Don't build surface until the platform view has been created (#101399)

packages/flutter/lib/src/rendering/platform_view.dart

@@ -176,7 +176,12 @@ class RenderAndroidView extends PlatformViewRenderBox {
     Size targetSize;
     do {
       targetSize = size;
-      _currentTextureSize = await _viewController.setSize(targetSize);
+      if (_viewController.isCreated) {
+        _currentTextureSize = await _viewController.setSize(targetSize);
+      } else {
+        await _viewController.create(size: targetSize);
+        _currentTextureSize = targetSize;
+      }
       // We've resized the platform view to targetSize, but it is possible that
       // while we were resizing the render object's size was changed again.
       // In that case we will resize the platform view again.

packages/flutter/lib/src/services/platform_views.dart

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-
+import 'dart:async';
 import 'dart:typed_data';
 import 'dart:ui';
 
@@ -750,16 +750,17 @@ abstract class AndroidViewController extends PlatformViewController {
     return ((pointerId << 8) & 0xff00) | (action & 0xff);
   }
 
+  /// Sends the message to dispose the platform view.
   Future<void> _sendDisposeMessage();
-  Future<void> _sendCreateMessage();
 
-  /// Creates the Android View.
-  ///
-  /// Throws an [AssertionError] if view was already disposed.
-  Future<void> create() async {
+  /// Sends the message to create the platform view with an initial [size].
+  Future<void> _sendCreateMessage({Size? size});
+
+  @override
+  Future<void> create({Size? size}) async {
     assert(_state != _AndroidViewState.disposed, 'trying to create a disposed Android view');
 
-    await _sendCreateMessage();
+    await _sendCreateMessage(size: size);
 
     _state = _AndroidViewState.created;
     for (final PlatformViewCreatedCallback callback in _platformViewCreatedCallbacks) {
@@ -970,7 +971,7 @@ class ExpensiveAndroidViewController extends AndroidViewController {
         );
 
   @override
-  Future<void> _sendCreateMessage() {
+  Future<void> _sendCreateMessage({Size? size}) {
     final Map<String, dynamic> args = <String, dynamic>{
       'id': viewId,
       'viewType': _viewType,
@@ -996,8 +997,7 @@ class ExpensiveAndroidViewController extends AndroidViewController {
 
   @override
   Future<void> _sendDisposeMessage() {
-    return SystemChannels.platform_views
-        .invokeMethod<void>('dispose', <String, dynamic>{
+    return SystemChannels.platform_views.invokeMethod<void>('dispose', <String, dynamic>{
       'id': viewId,
       'hybrid': true,
     });
@@ -1014,11 +1014,12 @@ class ExpensiveAndroidViewController extends AndroidViewController {
   }
 }
 
-/// Controls an Android view that is rendered to a texture.
+/// Controls an Android view that is rendered as a texture.
+/// This is typically used by [AndroidView] to display a View in the Android view hierarchy.
 ///
-/// This is typically used by [AndroidView] to display an Android View in the Android view hierarchy.
+/// The platform view is created by calling [create] with an initial size.
 ///
-/// Typically created with [PlatformViewsService.initAndroidView].
+/// The controller is typically created with [PlatformViewsService.initAndroidView].
 class TextureAndroidViewController extends AndroidViewController {
   TextureAndroidViewController._({
     required int viewId,
@@ -1044,25 +1045,16 @@ class TextureAndroidViewController extends AndroidViewController {
   @override
   int? get textureId => _textureId;
 
-  /// The size used to create the platform view.
-  Size? _initialSize;
-
   /// The current offset of the platform view.
   Offset _off = Offset.zero;
 
   @override
   Future<Size> setSize(Size size) async {
-    assert(_state != _AndroidViewState.disposed, 'trying to size a disposed Android View. View id: $viewId');
-
+    assert(_state != _AndroidViewState.disposed, 'Android view is disposed. View id: $viewId');
+    assert(_state != _AndroidViewState.waitingForSize, 'Android view must have an initial size. View id: $viewId');
     assert(size != null);
     assert(!size.isEmpty);
 
-    if (_state == _AndroidViewState.waitingForSize) {
-      _initialSize = size;
-      await create();
-      return size;
-    }
-
     final Map<Object?, Object?>? meta = await SystemChannels.platform_views.invokeMapMethod<Object?, Object?>(
       'resize',
       <String, dynamic>{
@@ -1077,6 +1069,15 @@ class TextureAndroidViewController extends AndroidViewController {
     return Size(meta!['width']! as double, meta['height']! as double);
   }
 
