Report keyboard show notifications with an empty frame as hide events (#59559)

packages/react-native/React/CoreModules/RCTKeyboardObserver.mm

@@ -18,6 +18,31 @@
 @interface RCTKeyboardObserver () <NativeKeyboardObserverSpec>
 @end
 
+#if !TARGET_OS_TV
+@interface UIResponder (RCTKeyboardObserver)
+- (void)reactCollectFirstResponder:(NSMutableArray<UIResponder *> *)firstResponders;
+@end
+
+@implementation UIResponder (RCTKeyboardObserver)
+
+- (void)reactCollectFirstResponder:(NSMutableArray<UIResponder *> *)firstResponders
+{
+  if (self.isFirstResponder) {
+    [firstResponders addObject:self];
+  }
+}
+
+@end
+
+// UIKit sends a nil-targeted action to the first responder, if there is one, and then up its responder chain.
+static BOOL RCTHasFirstResponder()
+{
+  NSMutableArray<UIResponder *> *firstResponders = [NSMutableArray new];
+  [RCTSharedApplication() sendAction:@selector(reactCollectFirstResponder:) to:nil from:firstResponders forEvent:nil];
+  return firstResponders.count > 0;
+}
+#endif
+
 @implementation RCTKeyboardObserver
 
 RCT_EXPORT_MODULE()
@@ -69,8 +94,34 @@ -(void)EVENT : (NSNotification *)notification
     [self sendEventWithName:@ #EVENT body:RCTParseKeyboardNotification(notification)]; \
   }
 
+#if !TARGET_OS_TV
+// UIKit can post a show notification with an empty end frame while no view is first responder, for example when the
+// window is resized. No keyboard can be shown then, so it is sent as the matching hide.
+- (void)keyboardWillShow:(NSNotification *)notification
+{
+  if (self.callableJSModules == nil) {
+    return;
+  }
+  BOOL isShown =
+      !CGRectIsEmpty([notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue]) || RCTHasFirstResponder();
+  [self sendEventWithName:isShown ? @"keyboardWillShow" : @"keyboardWillHide"
+                     body:RCTParseKeyboardNotification(notification)];
+}
+
+- (void)keyboardDidShow:(NSNotification *)notification
+{
+  if (self.callableJSModules == nil) {
+    return;
+  }
+  BOOL isShown =
+      !CGRectIsEmpty([notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue]) || RCTHasFirstResponder();
+  [self sendEventWithName:isShown ? @"keyboardDidShow" : @"keyboardDidHide"
+                     body:RCTParseKeyboardNotification(notification)];
+}
+#else
 IMPLEMENT_KEYBOARD_HANDLER(keyboardWillShow)
 IMPLEMENT_KEYBOARD_HANDLER(keyboardDidShow)
+#endif
 IMPLEMENT_KEYBOARD_HANDLER(keyboardWillHide)
 IMPLEMENT_KEYBOARD_HANDLER(keyboardDidHide)
 IMPLEMENT_KEYBOARD_HANDLER(keyboardWillChangeFrame)

