Question

我有一个简单的数组或MKAnnotations用于在视图加载时从CoreData获取的位置对象。当我删除位置对象时，我还手动从数组中删除位置对象。从数组中删除后，我调用removeAnnotations（），然后根据数组addAnnotations（）。我注意到MKAnnotationView不再位于删除的位置，但是它不会从MapView中移除，只能移动到0ºlat0ºlon。

我不确定我做错了什么才能让它从MapView中完全删除。

***注意：我正在学习教程，对于学习过程，我手动更新位置数组，而不是使用NSFetchedResultsController。

思想？

以下是代码：

var managedObjectContext: NSManagedObjectContext! {
    didSet {
        NSNotificationCenter.defaultCenter().addObserverForName(NSManagedObjectContextObjectsDidChangeNotification, object: managedObjectContext, queue: NSOperationQueue.mainQueue()) { notification in
            if self.isViewLoaded() {
                if let dictionary = notification.userInfo {

                    if dictionary["inserted"] != nil {

                        print("*** Inserted")
                        let insertedLocationSet: NSSet = dictionary["inserted"] as! NSSet
                        let insertedLocationArray: NSArray = insertedLocationSet.allObjects
                        let insertedLocation = insertedLocationArray[0] as! Location
                        self.locations.append(insertedLocation)

                    } else if dictionary["deleted"] != nil {

                        print("*** Deleted")
                        let deletedLocationSet = dictionary["deleted"] as! NSSet
                        let deletedLocationArray = deletedLocationSet.allObjects
                        let deletedLocation = deletedLocationArray[0] as! Location

                        if let objectIndexInLocations = self.locations.indexOf(deletedLocation) {

                            self.locations.removeAtIndex(objectIndexInLocations)

                        }

                    }
                }
            }

            self.drawAnnotations()

        }
    }
}

var locations = [Location]()


func updateLocations() {  // called by viewDidLoad()

    let entity = NSEntityDescription.entityForName("Location", inManagedObjectContext: managedObjectContext)

    let fetchRequest = NSFetchRequest()
    fetchRequest.entity = entity

    locations = try! managedObjectContext.executeFetchRequest(fetchRequest) as! [Location]

    drawAnnotations()

}

func drawAnnotations() {

    mapView.removeAnnotations(locations)
    mapView.addAnnotations(locations)

}

Answer 1

您的问题是，当您执行mapView.removeAnnotations(locations)时，locations数组已更新且已删除的注释不再位于该数组中，因此不会将其删除。您可以通过引用MapView本身的annotations属性来删除所有当前注释 -

func drawAnnotations() {
    mapView.removeAnnotations(mapView.annotations)
    mapView.addAnnotations(locations) 
}

MKAnnotationView无法从MKMapView中删除

1 个答案: