Question

我有以下UIViewController实现：

using System;
using System.Drawing;

using MonoTouch.Foundation;
using MonoTouch.UIKit;
using MonoTouch.MapKit;
using MonoTouch.CoreLocation;

namespace App.UI
{

    public partial class ProductsMapScreen : UIViewController
    {
        private MapDelegate mapDelegate;

        public ProductsMapScreen() : base("ProductsMapScreen", null)
        {
            TabBarItem = new UITabBarItem 
            { 
                Title = "Map", 
                Image = UIImage.FromFile("Images/tabmap.png")
            };
        }

        public Func<CLLocationCoordinate2D> GetCurrentLocation;

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            this.mapDelegate = new MapDelegate();
            this.mapView.Delegate = this.mapDelegate;

            SetVisibleRegion();
            AnnotateUsersCurrentLocation();

        }

        public override void ViewDidUnload()
        {
            base.ViewDidUnload();
            ReleaseDesignerOutlets();
        }

        public override bool ShouldAutorotateToInterfaceOrientation(UIInterfaceOrientation toInterfaceOrientation)
        {
            return (toInterfaceOrientation != UIInterfaceOrientation.PortraitUpsideDown);
        }

        private void AnnotateUsersCurrentLocation()
        {
            var location = GetCurrentLocation();
            this.mapView.AddAnnotation(new UserAnnotation(location));
        }

        private void SetVisibleRegion()
        {
            this.mapView.SetRegion(GetVisibleRegion(), true);
        }   

        private MKCoordinateRegion GetVisibleRegion()
        {
            var currentLocation = GetCurrentLocation();
            var span = new MKCoordinateSpan(0.2,0.2);
            var region = new MKCoordinateRegion(currentLocation,span);

            return region;
        }

        public class MapDelegate : MKMapViewDelegate 
        {
            public override MKAnnotationView GetViewForAnnotation(MKMapView mapView, NSObject annotation)
            {
                var userAnnotation = annotation as UserAnnotation;
                if(userAnnotation != null)
                    return getViewForUserAnnotation(mapView, userAnnotation);

                throw new Exception();
            }

            private MKAnnotationView getViewForUserAnnotation(MKMapView mapView, UserAnnotation annotation)
            {
                var annotationId = "userAnnotation";
                var annotationView = mapView.DequeueReusableAnnotation (annotationId) as MKPinAnnotationView;
                if (annotationView == null)
                    annotationView = new MKPinAnnotationView (annotation, annotationId);

                annotationView.PinColor = MKPinAnnotationColor.Green;
                annotationView.CanShowCallout = true;
                annotationView.Draggable = true;
                //annotationView.RightCalloutAccessoryView = UIButton.FromType (UIButtonType.DetailDisclosure);

                return annotationView;

            }
        }
    }
}

永远不会调用MapViewDelegate来解析我添加的单个注释的视图。我不知道为什么。

Answer 1

我有一个类似的问题 - 在我的情况下，我混淆了坐标（地球上的纬度/长点）和MKMapPoints（地图上的2d xy点）。我不确定你遇到的问题是否相同，但这是我要检查的第一件事。如果委托认为它不在地图的可见区域

，则不会被调用

你可以用MKMapPointForCoordinate＆amp; MKCoordinateForMapPoint

https://developer.apple.com/library/ios/#documentation/MapKit/Reference/MapKitDataTypesReference/Reference/reference.html

Answer 2

好的我不确定为什么MapDelegate类不起作用，但这个实现对我有用。我正在使用MT 5.2.2。

using System;
using System.Drawing;

using MonoTouch.Foundation;
using MonoTouch.UIKit;
using MonoTouch.MapKit;
using MonoTouch.CoreLocation;

namespace App.UI
{

    public partial class ProductsMapScreen : UIViewController
    {
        public Func<CLLocationCoordinate2D> GetCurrentLocation;

        public ProductsMapScreen() : base("ProductsMapScreen", null)
        {
            TabBarItem = new UITabBarItem 
            { 
                Title = "Map", 
                Image = UIImage.FromFile("Images/tabmap.png")
            };
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            this.mapView.GetViewForAnnotation += GetViewForAnnotation;
            SetVisibleRegion();
            AnnotateUsersCurrentLocation();
        }

        public override bool ShouldAutorotateToInterfaceOrientation(UIInterfaceOrientation toInterfaceOrientation)
        {
            return (toInterfaceOrientation != UIInterfaceOrientation.PortraitUpsideDown);
        }

        private void AnnotateUsersCurrentLocation()
        {
            var location = GetCurrentLocation();
            this.mapView.AddAnnotation(new[] {new UserAnnotation(location)});
        }

        private void SetVisibleRegion()
        {
            this.mapView.SetRegion(GetVisibleRegion(), true);
        }   

        private MKCoordinateRegion GetVisibleRegion()
        {
            var currentLocation = GetCurrentLocation();
            var span = new MKCoordinateSpan(0.2,0.2);
            var region = new MKCoordinateRegion(currentLocation,span);

            return region;
        }

        private MKAnnotationView GetViewForAnnotation(MKMapView mapView, NSObject annotation)
        {
            var userAnnotation = annotation as UserAnnotation;
            if(userAnnotation != null)
                return getViewForUserAnnotation(mapView, userAnnotation);

            throw new Exception();
        }

        private MKAnnotationView getViewForUserAnnotation(MKMapView mapView, UserAnnotation annotation)
        {
            var annotationId = "userAnnotation";
            var annotationView = mapView.DequeueReusableAnnotation (annotationId) as MKPinAnnotationView;
            if (annotationView == null)
                annotationView = new MKPinAnnotationView (annotation, annotationId);

            annotationView.PinColor = MKPinAnnotationColor.Green;
            annotationView.CanShowCallout = true;
            annotationView.Draggable = true;
            annotationView.RightCalloutAccessoryView = UIButton.FromType (UIButtonType.DetailDisclosure);

            return annotationView;

        }

    }
}

添加注释时不调用MKMapView MapViewDelegate

2 个答案: