[macOS] Ensure first responder is consistent during and after text input

shell/platform/darwin/macos/framework/Source/FlutterTextInputPlugin.mm

@@ -384,10 +384,7 @@ - (void)dealloc {
 
 - (void)resignAndRemoveFromSuperview {
   if (self.superview != nil) {
-    // With accessiblity enabled TextInputPlugin is inside _client, so take the
-    // nextResponder from the _client.
-    NSResponder* nextResponder = _client != nil ? _client.nextResponder : self.nextResponder;
-    [self.window makeFirstResponder:nextResponder];
+    [self.window makeFirstResponder:_flutterViewController.flutterView];
     [self removeFromSuperview];
   }
 }

shell/platform/darwin/macos/framework/Source/FlutterTextInputPluginTest.mm

@@ -2049,6 +2049,41 @@ - (bool)testSelectorsAreForwardedToFramework {
   ASSERT_FALSE(window.firstResponder == viewController.textInputPlugin);
 }
 
+TEST(FlutterTextInputPluginTest, FirstResponderIsCorrect) {
+  FlutterEngine* engine = CreateTestEngine();
+  FlutterViewController* viewController = [[FlutterViewController alloc] initWithEngine:engine
+                                                                                nibName:nil
+                                                                                 bundle:nil];
+  [viewController loadView];
+
+  NSWindow* window = [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 800, 600)
+                                                 styleMask:NSBorderlessWindowMask
+                                                   backing:NSBackingStoreBuffered
+                                                     defer:NO];
+  window.contentView = viewController.view;
+
+  ASSERT_TRUE(viewController.flutterView.acceptsFirstResponder);
+
+  [window makeFirstResponder:viewController.flutterView];
+
+  [viewController.textInputPlugin
+      handleMethodCall:[FlutterMethodCall methodCallWithMethodName:@"TextInput.show" arguments:@[]]
+                result:^(id){
+                }];
+
+  ASSERT_TRUE(window.firstResponder == viewController.textInputPlugin);
+
+  ASSERT_FALSE(viewController.flutterView.acceptsFirstResponder);
+
+  [viewController.textInputPlugin
+      handleMethodCall:[FlutterMethodCall methodCallWithMethodName:@"TextInput.hide" arguments:@[]]
+                result:^(id){
+                }];
+
+  ASSERT_TRUE(viewController.flutterView.acceptsFirstResponder);
+  ASSERT_TRUE(window.firstResponder == viewController.flutterView);
+}
+
 TEST(FlutterTextInputPluginTest, HasZeroSizeAndClipsToBounds) {
   id engineMock = flutter::testing::CreateMockFlutterEngine(@"");
   id binaryMessengerMock = OCMProtocolMock(@protocol(FlutterBinaryMessenger));

shell/platform/darwin/macos/framework/Source/FlutterView.h

@@ -23,13 +23,19 @@ typedef int64_t FlutterViewId;
 constexpr FlutterViewId kFlutterImplicitViewId = 0ll;
 
 /**
- * Listener for view resizing.
+ * Delegate for FlutterView.
  */
-@protocol FlutterViewReshapeListener <NSObject>
+@protocol FlutterViewDelegate <NSObject>
 /**
  * Called when the view's backing store changes size.
  */
 - (void)viewDidReshape:(nonnull NSView*)view;
+
+/**
+ * Called to determine whether the view should accept first responder status.
+ */
+- (BOOL)viewShouldAcceptFirstResponder:(nonnull NSView*)view;
+
 @end
 
 /**
@@ -43,7 +49,7 @@ constexpr FlutterViewId kFlutterImplicitViewId = 0ll;
  */
 - (nullable instancetype)initWithMTLDevice:(nonnull id<MTLDevice>)device
                               commandQueue:(nonnull id<MTLCommandQueue>)commandQueue
-                           reshapeListener:(nonnull id<FlutterViewReshapeListener>)reshapeListener
+                                  delegate:(nonnull id<FlutterViewDelegate>)delegate
                         threadSynchronizer:(nonnull FlutterThreadSynchronizer*)threadSynchronizer
                                     viewId:(int64_t)viewId NS_DESIGNATED_INITIALIZER;
 

shell/platform/darwin/macos/framework/Source/FlutterView.mm

@@ -11,7 +11,7 @@
 
 @interface FlutterView () <FlutterSurfaceManagerDelegate> {
   int64_t _viewId;
-  __weak id<FlutterViewReshapeListener> _reshapeListener;
+  __weak id<FlutterViewDelegate> _viewDelegate;
   FlutterThreadSynchronizer* _threadSynchronizer;
   FlutterSurfaceManager* _surfaceManager;
 }
@@ -22,7 +22,7 @@ @implementation FlutterView
 
