iOS GoogleMaps tiles not shown correctly with GMSSyncTileLayer - ios

Question

I am building an app with a custom map using GoogleMaps tiles and GMSSyncTileLayer class. For some reason the tiles are not rendered as expected. Here one single tile is provided independent of the coordinates (for test purpose). The tiles are 256*256 (produced with MapTiler) and in this example I would expect this one tile being repeated and filling the space. I've tried different layer.tileSize = 1024 produces biggest tiles, 512 and 256 respectively smaller. Clearly I don't understand what is going in here. What would be the correct way of using tiles?
--- Edit ---
See my answer below - it might be that the problem was that I had those tiles in Assets.xcassets folder instead of normal folder. However did not test this as code now moved to MapKit instead.
class MapTileLayer: GMSSyncTileLayer {
override func tileFor(x: UInt, y: UInt, zoom: UInt) -> UIImage? {
// Return one specific 256*256 Map tile
let pathToImage = "MapTilesFolder/14/9370/4516"
if let tile = UIImage(named: pathToImage) {
return tile
} else {
return kGMSTileLayerNoTile
}
}
}
import UIKit
import GoogleMaps
class DetailViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let camera = GMSCameraPosition.camera(withLatitude: 62.545144, longitude: 25.905153, zoom: 16.0)
let mapView = GMSMapView.map(withFrame: self.view.frame, camera: camera)
mapView.mapType = GMSMapViewType.none
view = mapView
let layer = MapTileLayer()
layer.tileSize = 1024
layer.map = mapView
// Creates a marker in the center of the map.
let marker = GMSMarker()
marker.position = CLLocationCoordinate2D(latitude: 62.545144, longitude: 25.905153)
marker.title = "Marker"
marker.snippet = "Place"
marker.map = mapView
}
}
And the result looks like this both on device and simulator. With smaller tileSize the result is just more of smaller tiles but not covering the whole area.

Answer 1

Could not make Google Maps SDK work and moved to Apple MapKit. Got MapKit working according to example here: Advanced MapKit Tutorial: Custom Tiles. The only change that I needed to do to that example was to change order of lines as explained below (Xcode 11.4):
func setupTileRenderer() {
let overlay = AdventureMapOverlay()
overlay.canReplaceMapContent = true
mapView.add(overlay, level: .aboveLabels) // move this below next line
tileRenderer = MKTileOverlayRenderer(tileOverlay: overlay)
}
The change was that "mapView.addOverlay" line needs to come after "tileRenderer" line. The name of the method "mapView.add" had also changed to "mapView.addOverlay". Now works as expected.
I suspect that my initial problem with GoogleMaps SDK might have to do that I added those tiles in "Assets.xcassets" instead to normal folder as in the example mentioned above. I didn't test this as moved my code completely to use MapKit instead of GoogleMaps.