Can't run Xamarin project after installing SkiaSharp?

Question

I installed SkiaSharp and SkiaSharp.Views.Forms and when I used them in my code:

public MainPage()
        {
            InitializeComponent();

            SKCanvasView canvasView = new SKCanvasView();
            canvasView.PaintSurface += OnCanvasViewPaintSurface;
            Content = canvasView;

        }


void OnCanvasViewPaintSurface(object sender, SKPaintSurfaceEventArgs args)
    {
        SKImageInfo info = args.Info;
        SKSurface surface = args.Surface;
        SKCanvas canvas = surface.Canvas;

        canvas.Clear();

        SKPaint paint = new SKPaint
        {
            Style = SKPaintStyle.Stroke,
            Color = Color.Red.ToSKColor(),
            StrokeWidth = 25
        };
        canvas.DrawCircle(info.Width / 2, info.Height / 2, 100, paint);

        paint.Style = SKPaintStyle.Fill;
        paint.Color = SKColors.Blue;
        canvas.DrawCircle(info.Width / 2, info.Height / 2, 100, paint);
    }

The project can't run, (the orange color of the debugging mode just disappear immediately), and there're no errors.

when I commented out the code above, the project run normally! I'm using Visual Studio 2017 version 15.4.5

I tried opening the project in VS 2015, I got this exception in MainActivity of the Android project at:

LoadApplication(new App());

Message:

Specified cast is not valid.

StackTrace:

System.InvalidCastException: Specified cast is not valid. at (wrapper castclass) System.Object:__castclass_with_cache (object,intptr,intptr) at Xamarin.Forms.Internals.Registrar1[TRegistrable].GetHandler (System.Type type) [0x0001b] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Registrar.cs:37 at Xamarin.Forms.Internals.Registrar1[TRegistrable].GetHandler[TOut] (System.Type type) [0x00000] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Core\Registrar.cs:42 at Xamarin.Forms.Platform.Android.Platform.CreateRenderer (Xamarin.Forms.VisualElement element) [0x00006] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\Platform.cs:284 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:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:86 at Xamarin.Forms.Platform.Android.VisualElementPackager.SetElement (Xamarin.Forms.VisualElement oldElement, Xamarin.Forms.VisualElement newElement) [0x00104] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:219 at Xamarin.Forms.Platform.Android.VisualElementPackager.Load () [0x00000] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementPackager.cs:70 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetPackager (Xamarin.Forms.Platform.Android.VisualElementPackager packager) [0x00007] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:371 at Xamarin.Forms.Platform.Android.VisualElementRenderer1[TElement].SetElement (TElement element) [0x000ce] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:174 at Xamarin.Forms.Platform.Android.VisualElementRenderer`1[TElement].Xamarin.Forms.Platform.Android.IVisualElementRenderer.SetElement (Xamarin.Forms.VisualElement element) [0x00027] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\VisualElementRenderer.cs:120 at Xamarin.Forms.Platform.Android.Platform.CreateRenderer (Xamarin.Forms.VisualElement element) [0x0001f] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\Platform.cs:285 at Xamarin.Forms.Platform.Android.AppCompat.Platform.AddChild (Xamarin.Forms.Page page, System.Boolean layout) [0x00015] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\Platform.cs:268 at Xamarin.Forms.Platform.Android.AppCompat.Platform.SetPage (Xamarin.Forms.Page newRoot) [0x0007a] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\Platform.cs:245 at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.InternalSetPage (Xamarin.Forms.Page page) [0x0009b] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:337 at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.SetMainPage () [0x00000] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:407 at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.LoadApplication (Xamarin.Forms.Application application) [0x00229] in C:\BuildAgent3\work\ca3766cfc22354a1\Xamarin.Forms.Platform.Android\AppCompat\FormsAppCompatActivity.cs:152 at XamApp.Droid.MainActivity.OnCreate (Android.OS.Bundle bundle) [0x00028] in D :\P\XamApp\XamApp\XamApp.Android\MainActivity.cs:25

mshwf mshwf · Accepted Answer · 2017-12-06T17:20:15

To work, I have to install SkiaSharp, SkiaSharp.Views, and SkiaSharp.Views.Forms via nuget to the Android and iOS projects, PCL only requires SkiaSharp and SkiaSharp.Views.Forms.

original answer here: https://forums.xamarin.com/discussion/comment/310695/#Comment_310695

Can't run Xamarin project after installing SkiaSharp?

1 Answers