packages/react-native/React/Tests/CoreModules/RCTKeyboardObserverTests.m

@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <React/RCTBridgeModule.h>
+#import <React/RCTKeyboardObserver.h>
+#import <XCTest/XCTest.h>
+
+#if !TARGET_OS_TV
+
+@interface RCTKeyboardObserver (Tests)
+- (void)keyboardWillShow:(NSNotification *)notification;
+- (void)keyboardDidShow:(NSNotification *)notification;
+- (void)keyboardWillHide:(NSNotification *)notification;
+- (void)keyboardDidHide:(NSNotification *)notification;
+- (void)keyboardWillChangeFrame:(NSNotification *)notification;
+- (void)keyboardDidChangeFrame:(NSNotification *)notification;
+@end
+
+@interface RCTRecordingKeyboardObserver : RCTKeyboardObserver
+@property (nonatomic, readonly) NSMutableArray<NSString *> *sentEventNames;
+@end
+
+@implementation RCTRecordingKeyboardObserver
+
+- (instancetype)init
+{
+  if (self = [super init]) {
+    _sentEventNames = [NSMutableArray new];
+  }
+  return self;
+}
+
+- (void)sendEventWithName:(NSString *)name body:(id)body
+{
+  [_sentEventNames addObject:name];
+}
+
+@end
+
+static NSNotification *keyboardNotification(NSNotificationName name, CGRect endFrame)
+{
+  return [NSNotification notificationWithName:name
+                                       object:nil
+                                     userInfo:@{
+                                       UIKeyboardFrameBeginUserInfoKey : [NSValue valueWithCGRect:CGRectZero],
+                                       UIKeyboardFrameEndUserInfoKey : [NSValue valueWithCGRect:endFrame],
+                                     }];
+}
+
+@interface RCTKeyboardObserverTests : XCTestCase
+@end
+
+@implementation RCTKeyboardObserverTests {
+  RCTCallableJSModules *_callableJSModules;
+  RCTRecordingKeyboardObserver *_observer;
+}
+
+- (void)setUp
+{
+  [super setUp];
+  _callableJSModules = [RCTCallableJSModules new];
+  _observer = [RCTRecordingKeyboardObserver new];
+  _observer.callableJSModules = _callableJSModules;
+}
+
+- (void)testShowWithKeyboardFrameIsSentAsShow
+{
+  CGRect keyboardFrame = CGRectMake(0, 389, 466, 289);
+  [_observer keyboardWillShow:keyboardNotification(UIKeyboardWillShowNotification, keyboardFrame)];
+  [_observer keyboardDidShow:keyboardNotification(UIKeyboardDidShowNotification, keyboardFrame)];
+
+  XCTAssertEqualObjects(_observer.sentEventNames, (@[ @"keyboardWillShow", @"keyboardDidShow" ]));
+}
+
+- (void)testShowWithKeyboardFrameAtTopIsSentAsShow
+{
+  CGRect keyboardFrameAtTop = CGRectMake(0, 0, 466, 289);
+  [_observer keyboardWillShow:keyboardNotification(UIKeyboardWillShowNotification, keyboardFrameAtTop)];
+  [_observer keyboardDidShow:keyboardNotification(UIKeyboardDidShowNotification, keyboardFrameAtTop)];
+
+  XCTAssertEqualObjects(_observer.sentEventNames, (@[ @"keyboardWillShow", @"keyboardDidShow" ]));
+}
+
+- (void)testShowWithEmptyFrameIsSentAsHide
+{
+  CGRect zeroHeightFrame = CGRectMake(0, 951, 669, 0);
+  [_observer keyboardWillShow:keyboardNotification(UIKeyboardWillShowNotification, zeroHeightFrame)];
+  [_observer keyboardDidShow:keyboardNotification(UIKeyboardDidShowNotification, zeroHeightFrame)];
+
+  CGRect zeroWidthFrame = CGRectMake(273, 0, 0, 264);
+  [_observer keyboardWillShow:keyboardNotification(UIKeyboardWillShowNotification, zeroWidthFrame)];
+  [_observer keyboardDidShow:keyboardNotification(UIKeyboardDidShowNotification, zeroWidthFrame)];
+
+  XCTAssertEqualObjects(
+      _observer.sentEventNames,
+      (@[ @"keyboardWillHide", @"keyboardDidHide", @"keyboardWillHide", @"keyboardDidHide" ]));
+}
+
+- (void)testShowWithEmptyFrameAndFirstResponderIsSentAsShow
+{
+  UIWindowScene *windowScene = (UIWindowScene *)UIApplication.sharedApplication.connectedScenes.anyObject;
+  if (windowScene == nil) {
+    XCTFail(@"The test host has no window scene");
+    return;
+  }
+  UIWindow *window = [[UIWindow alloc] initWithWindowScene:windowScene];
+  UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, 200, 40)];
+  [window addSubview:textField];
+  [window makeKeyAndVisible];
+  XCTAssertTrue([textField becomeFirstResponder]);
+
+  CGRect emptyFrame = CGRectMake(0, 1180, 0, 0);
+  [_observer keyboardWillShow:keyboardNotification(UIKeyboardWillShowNotification, emptyFrame)];
+  [_observer keyboardDidShow:keyboardNotification(UIKeyboardDidShowNotification, emptyFrame)];
+
+  [textField resignFirstResponder];
+  window.hidden = YES;
+  XCTAssertEqualObjects(_observer.sentEventNames, (@[ @"keyboardWillShow", @"keyboardDidShow" ]));
+}
+
+- (void)testHideAndFrameChangeAreUnchanged
+{
+  CGRect emptyFrame = CGRectMake(0, 678, 466, 0);
+  [_observer keyboardWillHide:keyboardNotification(UIKeyboardWillHideNotification, emptyFrame)];
+  [_observer keyboardDidHide:keyboardNotification(UIKeyboardDidHideNotification, emptyFrame)];
+  [_observer keyboardWillChangeFrame:keyboardNotification(UIKeyboardWillChangeFrameNotification, emptyFrame)];
+  [_observer keyboardDidChangeFrame:keyboardNotification(UIKeyboardDidChangeFrameNotification, emptyFrame)];
+
+  XCTAssertEqualObjects(
+      _observer.sentEventNames,
+      (@[ @"keyboardWillHide", @"keyboardDidHide", @"keyboardWillChangeFrame", @"keyboardDidChangeFrame" ]));
+}
+
+- (void)testNothingIsSentWithoutJSModules
+{
+  _observer.callableJSModules = nil;
+  [_observer keyboardWillShow:keyboardNotification(UIKeyboardWillShowNotification, CGRectMake(0, 951, 669, 0))];
+  [_observer keyboardWillShow:keyboardNotification(UIKeyboardWillShowNotification, CGRectMake(0, 389, 466, 289))];
+
+  XCTAssertEqual(_observer.sentEventNames.count, 0u);
+}
+
+@end
+
+#endif