为了使一切顺利和优雅,我将首先实例化MKMapView,启动CLLocationManager并等待,直到我得到一个doUpdateLocations.然后我会尝试从一个数据库获取我的数据与完成处理程序.

我是不是该

a)立即获取所有数据

b)以小块或块获取数据？

最好的方法是什么？

func locationManager(manager: CLLocationManager,didUpdateLocations locations: [CLLocation]) {
    self.gotoCurrentLocation()
    if let userLocation = manager.location {
        GroundHelper.getAllGroundLocations(userLocation) { self.handleWaypoints($0!) }
    }
}

private func handleWaypoints(grounds: [Ground]) {
    mapView.addAnnotations(grounds)
}

// MARK: - Helper Methods

typealias GPXCompletionHandler = ([Ground]?) -> Void

class func getAllGroundLocations(userlocation: CLLocation,completionHandler: GPXCompletionHandler)  {

    let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT
    dispatch_async(dispatch_get_global_queue(priority,0),{ ()->() in
        var results = RestApiManager.sharedInstance.getGPS(userlocation,limit: 50)

        // return first 50 results
        dispatch_async(dispatch_get_main_queue(),{

            var grounds = [Ground]()
            for result in results {
                let (_,jsonGround) = result
                let ground = Ground(json:jsonGround)
                grounds.append(ground)
            }
            completionHandler(grounds)
        })

        // get the rest
        results = RestApiManager.sharedInstance.getGPS(userlocation)

        // return them
        dispatch_async(dispatch_get_main_queue(),jsonGround) = result
                let ground = Ground(json:jsonGround)
                grounds.append(ground)
            }
            completionHandler(grounds)

        })
    })
}