Swift optional issue

Question

I am getting following error in compiler -

(position: CLLocationCoordinate2D) -> GMSMarker is not convertible to (position: CLLocationCoordinate2D) -> GMSMarker!.

Please help me to resolve it.

The code that gives this error is -

let location = CLLocationCoordinate2D(latitude: Double(latitudeVal!)!, longitude: Double(longitudeVal!)!)
let locationMarker = GMSMarker(position: location)

Where latitudeVal & longitudeVal are string values from server.

Thanks in advance.

Have you tried `if let`? like: `if let foo = (position: CLLocationCoordinate2D) {//code}` — Maysam, May 02 '16 at 11:15
Take a look at [this Q&A](http://stackoverflow.com/questions/32170456/what-does-fatal-error-unexpectedly-found-nil-while-unwrapping-an-optional-valu) that I co-wrote on how to safely deal with optionals. — Hamish, May 02 '16 at 11:32

score 1 · Answer 1 · edited May 23 '17 at 12:25

This is a bug of the Swift compiler optimization. See 'UIFont' is not convertible to 'UIFont?'.

To fix this, you can turn off 'Whole Module Optimization' in Build Settings -> Optimization Level -> (Debug/Release).

Alternatively, you can instead change your code to the following without turning off the 'Whole Module Optimization'.

let locationMarker = GMSMarker.init(position: location)

Hope this help.

score 0 · Answer 2 · answered May 02 '16 at 11:23

0

Apply below code, its working fine at my side.

let location = CLLocationCoordinate2DMake((latitudeVal as NSString).doubleValue, (longitudeVal as NSString).doubleValue)
let locationMarker = GMSMarker(position: location)

Hope this will work for you.

answered May 02 '16 at 11:23

Jigar Tarsariya

3,189
3
14
38

I have tried all of the above methods, none worked. I have the same code in 3 places and it shows compiler error on 2 places. I don't understand whats wrong. The latitude,longitude values are accessed from models - eg.city.lat. In 3 places 3 different models are used. – OSD May 02 '16 at 14:16

score 0 · Answer 3 · answered May 02 '16 at 11:27

the equation let locationMarker = GMSMarker(position: location), left of equation is type of GMSMarker!, right of the equation is type of GMSMarker. So you can not assign the right to the left。 you can change like let locationMarker: GMSMarker = GMSMarker(position: location) or let locationMarker = GMSMarker(position: location)!. you can try.

score 0 · Answer 4 · answered May 02 '16 at 11:32

You should unwrap your optionals.

    guard let long = longitudeVal else {
        print("No longitude provided")
        return
    }

    guard let lat = latitudeVal else {
        print("No latitude provided")
        return
    }

    guard let longVal = Double(long) else {
        print("Longitude contains an invalid value")
        return
    }

    guard let latVal = Double(lat) else {
        print("Latitude contains an invalid value")
        return
    }

    let location = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    let locationMarker = GMSMarker(position: location)

Take a look at Early Exit

score 0 · Answer 5 · answered May 02 '16 at 17:17

0

Ok, finally i solved it :) :-

let locationMarker = GMSMarker()
locationMarker.position = location

Hope it won't make any difference in the working of the code.

Thank you all!

answered May 02 '16 at 17:17

OSD

131
1
10

Swift optional issue

5 Answers5