+  @override
+  Future<void> create({Size? size}) async {
+    if (size == null)
+      return;
+    assert(_state == _AndroidViewState.waitingForSize, 'Android view is already sized. View id: $viewId');
+    assert(!size.isEmpty);
+    return super.create(size: size);
+  }
+
   @override
   Future<void> setOffset(Offset off) async {
     if (off == _off)
@@ -1100,27 +1101,18 @@ class TextureAndroidViewController extends AndroidViewController {
     );
   }
 
-  /// Creates the Android View.
-  ///
-  /// This should not be called before [AndroidViewController.setSize].
-  ///
-  /// Throws an [AssertionError] if view was already disposed.
   @override
-  Future<void> create() async {
-    if (_initialSize != null)
-      return super.create();
-  }
+  Future<void> _sendCreateMessage({Size? size}) async {
+    if (size == null)
+      return;
 
-  @override
-  Future<void> _sendCreateMessage() async {
-    assert(_initialSize != null, 'trying to create $TextureAndroidViewController without setting an initial size.');
-    assert(!_initialSize!.isEmpty, 'trying to create $TextureAndroidViewController without setting a valid size.');
+    assert(!size.isEmpty, 'trying to create $TextureAndroidViewController without setting a valid size.');
 
     final Map<String, dynamic> args = <String, dynamic>{
       'id': viewId,
       'viewType': _viewType,
-      'width': _initialSize!.width,
-      'height': _initialSize!.height,
+      'width': size.width,
+      'height': size.height,
       'direction': AndroidViewController._getAndroidDirection(_layoutDirection),
     };
     if (_creationParams != null) {
@@ -1230,6 +1222,13 @@ abstract class PlatformViewController {
   /// Dispatches the `event` to the platform view.
   Future<void> dispatchPointerEvent(PointerEvent event);
 
+  /// Creates the platform view with the initial [size].
+  ///
+  /// [size] is the view's initial size in logical pixel.
+  /// [size] can be omitted if the concrete implementation doesn't require an initial size
+  /// to create the platform view.
+  Future<void> create({Size? size}) async {}
+
   /// Disposes the platform view.
   ///
   /// The [PlatformViewController] is unusable after calling dispose.

packages/flutter/lib/src/widgets/platform_view.dart

@@ -805,7 +805,6 @@ typedef CreatePlatformViewCallback = PlatformViewController Function(PlatformVie
 /// The `surfaceFactory` and the `onCreatePlatformView` are only called when the
 /// state of this widget is initialized, or when the `viewType` changes.
 class PlatformViewLink extends StatefulWidget {
-
   /// Construct a [PlatformViewLink] widget.
   ///
   /// The `surfaceFactory` and the `onCreatePlatformView` must not be null.
@@ -842,11 +841,19 @@ class PlatformViewLink extends StatefulWidget {
 class _PlatformViewLinkState extends State<PlatformViewLink> {
   int? _id;
   PlatformViewController? _controller;
+  bool _platformViewCreated = false;
   Widget? _surface;
   FocusNode? _focusNode;
 
   @override
   Widget build(BuildContext context) {
+    if (_controller == null) {
+      return const SizedBox.expand();
+    }
+    if (!_platformViewCreated) {
+      // Depending on the platform, the initial size can be used to size the platform view.
+      return _PlatformViewPlaceHolder(onLayout: (Size size) => _controller!.create(size: size));
+    }
     _surface ??= widget._surfaceFactory(context, _controller!);
     return Focus(
       focusNode: _focusNode,
@@ -881,12 +888,18 @@ class _PlatformViewLinkState extends State<PlatformViewLink> {
       PlatformViewCreationParams._(
         id: _id!,
         viewType: widget.viewType,
-        onPlatformViewCreated: (_) {},
+        onPlatformViewCreated: _onPlatformViewCreated,
         onFocusChanged: _handlePlatformFocusChanged,
       ),
     );
   }
 
