fix crash when accessing clipbord on android

src/Android/Avalonia.Android/AndroidPlatform.cs

@@ -38,7 +38,7 @@ namespace Avalonia.Android
             Options = AvaloniaLocator.Current.GetService<AndroidPlatformOptions>() ?? new AndroidPlatformOptions();
 
             AvaloniaLocator.CurrentMutable
-                .Bind<IClipboard>().ToTransient<ClipboardImpl>()
+                .Bind<IClipboard>().ToConstant(new ClipboardImpl())
                 .Bind<ICursorFactory>().ToTransient<CursorFactory>()
                 .Bind<IWindowingPlatform>().ToConstant(new WindowingPlatformStub())
                 .Bind<IKeyboardDevice>().ToSingleton<AndroidKeyboardDevice>()

src/Android/Avalonia.Android/Platform/ClipboardImpl.cs

@@ -2,32 +2,26 @@ using System;
 using System.Threading.Tasks;
 
 using Android.Content;
-using Android.Runtime;
-using Android.Views;
 
 using Avalonia.Input;
 using Avalonia.Input.Platform;
-using Avalonia.Platform;
 
 namespace Avalonia.Android.Platform
 {
     internal class ClipboardImpl : IClipboard
     {
-        private Context context = (AvaloniaLocator.Current.GetService<IWindowImpl>() as View).Context;
+        private ClipboardManager? _clipboardManager;
 
-        private ClipboardManager ClipboardManager
+        internal void SetClipboardManager(ClipboardManager? value)
         {
-            get
-            {
-                return this.context.GetSystemService(Context.ClipboardService).JavaCast<ClipboardManager>();
-            }
+            _clipboardManager = value;
         }
 
         public Task<string> GetTextAsync()
         {
-            if (ClipboardManager.HasPrimaryClip)
+            if (_clipboardManager?.HasPrimaryClip == true)
             {
-                return Task.FromResult<string>(ClipboardManager.PrimaryClip.GetItemAt(0).Text);
+                return Task.FromResult<string>(_clipboardManager.PrimaryClip.GetItemAt(0).Text);
             }
 
             return Task.FromResult<string>(null);
@@ -35,15 +29,25 @@ namespace Avalonia.Android.Platform
 
         public Task SetTextAsync(string text)
         {
+            if(_clipboardManager == null)
+            {
+                return Task.CompletedTask;
+            }
+
             ClipData clip = ClipData.NewPlainText("text", text);
-            ClipboardManager.PrimaryClip = clip;
+            _clipboardManager.PrimaryClip = clip;
 
             return Task.FromResult<object>(null);
         }
 
         public Task ClearAsync()
         {
-            ClipboardManager.PrimaryClip = null;
+            if (_clipboardManager == null)
+            {
+                return Task.CompletedTask;
+            }
+
+            _clipboardManager.PrimaryClip = null;
 
             return Task.FromResult<object>(null);
         }

src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs

@@ -29,6 +29,8 @@ using Window = Android.Views.Window;
 using Android.Graphics.Drawables;
 using Android.OS;
 using Android.Text;
+using Avalonia.Input.Platform;
+using ClipboardManager = Android.Content.ClipboardManager;
 
 namespace Avalonia.Android.Platform.SkiaPlatform
 {
@@ -55,6 +57,9 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             _gl = new EglGlPlatformSurface(this);
             _framebuffer = new FramebufferManager(this);
 
+            (AvaloniaLocator.Current.GetRequiredService<IClipboard>() as ClipboardImpl)?
+                .SetClipboardManager(avaloniaView.Context?.GetSystemService(Context.ClipboardService).JavaCast<ClipboardManager>());
+
             RenderScaling = _view.Scaling;
 
             MaxClientSize = new PixelSize(_view.Resources.DisplayMetrics.WidthPixels,