CODEWITHSUNDEEP
swiftannotationsmapkitmkannotation
Hugo75
Hugo75

Reputation: 249

swift - How sort alphabetically annotations array

My project is a map with a lot of annotations points, and user could look for a specific annotation thanks to a pickerView. All is fine except the list of all annotations points seems randomly displayed. I would like to sort the annotations alphabetically.

Here s my current working code :

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {

        return self.mapView.annotations[row].title ?? "No title"

    }

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        self.mapView.selectAnnotation(self.mapView.annotations[row], animated: true)
    }

I ve tried to implement this, but without any success...

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {

let sortedNames = self.mapView.annotations.sorted(by: {$0.title < $1.title})
        return sortedNames[row].title ?? "No title"

    }

I ve got this error:

Cannot convert value of type 'String??' to expected argument type 'UIContentSizeCategory'

Any hint would be greatly appreciated.

Upvotes: 3

Views: 865

Answers (2)

Jack Hopkins
Jack Hopkins

Reputation: 432

I'm aware this question is a bit old to answer but for anyone else having the issue the problem is that the String can not be optional. The fix it to either provide a default value or force unwrap it. For example this would be one solution to the question:

let sortedNames = self.mapView.annotations.sorted(by: { ($0.title ?? "") < ($1.title ?? "") }))
return sortedNames[row].title ?? "No title"

Upvotes: 8

dopiaza
dopiaza

Reputation: 146

I've just had exactly this error when trying to sort an array of a different class by a string property. The problem appears to be that the property you are sorting by is optional. Using a non-optional property works as expected, using an optional property gives the somewhat bizarre 'UIContentSizeCategory' error.

Something like this should do what you need:

   let sorted = self.mapView.annotations { (a1, a2) -> Bool in
            if let s1 = a1.title {
                if let s2 = a2.title {
                    return s1 > s2
                }
            }
            return false
        }

Upvotes: 0

Related Questions