+  void _onPlatformViewCreated(int id) {
+    setState(() {
+      _platformViewCreated = true;
+    });
+  }
+
   void _handleFrameworkFocusChanged(bool isFocused) {
     if (!isFocused) {
       _controller?.clearFocus();
@@ -1064,3 +1077,48 @@ class AndroidViewSurface extends PlatformViewSurface {
     return renderBox;
   }
 }
+
+/// A callback used to notify the size of the platform view placeholder.
+/// This size is the initial size of the platform view.
+typedef _OnLayoutCallback = void Function(Size size);
+
+/// A [RenderBox] that notifies its size to the owner after a layout.
+class _PlatformViewPlaceholderBox extends RenderConstrainedBox {
+  _PlatformViewPlaceholderBox({
+    required this.onLayout,
+  }) : super(additionalConstraints: const BoxConstraints.tightFor(
+      width: double.infinity,
+      height: double.infinity,
+    ));
+
+  _OnLayoutCallback onLayout;
+
+  @override
+  void performLayout() {
+    super.performLayout();
+    onLayout(size);
+  }
+}
+
+/// When a platform view is in the widget hierarchy, this widget is used to capture
+/// the size of the platform view after the first layout.
+/// This placeholder is basically a [SizedBox.expand] with a [onLayout] callback to
+/// notify the size of the render object to its parent.
+class _PlatformViewPlaceHolder extends SingleChildRenderObjectWidget {
+  const _PlatformViewPlaceHolder({
+    Key? key,
+    required this.onLayout,
+  }) : super(key: key);
+
+  final _OnLayoutCallback onLayout;
+
+  @override
+  _PlatformViewPlaceholderBox createRenderObject(BuildContext context) {
+    return _PlatformViewPlaceholderBox(onLayout: onLayout);
+  }
+
+  @override
+  void updateRenderObject(BuildContext context, _PlatformViewPlaceholderBox renderObject) {
+    renderObject.onLayout = onLayout;
+  }
+}

packages/flutter/test/services/fake_platform_views.dart

@@ -117,7 +117,7 @@ class FakeAndroidViewController implements AndroidViewController {
   }
 
   @override
-  Future<void> create() async {}
+  Future<void> create({Size? size}) async {}
 
   @override
   List<PlatformViewCreatedCallback> get createdCallbacks => <PlatformViewCreatedCallback>[];

packages/flutter/test/widgets/platform_view_test.dart

@@ -2312,6 +2312,50 @@ void main() {
       expect(factoryInvocationCount, 1);
     });
 
+    testWidgets(
+      'PlatformViewLink Widget init, should create a placeholder widget before onPlatformViewCreated and a PlatformViewSurface after',
+      (WidgetTester tester) async {
+        final int currentViewId = platformViewsRegistry.getNextPlatformViewId();
+        late int createdPlatformViewId;
+
+        late PlatformViewCreatedCallback onPlatformViewCreatedCallBack;
+
+        final PlatformViewLink platformViewLink = PlatformViewLink(
+          viewType: 'webview',
+          onCreatePlatformView: (PlatformViewCreationParams params) {
+            onPlatformViewCreatedCallBack = params.onPlatformViewCreated;
+            createdPlatformViewId = params.id;
+            return FakePlatformViewController(params.id);
+          },
+          surfaceFactory: (BuildContext context, PlatformViewController controller) {
+            return PlatformViewSurface(
+              gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{},
+              controller: controller,
+              hitTestBehavior: PlatformViewHitTestBehavior.opaque,
+            );
+          },
+        );
+
+        await tester.pumpWidget(platformViewLink);
+
+        expect(
+          tester.allWidgets.map((Widget widget) => widget.runtimeType.toString()).toList(),
+          equals(<String>['PlatformViewLink', '_PlatformViewPlaceHolder']),
+        );
+
+        onPlatformViewCreatedCallBack(createdPlatformViewId);
+
+        await tester.pump();
+
+        expect(
+          tester.allWidgets.map((Widget widget) => widget.runtimeType.toString()).toList(),
+          equals(<String>['PlatformViewLink', 'Focus', '_FocusMarker', 'Semantics', 'PlatformViewSurface']),
+        );
+
+        expect(createdPlatformViewId, currentViewId + 1);
+      },
+    );
+
     testWidgets('PlatformViewLink Widget dispose', (WidgetTester tester) async {
       late FakePlatformViewController disposedController;
       final PlatformViewLink platformViewLink = PlatformViewLink(