SwiftUI - Can I use a completion handler in Button action? - swift

Question

I have a form that gets a new user's name and zip code. When the user presses Save, I use Core Location to take the zip code and find the associated city and state. At that point I want a completion handler to save the form data along with the city and state.
But for some reason, the completion part isn't kicking in. I'm still trying to figure out completion handlers but I thought I got pretty close... (obviously I need to deal with error handling and the code could be more concise.)
Button(action: {
self.getCityStateFromPostalCode(zip: self.zip, completion: {
//This isn't getting called
let newCustomer = Customer(context: self.moc)
newCustomer.custName = self.name
newCustomer.custZip = self.zip
newCustomer.custState = self.state
newCustomer.custCity = self.city
self.appDelegate.saveContext()
})
}) {
Text("Save")
}
func getCityStateFromPostalCode(zip: String, completion: #escaping () -> ()) {
let geocoder = CLGeocoder()
var city = ""
var state = ""
geocoder.geocodeAddressString(zip) { (placemarks, error) in
if let placemark = placemarks?[0] {
if placemark.postalCode == zip {
city = placemark.locality!
state = placemark.administrativeArea!
self.city = city
self.state = state
}
}
}
}

Answer 1

In your function you're not calling the completion parameter:
func getCityStateFromPostalCode(zip: String, completion: #escaping () -> ()) {
let geocoder = CLGeocoder()
var city = ""
var state = ""
geocoder.geocodeAddressString(zip) { (placemarks, error) in
if let placemark = placemarks?[0] {
if placemark.postalCode == zip {
city = placemark.locality!
state = placemark.administrativeArea!
self.city = city
self.state = state
}
}
completion() // <- add this (may be moved depending on the `error` parameter
}
}