android - defer rendering till surface is created (#16616)

src/Android/Avalonia.Android/AvaloniaActivity.cs

@@ -155,7 +155,7 @@ public class AvaloniaActivity : AppCompatActivity, IAvaloniaActivity
 
         base.OnDestroy();
     }
-        
+
     protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent? data)
     {
         base.OnActivityResult(requestCode, resultCode, data);

src/Android/Avalonia.Android/AvaloniaMainActivity.cs

@@ -21,8 +21,8 @@ public class AvaloniaMainActivity : AvaloniaActivity
         {
             initialContent ??= Lifetime.MainView; 
 
-            Lifetime.Activity = this;
             _view = new AvaloniaView(this) { Content = initialContent };
+            Lifetime.Activity = this;
         }
         else
         {

src/Android/Avalonia.Android/AvaloniaView.cs

@@ -21,6 +21,7 @@ namespace Avalonia.Android
         private readonly ViewImpl _view;
 
         private IDisposable? _timerSubscription;
+        private bool _surfaceCreated;
 
         public AvaloniaView(Context context) : base(context)
         {
@@ -32,6 +33,18 @@ namespace Avalonia.Android
 
             this.SetBackgroundColor(global::Android.Graphics.Color.Transparent);
             OnConfigurationChanged();
+
+            _view.InternalView.SurfaceWindowCreated += InternalView_SurfaceWindowCreated;
+        }
+
+        private void InternalView_SurfaceWindowCreated(object? sender, EventArgs e)
+        {
+            _surfaceCreated = true;
+
+            if (Visibility == ViewStates.Visible)
+            {
+                OnVisibilityChanged(true);
+            }
         }
 
         internal TopLevelImpl TopLevelImpl => _view;
@@ -43,9 +56,10 @@ namespace Avalonia.Android
             set { _root.Content = value; }
         }
 
-        protected override void Dispose(bool disposing)
+        internal new void Dispose()
         {
-            base.Dispose(disposing);
+            OnVisibilityChanged(false);
+            _surfaceCreated = false;
             _root?.Dispose();
             _root = null!;
         }
@@ -70,6 +84,8 @@ namespace Avalonia.Android
 
         internal void OnVisibilityChanged(bool isVisible)
         {
+            if (_root == null || !_surfaceCreated)
+                return;
             if (isVisible && _timerSubscription == null)
             {
                 if (AvaloniaLocator.Current.GetService<IRenderTimer>() is ChoreographerTimer timer)

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

@@ -13,9 +13,12 @@ namespace Avalonia.Android
     internal abstract class InvalidationAwareSurfaceView : SurfaceView, ISurfaceHolderCallback, INativePlatformHandleSurface
     {
         bool _invalidateQueued;
+        private bool _isDisposed;
         readonly object _lock = new object();
         private readonly Handler _handler;
 
+        internal event EventHandler? SurfaceWindowCreated;
+
         IntPtr IPlatformHandle.Handle => Holder?.Surface?.Handle is { } handle ?
             AndroidFramebuffer.ANativeWindow_fromSurface(JNIEnv.Handle, handle) :
             default;
@@ -39,7 +42,7 @@ namespace Avalonia.Android
                     return;
                 _handler.Post(() =>
                 {
-                    if (Holder?.Surface?.IsValid != true)
+                    if (_isDisposed || Holder?.Surface?.IsValid != true)
                         return;
                     try
                     {
@@ -53,6 +56,11 @@ namespace Avalonia.Android
             }
         }
 
+        internal new void Dispose()
+        {
+            _isDisposed = true;
+        }
+
         public void SurfaceChanged(ISurfaceHolder holder, Format format, int width, int height)
         {
             Log.Info("AVALONIA", "Surface Changed");
@@ -62,6 +70,7 @@ namespace Avalonia.Android
         public void SurfaceCreated(ISurfaceHolder holder)
         {
             Log.Info("AVALONIA", "Surface Created");
+            SurfaceWindowCreated?.Invoke(this, EventArgs.Empty);
             DoDraw();
         }