Fix issue viewdidload call while init FlutterViewController

shell/platform/darwin/ios/framework/Source/FlutterEngine.mm

@@ -204,6 +204,10 @@ - (void)setViewController:(FlutterViewController*)viewController {
   }
 }
 
+- (void)attachView {
+  self.iosPlatformView->attachView();
+}
+
 - (void)setFlutterViewControllerWillDeallocObserver:(id<NSObject>)observer {
   if (observer != _flutterViewControllerWillDeallocObserver) {
     if (_flutterViewControllerWillDeallocObserver) {

shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h

@@ -44,6 +44,7 @@
 - (FlutterTextInputPlugin*)textInputPlugin;
 - (void)launchEngine:(NSString*)entrypoint libraryURI:(NSString*)libraryOrNil;
 - (BOOL)createShell:(NSString*)entrypoint libraryURI:(NSString*)libraryOrNil;
+- (void)attachView;
 
 @end
 

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -441,15 +441,25 @@ - (void)surfaceUpdated:(BOOL)appeared {
 
 #pragma mark - UIViewController lifecycle notifications
 
-- (void)viewWillAppear:(BOOL)animated {
-  TRACE_EVENT0("flutter", "viewWillAppear");
+- (void)viewDidLoad {
+  TRACE_EVENT0("flutter", "viewDidLoad");
 
   if (_engineNeedsLaunch) {
     [_engine.get() launchEngine:nil libraryURI:nil];
     [_engine.get() setViewController:self];
     _engineNeedsLaunch = NO;
   }
 
+  FML_DCHECK([_engine.get() viewController] != nil)
+      << "FlutterViewController::viewWillAppear:AttachView ViewController was nil";
+  [_engine.get() attachView];
+
+  [super viewDidLoad];
+}
+
+- (void)viewWillAppear:(BOOL)animated {
+  TRACE_EVENT0("flutter", "viewWillAppear");
+
   // Send platform settings to Flutter, e.g., platform brightness.
   [self onUserSettingsChanged:nil];
 

shell/platform/darwin/ios/framework/Source/FlutterViewControllerTest.m

@@ -11,6 +11,10 @@
 
 FLUTTER_ASSERT_ARC
 
+@interface FlutterEngine ()
+- (BOOL)createShell:(NSString*)entrypoint libraryURI:(NSString*)libraryURI;
+@end
+
 extern NSNotificationName const FlutterViewControllerWillDealloc;
 
 /// A simple mock class for FlutterEngine.
@@ -457,4 +461,16 @@ - (void)testWillDeallocNotification {
   [self waitForExpectations:@[ expectation ] timeout:1.0];
 }
 
+- (void)testDoesntLoadViewInInit {
+  XCTestExpectation* expectation =
+      [[XCTestExpectation alloc] initWithDescription:@"notification called"];
+  FlutterDartProject* project = [[FlutterDartProject alloc] init];
+  FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"foobar" project:project];
+  [engine createShell:@"" libraryURI:@""];
+  FlutterViewController* realVC = [[FlutterViewController alloc] initWithEngine:engine
+                                                                        nibName:nil
+                                                                         bundle:nil];
+  XCTAssertFalse([realVC isViewLoaded], @"shouldn't have loaded since it hasn't been shown");
+}
+
 @end

shell/platform/darwin/ios/platform_view_ios.h

@@ -34,6 +34,7 @@ class PlatformViewIOS final : public PlatformView {
 
   fml::WeakPtr<FlutterViewController> GetOwnerViewController() const;
   void SetOwnerViewController(fml::WeakPtr<FlutterViewController> owner_controller);
+  void attachView();
 
   void RegisterExternalTexture(int64_t id, NSObject<FlutterTexture>* texture);
 

shell/platform/darwin/ios/platform_view_ios.mm

@@ -64,20 +64,25 @@
                                                        owner_controller_.reset();
                                                      }] retain]);
 
-  if (owner_controller_) {
-    ios_surface_ =
-        [static_cast<FlutterView*>(owner_controller.get().view) createSurface:gl_context_];
-    FML_DCHECK(ios_surface_ != nullptr);
-
-    if (accessibility_bridge_) {
-      accessibility_bridge_.reset(
-          new AccessibilityBridge(static_cast<FlutterView*>(owner_controller_.get().view), this,
-                                  [owner_controller.get() platformViewsController]));
-    }
-    // Do not call `NotifyCreated()` here - let FlutterViewController take care
-    // of that when its Viewport is sized.  If `NotifyCreated()` is called here,
-    // it can occasionally get invoked before the viewport is sized resulting in
-    // a framebuffer that will not be able to completely attach.
+  if (owner_controller_ && [owner_controller_.get() isViewLoaded]) {
+    this->attachView();
+  }
+  // Do not call `NotifyCreated()` here - let FlutterViewController take care
+  // of that when its Viewport is sized.  If `NotifyCreated()` is called here,
+  // it can occasionally get invoked before the viewport is sized resulting in
+  // a framebuffer that will not be able to completely attach.
+}
+
+void PlatformViewIOS::attachView() {
+  FML_DCHECK(owner_controller_);
+  ios_surface_ =
+      [static_cast<FlutterView*>(owner_controller_.get().view) createSurface:gl_context_];
+  FML_DCHECK(ios_surface_ != nullptr);
+
+  if (accessibility_bridge_) {
+    accessibility_bridge_.reset(
+        new AccessibilityBridge(static_cast<FlutterView*>(owner_controller_.get().view), this,
+                                [owner_controller_.get() platformViewsController]));
   }
 }