Error in conversion from Swift 2 to Swift 3 - swift3

Question

This is the second and last section I am battling with converting Swift 2 to Swift 3
The old working code was
func calculateSegmentDirections(index: Int,
time: NSTimeInterval, routes: [MKRoute]) {
let request: MKDirectionsRequest = MKDirectionsRequest()
request.source = locationArray[index].mapItem
request.destination = locationArray[index+1].mapItem
request.requestsAlternateRoutes = true
request.transportType = .Automobile
let directions = MKDirections(request: request)
directions.calculateDirectionsWithCompletionHandler ({
(response: MKDirectionsResponse?, error: NSError?) in
if let routeResponse = response?.routes {
let quickestRouteForSegment: MKRoute =
routeResponse.sort({$0.expectedTravelTime <
$1.expectedTravelTime})[0]
var timeVar = time
var routesVar = routes
routesVar.append(quickestRouteForSegment)
timeVar += quickestRouteForSegment.expectedTravelTime
if index+2 < self.locationArray.count {
self.calculateSegmentDirections(index+1, time: timeVar, routes: routesVar)
} else {
self.showRoute(routesVar, time: timeVar)
self.hideActivityIndicator()
}
} else if let _ = error {
let alert = UIAlertController(title: nil,
message: "Directions not available.", preferredStyle: .Alert)
let okButton = UIAlertAction(title: "OK",
style: .Cancel) { (alert) -> Void in
self.navigationController?.popViewControllerAnimated(true)
}
alert.addAction(okButton)
self.presentViewController(alert, animated: true,
completion: nil)
}
})
}
The converted code is
func calculateSegmentDirections(index: Int,
time: NSTimeInterval, routes: [MKRoute]) {
let request: MKDirectionsRequest = MKDirectionsRequest()
request.source = locationArray[index].mapItem
request.destination = locationArray[index+1].mapItem
request.requestsAlternateRoutes = true
request.transportType = .Automobile
let directions = MKDirections(request: request)
directions.calculateDirectionsWithCompletionHandler ({
(response: MKDirectionsResponse?, error: NSError?) in
if let routeResponse = response?.routes {
let quickestRouteForSegment: MKRoute =
routeResponse.sort({$0.expectedTravelTime <
$1.expectedTravelTime})[0]
var timeVar = time
var routesVar = routes
routesVar.append(quickestRouteForSegment)
timeVar += quickestRouteForSegment.expectedTravelTime
if index+2 < self.locationArray.count {
self.calculateSegmentDirections(index+1, time: timeVar, routes: routesVar)
} else {
self.showRoute(routesVar, time: timeVar)
self.hideActivityIndicator()
}
} else if let _ = error {
let alert = UIAlertController(title: nil,
message: "Directions not available.", preferredStyle: .Alert)
let okButton = UIAlertAction(title: "OK",
style: .Cancel) { (alert) -> Void in
self.navigationController?.popViewControllerAnimated(true)
}
alert.addAction(okButton)
self.presentViewController(alert, animated: true,
completion: nil)
}
})
}
It throws an error on the line
directions.calculateDirectionsWithCompletionHandler ({
The error is
Cannot convert value of type '(MKDirectionsResponse?, NSError?) -> ()' to expected argument type 'MKDirectionsHandler' (aka '(Optional, Optional) -> ()')
If anyone can help me I would be very thankful!!

Answer 1

NSError was renamed to Error in Swift 3.0 This may fix your issue.
This code compiles for me:
func calculateSegmentDirections(index: Int,
time: TimeInterval, routes: [MKRoute]) {
let request: MKDirectionsRequest = MKDirectionsRequest()
request.source = locationArray[index].mapItem
request.destination = locationArray[index+1].mapItem
request.requestsAlternateRoutes = true
request.transportType = .automobile
let directions = MKDirections(request: request)
directions.calculate (completionHandler: {
(response: MKDirectionsResponse?, error: Error?) in
if let routeResponse = response?.routes {
let quickestRouteForSegment: MKRoute =
routeResponse.sorted(by: {$0.expectedTravelTime <
$1.expectedTravelTime})[0]
var timeVar = time
var routesVar = routes
routesVar.append(quickestRouteForSegment)
timeVar += quickestRouteForSegment.expectedTravelTime
if index+2 < self.locationArray.count {
self.calculateSegmentDirections(index+1, time: timeVar, routes: routesVar)
} else {
self.showRoute(routesVar, time: timeVar)
self.hideActivityIndicator()
}
} else
if let _ = error {
let alert = UIAlertController(title: nil,
message: "Directions not available.", preferredStyle: .alert)
let okButton = UIAlertAction(title: "OK",
style: .Cancel) { (alert) -> Void in
self.navigationController?.popViewControllerAnimated(true)
}
alert.addAction(okButton)
self.presentViewController(alert, animated: true,
completion: nil)
}
})
}