
I have no error but my Parse the column is a number column hence the effort to make it as a number.
EDIT
2016-01-31 03:58:11.222 iLegaltwo[3662:186816] Attempting to load the
view of a view controller while it is deallocating is not allowed and
may result in undefined behavior ()
Optional(Swift.String.CharacterView(_core:
Swift._StringCore(_baseAddress: 0x00007fb2c3667472, _countAndFlags: 4,
_owner: Optional(Swift._HeapBufferStorage)))) 2016-01-31 03:58:30.728 iLegaltwo[3662:186900]
[Error]: invalid type for key createdby, expected *_User, but got
string (Code: 111, Version: 1.12.0) image Optional(Error Domain=Parse
Code=111 "invalid type for key createdby, expected *_User, but got
string" UserInfo={code=111, temporary=0, error=invalid type for key
createdby, expected *_User, but got string,
NSLocalizedDescription=invalid type for key createdby, expected
*_User, but got string})
EDIT after modifications for the above error:
func createCase()
{
let cases = PFObject(className: "Cases")
if caseName.text?.characters.count > 5
{
caseName.textColor = UIColor.redColor()
}
else
{
let currentUser = String( PFUser.currentUser())
let rateValue = rateLabel.text
let rateValueInt = String(rateValue?.characters.dropFirst(2))
print(rateValueInt)
cases["CaseName"] = caseName.text
cases["Rate"] = Int(rateValueInt) ?? Int(0)
cases["CaseContent"] = caseDetails.text
cases["createdby"] = currentUser
cases.saveInBackgroundWithBlock ({(success: Bool, error: NSError?) -> Void in
if error == nil
{
print("created case")
}
else
{
print("image \(error)")
}
self.performSelectorOnMainThread("success", withObject: nil, waitUntilDone: true)
})
}
}
func success() {
let alert = UIAlertController(title: "Success", message: "New doctor Created" , preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
}

Answer 1

Can't touch the UI from the background thread
Push the view controller from the main thread. Culprit:
saveInBackgroundWithBlock...
self.presentViewController
Solutions
- use `performSelectorOnMainThread`
- use dispatch_async(dispatch_get_main_queue(), ^(void) { } })
Example
Replace alert creation by
self.performSelectorOnMainThread("success", withObject: nil, waitUntilDone: true)
and add this method:
func success() {
let alert = UIAlertController(title: "Success", message: "New doctor Created" , preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
}

Answer 2

Dictionary key/value can't be nil
Int("someString") doesn't return an Int but an optional Int?.
The documentation lists these accessors as Array Accessors, while in reality, using key/value, they should be considered Dictionary Accessors.
Thus you should treat PFObject is a dictionary wrapper: can't pass nil for either key nor value. You store objects in a dictionary, not optionals.
Twist
Int(rateValueInt) ends up being a Int?, because of the Int(rateValueInt) conversion.
Solution
doctors["Rate"] = Int(rateValueInt) ?? Int(0)
This will explicitly substitute an Int in case Int(rateValueInt) can't be unwrapped.