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如何从Firebase获取单个数据库引用

core-location firebase google-maps swift ios

Naveen Saini · 技术社区 · 7 年前

这会在我的自定义标记图像文件上产生奇怪的效果。

var posts=[postStruct]()
var mapView : GMSMapView? = nil
var friendLocator : [Locator] = [Locator]() 

struct Locator {
    let name: String
    let long: CLLocationDegrees
    let lat: CLLocationDegrees
}

var latPass: Double!
var longPass: Double!
var fetchLat: Double!
var fetchLong: Double!

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{
    var location=locations[0]
    let span:MKCoordinateSpan=MKCoordinateSpanMake(0.01, 0.01)
    var myLocation:CLLocationCoordinate2D=CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)
    let region:MKCoordinateRegion=MKCoordinateRegionMake(myLocation, span)
    latPass=28.3217378
    longPass=75.6895935

    post()
    self.configureMapView()

    let dataBaseRef=FIRDatabase.database().reference()
    dataBaseRef.child("Raunak Trikha").queryOrderedByKey().observeSingleEvent(of: .childAdded, with: {(snapshot) in

        let postDict = snapshot.value as? [String : AnyObject] ?? [:]
        var fetchLat = postDict["lat"] as! Double
        var fetchLong = postDict["long"] as! Double

        let locator = Locator(name: "Raunak Trikha", long: fetchLong, lat: fetchLat)
        self.friendLocator.append(locator)
        self.locateFriend()
        print(fetchLat)
        print(fetchLong)
    })       
    manager.stopUpdatingLocation()

    self.view = mapView

}

func locateFriend() {
    for friend in friendLocator{
        let friendMarker = GMSMarker()
        friendMarker.position=CLLocationCoordinate2D(latitude: friend.lat, longitude: friend.long)
        friendMarker.title=friend.name
        friendMarker.map=mapView
        mapView?.selectedMarker=friendMarker
        if friend.name=="Virat Singh"{

            friendMarker.icon=UIImage(named: "ViratPin.png")
        }

        else if friend.name=="Raunak Trikha"{

            friendMarker.icon=UIImage(named: "currentLocation.png")
        }
    }
    do {
        mapView?.mapStyle = try GMSMapStyle(jsonString: kMapStyle)
    } catch {
        NSLog("One or more of the map styles failed to load. \(error)")
    }
}


func configureMapView(){
    let camera = GMSCameraPosition.camera(withLatitude: latPass, longitude: longPass, zoom: 10)
    self.mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)
    view = mapView
    mapView?.settings.scrollGestures = true
    mapView?.settings.zoomGestures = true
    mapView?.settings.myLocationButton = true
    //mapView?.addSubview(searchBar)
    //mapView?.addSubview(searchSupporter)
    //mapView?.bringSubview(toFront: searchBar)

    for gesture in (mapView?.gestureRecognizers!)! {

        mapView?.removeGestureRecognizer(gesture)

    }

}

当我打印时 fetchLat & fetchLong 我得到相同的坐标4次,这重叠了我的自定义标记图像,创造了奇怪的效果。

2 回复 | 直到 7 年前

NSGangster 7 年前

由于您的代码添加了特定的 Locator 多次调用struct,请检查数组,确保它不包含完全相同的struct,然后将其本地添加到数组中。

name 结构的属性是每个结构的唯一标识符,这可能不是您的情况。您也可以比较 filter lat long .

    let locator = Locator(name: "Raunak Trikha", long: fetchLong, lat: fetchLat)
    if self.friendLocator.filter({ $0.name == locator.name }).count == 0 {
       self.friendLocator.append(locator)  
    }
    self.locateFriend()

Alex McPherson 7 年前

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 只要您的位置发生变化/更新,或GPS定位(预热)到您的位置,就会收到呼叫。

observeSingleEvent() 然而,这是正确的,因为您已经在上面的didUpdateLocations函数中定义了调用,它将被多次调用。