Swift - How Can I Show The MKPolyline For A Tracked Event - ios

Question

My problem is that when a jog has been completed, I can not present the recordedMapView with a full polyline that had tracked the location in an after exercise report.
Currently I am able to persist the data from tracking a run in the first view controller appearing in app, then in the detail view controller I fetch the data and unwrap/assign them to the respective variables, however, I am not sure where I go wrong in the code that is not allowing a polyline to appear. The map region does seem to be getting set properly as the map zooms in and out dynamically to fit the entire journey.
What could be the issue for why the polyline is not being presented and is there a solution to the code that I have provided to correct this problem?
var context : NSManagedObjectContext?
var runTimestamp : NSDate?
var runDuration : NSNumber?
var runDistance : NSNumber?
var runLocations : NSOrderedSet?
var locationTimeStamp : NSDate?
var locationLatitude : NSNumber?
var locationLongitude : NSNumber?
override func viewDidLoad()
{
super.viewDidLoad()
guard let context = context, finishedLocations = fetchLocation ( context ), finishedRun = fetchRun ( context ) else { return }
for location in finishedLocations
{
if let timestamp = location.timestamp, latitude = location.latitude, longitude = location.longitude
{
locationTimeStamp = timestamp
locationLatitude = latitude
locationLongitude = longitude
}
}
for run in finishedRun
{
if let timeStamp = run.timestamp, duration = run.duration, distance = run.distance, locations = run.locations
{
runTimestamp = timeStamp
runDuration = duration
runDistance = distance
runLocations = locations
}
}
updateUI ()
}
func loadMapView()
{
if runLocations!.count > 0
{
recordedMapView.region = mapRegion()
let colorSegments = MulticolorPolylineSegment.colorSegments(forLocations: runLocations!.array as! [Location])
recordedMapView.addOverlays(colorSegments)
}
else
{
let alertController = UIAlertController( title: "Error", message: "No Locations Saved", preferredStyle: .Alert )
let alertAction = UIAlertAction ( title: "Error", style : .Default , handler : nil )
alertController.addAction( alertAction )
presentViewController ( alertController, animated: true, completion: nil )
}
}
func mapRegion() -> MKCoordinateRegion
{
let initialLocation = runLocations!.firstObject as! Location
var minLat = initialLocation.latitude! .doubleValue
var minLng = initialLocation.longitude!.doubleValue
var maxLat = minLat
var maxLng = minLng
let locations = runLocations!.array as! [Location]
for location in locations
{
minLat = min( minLat, location.latitude! .doubleValue )
minLng = min( minLng, location.longitude!.doubleValue )
maxLat = max( maxLat, location.latitude! .doubleValue )
maxLng = max( maxLng, location.longitude!.doubleValue )
}
return MKCoordinateRegion(
center: CLLocationCoordinate2D( latitude : ( (minLat + maxLat)/2 ) , longitude : ( (minLng + maxLng)/2 ) ),
span : MKCoordinateSpan ( latitudeDelta: ( (maxLat - minLat)*1.1) , longitudeDelta: ( (maxLng - minLng)*1.1) )
)
}
func polyline() -> MKPolyline
{
var coordinates = [CLLocationCoordinate2D]()
let locations = runLocations!.array as! [Location]
for location in locations
{
coordinates.append( CLLocationCoordinate2D(latitude: (location.latitude!.doubleValue), longitude: (location.longitude!.doubleValue)) )
}
return MKPolyline(coordinates: &coordinates, count: runLocations!.count)
}
func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer
{
let polyline = overlay as! MulticolorPolylineSegment
let renderer = MKPolylineRenderer(polyline: polyline)
renderer.strokeColor = polyline.color
renderer.lineWidth = 3
return renderer
}

Answer 1

Swift 3.x:
What I see you don't add the polyLine properly into mapView.
Change your polyline function like below;
func polyline()
{
if theJourney != nil && theJourney!.coords != nil{
var coordinates = [CLLocationCoordinate2D]()
let locations = runLocations!.array as! [Location]
for location in locations
{
coordinates.append( CLLocationCoordinate2D(latitude: (location.latitude!.doubleValue), longitude: (location.longitude!.doubleValue)) )
}
}
let polyline = MKPolyline(coordinates: &coordinates, count: runLocations!.count)
mapView.add(polyline)
}
And MKMapView's rendererFor method with code below;
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
let renderer = MKPolylineRenderer(overlay: overlay)
renderer.strokeColor = UIColor.green
renderer.lineWidth = 3
return renderer
}
That's should work. Please let me know.