 - (instancetype)initWithMTLDevice:(id<MTLDevice>)device
                      commandQueue:(id<MTLCommandQueue>)commandQueue
-                  reshapeListener:(id<FlutterViewReshapeListener>)reshapeListener
+                         delegate:(id<FlutterViewDelegate>)delegate
                threadSynchronizer:(FlutterThreadSynchronizer*)threadSynchronizer
                            viewId:(int64_t)viewId {
   self = [super initWithFrame:NSZeroRect];
@@ -31,7 +31,7 @@ - (instancetype)initWithMTLDevice:(id<MTLDevice>)device
     [self setBackgroundColor:[NSColor blackColor]];
     [self setLayerContentsRedrawPolicy:NSViewLayerContentsRedrawDuringViewResize];
     _viewId = viewId;
-    _reshapeListener = reshapeListener;
+    _viewDelegate = delegate;
     _threadSynchronizer = threadSynchronizer;
     _surfaceManager = [[FlutterSurfaceManager alloc] initWithDevice:device
                                                        commandQueue:commandQueue
@@ -54,7 +54,7 @@ - (void)reshaped {
   [_threadSynchronizer beginResizeForView:_viewId
                                      size:scaledSize
                                    notify:^{
-                                     [_reshapeListener viewDidReshape:self];
+                                     [_viewDelegate viewDidReshape:self];
                                    }];
 }
 
@@ -89,7 +89,9 @@ - (BOOL)acceptsFirstMouse:(NSEvent*)event {
 }
 
 - (BOOL)acceptsFirstResponder {
-  return YES;
+  // This is to ensure that FlutterView does not take first responder status from TextInputPlugin
+  // on mouse clicks.
+  return [_viewDelegate viewShouldAcceptFirstResponder:self];
 }
 
 - (void)cursorUpdate:(NSEvent*)event {
@@ -104,7 +106,7 @@ - (void)cursorUpdate:(NSEvent*)event {
 - (void)viewDidChangeBackingProperties {
   [super viewDidChangeBackingProperties];
   // Force redraw
-  [_reshapeListener viewDidReshape:self];
+  [_viewDelegate viewDidReshape:self];
 }
 
 - (BOOL)layer:(CALayer*)layer

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

@@ -169,7 +169,7 @@ - (void)setBackgroundColor:(NSColor*)color;
 /**
  * Private interface declaration for FlutterViewController.
  */
-@interface FlutterViewController () <FlutterViewReshapeListener>
+@interface FlutterViewController () <FlutterViewDelegate>
 
 /**
  * The tracking area used to generate hover events, if enabled.
@@ -831,7 +831,7 @@ - (nonnull FlutterView*)createFlutterViewWithMTLDevice:(id<MTLDevice>)device
                                           commandQueue:(id<MTLCommandQueue>)commandQueue {
   return [[FlutterView alloc] initWithMTLDevice:device
                                    commandQueue:commandQueue
-                                reshapeListener:self
+                                       delegate:self
                              threadSynchronizer:_threadSynchronizer
                                          viewId:_viewId];
 }
@@ -851,15 +851,24 @@ - (NSString*)lookupKeyForAsset:(NSString*)asset fromPackage:(NSString*)package {
   return [FlutterDartProject lookupKeyForAsset:asset fromPackage:package];
 }
 
-#pragma mark - FlutterViewReshapeListener
+#pragma mark - FlutterViewDelegate
 
 /**
  * Responds to view reshape by notifying the engine of the change in dimensions.
  */
 - (void)viewDidReshape:(NSView*)view {
+  FML_DCHECK(view == _flutterView);
   [_engine updateWindowMetricsForViewController:self];
 }
 
+- (BOOL)viewShouldAcceptFirstResponder:(NSView*)view {
+  FML_DCHECK(view == _flutterView);
+  // Only allow FlutterView to become first responder if TextInputPlugin is
+  // not active. Otherwise a mouse event inside FlutterView would cause the
+  // TextInputPlugin to lose first responder status.
+  return !_textInputPlugin.isFirstResponder;
+}
+
 #pragma mark - FlutterPluginRegistry
 
 - (id<FlutterPluginRegistrar>)registrarForPlugin:(NSString*)pluginName {

shell/platform/darwin/macos/framework/Source/FlutterViewTest.mm

@@ -10,25 +10,29 @@
 
 constexpr int64_t kImplicitViewId = 0ll;
 
-@interface TestReshapeListener : NSObject <FlutterViewReshapeListener>
+@interface TestFlutterViewDelegate : NSObject <FlutterViewDelegate>
 
 @end
 
-@implementation TestReshapeListener
+@implementation TestFlutterViewDelegate
 
 - (void)viewDidReshape:(nonnull NSView*)view {
 }
 
+- (BOOL)viewShouldAcceptFirstResponder:(NSView*)view {
+  return YES;
+}
+
 @end
 
 TEST(FlutterView, ShouldInheritContentsScaleReturnsYes) {
   id<MTLDevice> device = MTLCreateSystemDefaultDevice();
   id<MTLCommandQueue> queue = [device newCommandQueue];
-  TestReshapeListener* listener = [[TestReshapeListener alloc] init];
+  TestFlutterViewDelegate* delegate = [[TestFlutterViewDelegate alloc] init];
   FlutterThreadSynchronizer* threadSynchronizer = [[FlutterThreadSynchronizer alloc] init];
   FlutterView* view = [[FlutterView alloc] initWithMTLDevice:device
                                                 commandQueue:queue
-                                             reshapeListener:listener
+                                                    delegate:delegate
                                           threadSynchronizer:threadSynchronizer
                                                       viewId:kImplicitViewId];
   EXPECT_EQ([view layer:view.layer shouldInheritContentsScale:3.0 fromWindow:view.window], YES);