我尝试将2D视图转换为3D视图，一旦达到PCL项目的定义缩放级别MAP 3D Project - Github
所以，wat我做了（在PCL部分），我创建了一个 customMap.cs 一个对象，它基本上是一个继承自Xamarin.Forms.Map的对象：public class CustomMap : Map
public class CustomMap : Map
{
/// <summary>
/// Just for my test since I can't find the way to find the current location of the camera
/// </summary>
public static readonly BindableProperty LocationProperty =
BindableProperty.Create(nameof(Location), typeof(Position), typeof(CustomMap), new Position(47.942660, 0.261979));
/// <summary>
/// Assessor for Location property.
/// </summary>
public Position Location
{
get { return (Position)GetValue(LocationProperty); }
set { SetValue(LocationProperty, value); }
}
/// <summary>
/// Just for my test since I can't find the way to get the current zoom level
/// </summary>
public static readonly BindableProperty ZoomLevelProperty =
BindableProperty.Create(nameof(ZoomLevel), typeof(Distance), typeof(CustomMap), new Distance());
/// <summary>
/// Assessor for ZoomLevel property.
/// </summary>
public Distance ZoomLevel
{
get { return (Distance)GetValue(ZoomLevelProperty); }
set { SetValue(ZoomLevelProperty, value); }
}
#region Constructor
public CustomMap()
{
this.PropertyChanged += (object sender, PropertyChangedEventArgs e) =>
{
CustomMap map = sender as CustomMap;
if (map.VisibleRegion != null)
{
this.ZoomLevel = map.VisibleRegion.Radius;
}
};
isMapLoaded = false;
}
#endregion
#region Additionnals
private bool isMapLoaded;
/// <summary>
/// Method called from the renderer once the map is loaded
/// </summary>
public void MapLoaded()
{
isMapLoaded = true;
if (this.VisibleRegion != null)
{
this.ZoomLevel = this.VisibleRegion.Radius;
}
}
public bool IsMapLoaded { get { return (isMapLoaded); } }
#endregion
}
所以现在，在渲染器部分，如果我们看一下UWP（我有一台Windows机器，所以它使我的构建/测试更容易/更快在本地x86上运行），我做了一个基本的渲染器：{{ 1}}
public class CustomMapRenderer : MapRenderer现在，我面临两个问题/问题。首先，我有一个例外，/// <summary>
/// CustomRenderer for the CustomMap created in the PCL part.
/// This Renderer gives us the possibility to add/override some functionalities.
/// </summary>
public class CustomMapRenderer : MapRenderer
{
/// <summary>
/// Instance of the native map for this plateform.
/// </summary>
MapControl nativeMap;
/// <summary>
/// Instance of our Custom control declared in the PCL part.
/// </summary>
CustomMap customMap;
/// <summary>
/// We override the OnElementChanged() event handler to get the desired instance. We also use it for updates.
/// </summary>
/// <param name="e">It contains either the NewElement or the OldElement</param>
protected override void OnElementChanged(ElementChangedEventArgs<Map> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
customMap = (CustomMap)e.NewElement;
nativeMap = Control as MapControl;
nativeMap.Loaded += ((sender, re) =>
{
customMap.MapLoaded();
});
}
}
/// <summary>
/// The on element property changed callback.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="PropertyChangedEventArgs"/>Instance containing the event data.</param>
protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (this.customMap == null || this.nativeMap == null)
return;
if (e.PropertyName == CustomMap.ZoomLevelProperty.PropertyName)
UpdateCameraView();
}
private async void UpdateCameraView()
{
if (customMap == null || nativeMap == null)
return;
if (nativeMap.Is3DSupported && customMap.IsMapLoaded)
{
try
{
// Set the aerial 3D view.
nativeMap.Style = MapStyle.Aerial3DWithRoads;
// Specify the location.
BasicGeoposition hwGeoposition = new BasicGeoposition() { Latitude = customMap.VisibleRegion.LatitudeDegrees, Longitude = customMap.VisibleRegion.LongitudeDegrees };
Geopoint hwPoint = new Geopoint(hwGeoposition);
// Create the map scene.
MapScene hwScene = MapScene.CreateFromLocationAndRadius(hwPoint,
80, //show this many meters around
0, //looking at it to the North
60); //degrees pitch
// Set the 3D view with animation.
await nativeMap.TrySetSceneAsync(hwScene, MapAnimationKind.Bow);
} catch (Exception e)
{
Debug.WriteLine("------------------------");
Debug.WriteLine(e.ToString());
Debug.WriteLine(e.StackTrace);
Debug.WriteLine("------------------------");
}
}
else
{
// If 3D views are not supported, display dialog.
ContentDialog viewNotSupportedDialog = new ContentDialog()
{
Title = "3D is not supported",
Content = "\n3D views are not supported on this device.",
PrimaryButtonText = "OK"
};
await viewNotSupportedDialog.ShowAsync();
}
}
}
==＆gt;中的try {}无法捕获。 private async void UpdateCameraView()我在互联网上搜索，它说我正在访问一个空值，这是真的可能，因为我检查了值+我检查了一个断点，一切似乎初始化..
另外，如果我无法访问当前的相机区域位置值，如何管理从2D到3D的转换（当达到x米/英里的缩放时）？因为，引用Display maps with 2D, 3D, and Streetside views documentation，我需要The program '[17780] Map3DProject.UWP.exe' has exited with code -1073741819 (0xc0000005) 'Access violation'.来创建一个半径为的场景。
在本文档中，我看到您也可以拨打Geopoint，但我无法应用任何轮换价值。所以，对我来说无用
如果有人对我的问题的逻辑或答案有任何建议，欢迎发表评论！
感谢，
最高