Question

我有几个问题应该是一个非常简单的代码。目标是从数据库中读取项目并将其作为地图中的引脚。如果该项目已标记为收藏，则该引脚应为不同的颜色。

第一个问题是并非所有项目都被渲染。在示例中，我将使用从查询返回的12个结果，并且我已经验证每个项目都创建了MKAnnotation，并且每个注释都会调用ViewFor。

除了不显示所有引脚外，还有另外两个问题。

滚动地图时，第一针会随机丢失标题。

第二个最喜欢的（绿色）很少呈现绿色。 80％的时间以标准蓝色出现。我再一次确认MKMarkerAnnotationView颜色设置正确。

由于所有这些问题，我不得不得出结论，我做的事情从根本上说是非常错误的。这很奇怪，因为这似乎很简单。

class FacilityMarker: NSObject, MKAnnotation {

// title and subtitle are from the MKAnnotation protocol
var coordinate:     CLLocationCoordinate2D
var title:          String?
var address:        String
var phone:          String
var providerNumber: String
var favorite:       Bool
var subtitle:       String? {
    get {
        return phone
    }
}

查看控制器

    class MapViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {

@IBOutlet weak var mapView: MKMapView!

override func viewDidLoad() {
    super.viewDidLoad()
    mapView.delegate = self
    mapView.showAnnotations(mapView.annotations, animated: true)


// Create Annotations for all the facilities that are now visible on map
func mapView(_ mapView: MKMapView, regionDidChangeAnimated animated: Bool) {
    let edgePoints = mapView.edgePoints()

    let minLat = edgePoints.ne.latitude < edgePoints.sw.latitude ? edgePoints.ne.latitude : edgePoints.sw.latitude
    let maxLat = edgePoints.ne.latitude > edgePoints.sw.latitude ? edgePoints.ne.latitude : edgePoints.sw.latitude
    let minLong = edgePoints.ne.longitude < edgePoints.sw.longitude ? edgePoints.ne.longitude : edgePoints.sw.longitude
    let maxLong = edgePoints.ne.longitude > edgePoints.sw.longitude ? edgePoints.ne.longitude : edgePoints.sw.longitude
    let visibleCitiesReqeuest =
        managedObjectModel.fetchRequestFromTemplate(withName: "FetchByCoordinates", substitutionVariables: ["minLat" : minLat, "minLong" : minLong, "maxLat" : maxLat, "maxLong" : maxLong])
    do {
        let facilities = try CoreDataHelper.shared.persistentContainer.viewContext.fetch(visibleCitiesReqeuest!) as! [FacilityMO]
       for facility in facilities {
            let facilityMarker = FacilityMarker(name: facility.facilityName!, address: facility.addressLine1!, location: facility.location!, phone: facility.phoneNumber!, providerNumber: facility.providerNumber!, favorite: facility.favorite)   
            mapView.addAnnotation(facilityMarker)
        }
    } catch {
        let alertController = UIAlertController(title: "No Facilities", message: "There are no Facilities within the visible map area", preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.cancel, handler: nil))
        self.present(alertController, animated: true, completion: nil)
    }
}

// Put the pins in the map
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
    guard let annotation = annotation as? FacilityMarker else { return nil}

    let identifier = "facility"
    var view: MKMarkerAnnotationView
    if let dequeuedView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier) as?
        MKMarkerAnnotationView {
        dequeuedView.annotation = annotation
        view = dequeuedView
    } else {
        print("CREATING NEW View for: \(annotation.title!)")
        view = MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: identifier)
    }

    // Set the Colors
    if (annotation.favorite) {
        view.markerTintColor = .green
        view.tintColor = .green
    } else {
        view.markerTintColor = .blue
        view.tintColor = .blue
    }
    return view
}

这是查询返回的实际数据。仅渲染突出显示的项目。这在所有测试中都是100％一致的。

创建新视图：SEMINOLE DIALYSIS CENTER
创建新视图：LAKE SEMINOLE DIALYSIS
创建新视图：RAI CARE CENTERS - LARGO
创建新视图：BAY BREEZE DIALYSIS CLINIC INC
创建新视图：RENVIVA DIALYSIS CENTER OF CLEARWATER，LLC
创建新视图：FKC - BELLEAIR DIALYSIS CENTER
创建新视图：RAI CARE CENTERS - CLEARWATER
创建新视图：FMC - BELLEAIR HOME THERAPIES
创建新视图：CORVA GULF COAST DIALYSIS CENTER
创建新视图：GULF BREEZE DIALYSIS CENTER
为：BMA - CLEARWATER创建新视图
创建新视图：RAI-US 19 NORTH-CLEARWATER

以下是显示上述结果的捕获

这是一个初始渲染。这次BMA引脚为蓝色，设置为绿色。

滚动此时间后，BMA色调正确。什么时候是正确的，没有模式。

更多滚动，只是添加更多陌生感，有时一个或多个注释不会呈现其标题属性

请求调试的输出：

RAI CARE CENTERS - LARGO是蓝色的
BMA - CLEARWATER是绿色
RENVIVA CLEALWATER DIALYSIS CENTER，LLC是蓝色
RAI CARE CENTERS - CLEARWATER是蓝色
FKC - BELLEAIR DIALYSIS CENTER是蓝色的
FMC - BELLEAIR HOME THERAPIES是蓝色的
GULF BREEZE DIALYSIS CENTER是蓝色的
BAY BREEZE DIALYSIS CLINIC INC是蓝色的
RAI-US 19 NORTH-CLEARWATER是蓝色的
CORVA GULF COAST DIALYSIS CENTER为蓝色

Answer 1

尝试以下调试代码。你能显示输出吗？

    ...
    // Set the Colors
    if (annotation.favorite) {
        print(annotation.title, "is green")
        view.markerTintColor = .green
        view.tintColor = .green
    } else {
        print(annotation.title, "is blue")
        view.markerTintColor = .blue
        view.tintColor = .blue
    }
    ...

地图注释的许多问题

1 个答案: