SkiaSharp 无效转换异常

Question

在 LoadApplication(new App()); 中收到 InvalidCastException。我在 PCL 和 Android 中添加了 SkiaSharp 和 SkiaSharp.Views.Forms。它还自动将 SkiaSharp.Views 包添加到 Android 项目。

我删除了所有复杂代码并将这部分留在我的 XAML 文件中

<ContentView 
    xmlns="http://xamarin.com/schemas/2014/forms" 
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:skia="clr-namespace:SkiaSharp.Views.Forms;assembly=SkiaSharp.Views.Forms"     
    x:Class="SkiaSharpRemote.MediaControlView">
    <ContentView.Content>
        <!--<skia:SKCanvasView
            x:Name="canvas"
            VerticalOptions="Fill"
            HorizontalOptions="Fill"
            PaintSurface="Canvas_PaintSurface">
        </skia:SKCanvasView>-->
    </ContentView.Content>
</ContentView>

我注释掉 skCanvasView 行后应用程序加载。如果我取消注释，则会抛出以下异常。

at (wrapper castclass) System.Object:__castclass_with_cache (object,intptr,intptr) at Xamarin.Forms.Registrar1[TRegistrable].GetHandler (System.Type type) [0x0001b] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Core\Registrar.cs:24 at Xamarin.Forms.Registrar1[TRegistrable].GetHandler[TOut] (System.Type type) [0x00000] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Core\Registrar.cs:29 at Xamarin.Forms.Platform.Android.Platform.CreateRenderer (Xamarin.Forms.VisualElement element) [0x00006] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\Platform.cs:288 at Xamarin.Forms.Platform.Android.VisualElementPackager.AddChild (Xamarin.Forms.VisualElement view, Xamarin.Forms.Platform.Android.IVisualElementRenderer oldRenderer, Xamarin.Forms.Platform.Android.RendererPool pool, System.Boolean sameChildren) [0x00023] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:74 at Xamarin.Forms.Platform.Android.VisualElementPackager.SetElement (Xamarin.Forms.VisualElement oldElement, Xamarin.Forms.VisualElement newElement) [0x00104] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:207 at Xamarin.Forms.Platform.Android.VisualElementPackager.Load () [0x00000] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:58 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetPackager (Xamarin.Forms.Platform.Android.VisualElementPackager packager) [0x00007] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:337 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetElement (TElement element) [0x00111] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:196 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].Xamarin.Forms.Platform.Android.IVisualElementRenderer.SetElement (Xamarin.Forms.VisualElement element) [0x00027] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:129 at Xamarin.Forms.Platform.Android.Platform.CreateRenderer (Xamarin.Forms.VisualElement element) [0x0001f] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\Platform.cs:289 at Xamarin.Forms.Platform.Android.VisualElementPackager.AddChild (Xamarin.Forms.VisualElement view, Xamarin.Forms.Platform.Android.IVisualElementRenderer oldRenderer, Xamarin.Forms.Platform.Android.RendererPool pool, System.Boolean sameChildren) [0x00023] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:74 at Xamarin.Forms.Platform.Android.VisualElementPackager.SetElement (Xamarin.Forms.VisualElement oldElement, Xamarin.Forms.VisualElement newElement) [0x00104] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:207 at Xamarin.Forms.Platform.Android.VisualElementPackager.Load () [0x00000] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:58 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetPackager (Xamarin.Forms.Platform.Android.VisualElementPackager packager) [0x00007] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:337 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetElement (TElement element) [0x00111] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:196 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].Xamarin.Forms.Platform.Android.IVisualElementRenderer.SetElement (Xamarin.Forms.VisualElement element) [0x00027] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:129 at Xamarin.Forms.Platform.Android.Platform.CreateRenderer (Xamarin.Forms.VisualElement element) [0x0001f] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\Platform.cs:289 at Xamarin.Forms.Platform.Android.VisualElementPackager.AddChild (Xamarin.Forms.VisualElement view, Xamarin.Forms.Platform.Android.IVisualElementRenderer oldRenderer, Xamarin.Forms.Platform.Android.RendererPool pool, System.Boolean sameChildren) [0x00023] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:74 at Xamarin.Forms.Platform.Android.VisualElementPackager.SetElement (Xamarin.Forms.VisualElement oldElement, Xamarin.Forms.VisualElement newElement) [0x00104] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:207 at Xamarin.Forms.Platform.Android.VisualElementPackager.Load () [0x00000] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:58 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetPackager (Xamarin.Forms.Platform.Android.VisualElementPackager packager) [0x00007] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:337 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetElement (TElement element) [0x00111] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:196 at Xamarin.Forms.Platform.Android.VisualElementRenderer`1[TElement].Xamarin.Forms.Platform.Android.IVisualElementRenderer.SetElement (Xamarin.Forms.VisualElement element) [0x00027] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:129 at Xamarin.Forms.Platform.Android.Platform.CreateRenderer (Xamarin.Forms.VisualElement element) [0x0001f] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\Platform.cs:289 at Xamarin.Forms.Platform.Android.AppCompat.Platform.AddChild (Xamarin.Forms.Page page, System.Boolean layout) [0x00015] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\Platform.cs:250 at Xamarin.Forms.Platform.Android.AppCompat.Platform.SetPage (Xamarin.Forms.Page newRoot) [0x00089] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\Platform.cs:239 at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.InternalSetPage (Xamarin.Forms.Page page) [0x0009b] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:374 at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.SetMainPage () [0x00000] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:444 at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.LoadApplication (Xamarin.Forms.Application application) [0x00183] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:135 at SkiaSharpRemote.Droid.MainActivity.OnCreate (Android.OS.Bundle bundle) [0x0002e] in /Users/simonlam/Desktop/Samples/Xamarin/SkiaRemote/SkiaSharpRemote/Droid/MainActivity.cs:25 at Android.Support.V4.App.FragmentActivity.n_OnCreate_Landroid_os_Bundle_ (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_savedInstanceState) [0x00011] in <27c17fe440cf491ba8255bcefade6e02>:0 at (wrapper dynamic-method) System.Object:a050e315-9322-4894-b9ce-8db88ad775ab (intptr,intptr,intptr)

这个错误并没有告诉我太多，我只看到这是某种转换错误。

我还有另一个项目也使用了 skiasharp。我基本上遵循相同的路线但是对于这个项目它没有用。

Answer 1

执行以下操作：

将 SkiaSharp.Views.Forms NuGet 添加到所有项目！（PCL/Shared， Android 和 iOS 项目。）
然后清理并重建您的解决方案。

这将解决您的问题。

SkiaSharp 无效转换异常

SkiaSharp Invalid Cast Exception

xamarin

xamarin.android

xamarin.forms

skiasharp