Request with Alamofire and Mapkit Swift 3

Question

I'm using Alamofire to request data from server, then use these data to show location on map. When panning or zooming map, it required to request API and reload the map.

The current issue is that whenever zooming or panning, CPU > 100% lead to the inability to zoom and pan.

My code is below:

Alamofire Request:

func getResultMap() {
    DispatchQueue.main.async( execute: {
        self.skipSearchRequest = true

        SearchWebservice.sharedInstance.getResultMap(currentSearchObject, success: { (result) in
            var clusters: [Cluster] = []
            var markers : [Marker] = []
            if self.mapLayerType == .ClusterOverview {
                for item in result.clusterOverview {
                    clusters.append(item)
                }
                self.setMapAnnotations(annotations: clusters)
            } else {
                for item in result.markers {
                    markers.append(item)
                }
                self.addMapAnnotations(annotations: markers)
            }
            self.skipSearchRequest = false
        }) { (error) in
            print(error)
        }
    })
}

Add/Remove Annotation:

 func addMapAnnotations(annotations: [MKAnnotation]) {
    var annotationsToRemove :[MKAnnotation] = []
    var annotationsToAdd: [MKAnnotation] = annotations
    let annotationsTemp: [MKAnnotation] = annotations

    for item in mapView.annotations {
        if item.isKind(of: Cluster.self) {
            annotationsToRemove.append(item)
        } else if item.isKind(of: Marker.self) {
            for itemTemp in annotationsTemp {
                if itemTemp.coordinate.latitude == item.coordinate.longitude && itemTemp.coordinate.longitude == item.coordinate.longitude {
                    annotationsToAdd.remove(at: annotationsToAdd.index(where: {$0.coordinate.latitude == itemTemp.coordinate.latitude && $0.coordinate.longitude == itemTemp.coordinate.longitude})!)
                }
            }
        }
    }
    mapView.removeAnnotations(annotationsToRemove)
    mapView.addAnnotations(annotationsToAdd)
}

func setMapAnnotations(annotations: [MKAnnotation]) {
    self.mapView.removeAnnotations(self.mapView.annotations)
    var annotationsToAdd: [MKAnnotation] = []
    for item in annotations {
        if item.isKind(of: Cluster.self) {
            annotationsToAdd.append(item)
        } else if item.isKind(of: Marker.self) {
            annotationsToAdd.append(item)
        }
    }
    DispatchQueue.main.async {
         self.mapView.addAnnotations(annotationsToAdd)
    }
}

Map delegate:

func mapView(_ mapView: MKMapView, regionDidChangeAnimated animated: Bool) {
    if !skipSearchRequest {
            Timer.scheduledTimer(timeInterval: 0.7, target: self, selector: #selector(COHFResultMapViewController.getResultMap), userInfo: nil, repeats: false)
    } else {
        skipSearchRequest = false
    }

}

func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
    if annotation.isKind(of: Cluster.self) {
        let reuseId = "Cluster"
        var clusterView = mapView.dequeueReusableAnnotationView(withIdentifier: reuseId) as? ClusterView
        if clusterView == nil {
            clusterView = ClusterView(annotation: annotation, reuseIdentifier: reuseId)
        } else {
            clusterView?.annotation = annotation
        }
        return clusterView
    } else {
        let reuseId = "Pin"
        var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: reuseId)

        if annotationView == nil {
            annotationView = AnnotationView(annotation: annotation, reuseIdentifier: reuseId)
        } else {
            annotationView?.annotation = annotation
        }
        return annotationView
    }
}

How to improve performance and best practice for reloading annotation in Mapkit?

Xcode console debugging output

@NhatDinh In lifetime debugging, CPU > 100% and high memory. https://i.stack.imgur.com/tDpIo.png — Manh N., Feb 03 '17 at 03:18
Hint: You can use profiler instruments to find memory leak in your code! — Nhat Dinh, Feb 03 '17 at 03:22

score 0 · Answer 1 · answered Feb 03 '17 at 05:08

You are doing the API request on the main thread, a no-no.

You need to run the API request on a background thread, then update the map on the main thread. Like so:

DispatchQueue.global(qos: .userInitiated).async {
    SearchWebservice.sharedInstance.getResultMap(currentSearchObject, success: { (result) in

        //process the results

        //make sure to do any UI/Map stuff back on the main thread
        DispatchQueue.main.async(execute: { [unowned self] in
            self.mapView.addAnnotation(marker)
        })

    }
}

Request with Alamofire and Mapkit Swift 3

1 Answers1