CODEWITHSUNDEEP
iosswiftgoogle-mapsgoogle-maps-markersswift4
Shubham Tomar
Shubham Tomar

Reputation: 293

swift 4 Google Map - how to update marker position using gesture.position

In viewDidLoad i added gesturerecognizers to mapView and also set true the consumeGestureInView and in the handleTap Method I convert the touch point into latLng and then set the marker position with latLng but the marker move slow very slow 

self.mapView.settings.consumesGesturesInView = true
for gestureRecognizer in self.mapView.gestureRecognizers! {
                                gestureRecognizer.addTarget(self, action: #selector(MapViewController.handleTap(_:)))
}

      @objc func handleTap(_ sender: UITapGestureRecognizer) {
                var allMarkers = markers
                if(sender.numberOfTouches == 1){
                    var positions = CGPoint()
                    var newPosition = CLLocationCoordinate2D()
                    let currentZoom = self.mapView.camera.zoom

                    switch (sender.state){
                    case .began:
                        positions = sender.location(in: self.mapView)
                        newPosition = self.mapView.projection.coordinate(for: positions)
                        let ind = self.getNearbymarkers(position: newPosition,markers:allMarkers)
                        allMarkers[ind].position = newPosition
                        self.mapView.settings.scrollGestures = false
                        mapView(self.mapView, didBeginDragging: allMarkers[ind])
                        self.mapView.settings.scrollGestures = true
                        break
                    case .ended:
                        positions = sender.location(in: self.mapView)
                        newPosition = self.mapView.projection.coordinate(for: positions)
                        let ind = self.getNearbymarkers(position: newPosition,markers:allMarkers)
                        print(ind)
                        allMarkers[ind].position = newPosition
                        self.mapView.settings.scrollGestures = false
                        mapView(self.mapView, didEndDragging: allMarkers[ind])
                        self.mapView.settings.scrollGestures = true
                        break
                    case .changed:
                        positions = sender.location(in: self.mapView)
                        newPosition = self.mapView.projection.coordinate(for: positions)
                        let ind = self.getNearbymarkers(position: newPosition,markers:allMarkers)
                        print(ind)
                        allMarkers[ind].position = newPosition
                        self.mapView.settings.scrollGestures = false
                        mapView(self.mapView, didDrag: allMarkers[ind])
                        self.mapView.settings.scrollGestures = true
                        break
                    default:
                        break
                    }
            }
        }

The issue is when this line execute then the marker rendered slow allMarkers[ind].position = newPosition like my finger move fast then the marker looks like moving behind the finger

Upvotes: 2

Views: 1975

Answers (1)

Vadim Popov
Vadim Popov

Reputation: 1217

As for my experience, there are no easy built-in solutions in GM framework for that. Unfortunately, the only interactive event that GMSMarker objects allow you to track (almost with no delays) is a simple tap, which triggers a corresponding callback in mapView's delegate. If you want something more complex, you have to implement stuff with your own custom marker view placed above map while performing drag&drop operation. Here is the algorithm:

1) Add a UIPanGestureRecognizer to the mapView. Set it's delegate to resolve conflicts with mapView's built-in gestureRecognizers.

2) When you start panning, in gestureRecognizerShouldBegin decide whether the user apply pan to map or to a marker. If to marker, allow panGR to fire (return true).

3) Hide GMSMarker object which you wish to move (set opacity to zero or just remove from map)

4) Insert your custom independent MarkerView (which visually duplicates the removed one at step 3) under the finger position

5) Move this custom view with the panGR's updates.

6) On finger release, replace your custom MarkerView with the GMSMarkerView on the final finger location in order to pin in to the map back.

Upvotes: 1

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