Added keyEvent support for iOS 13.4+

shell/platform/darwin/ios/framework/Headers/FlutterEngine.h

@@ -322,6 +322,14 @@ FLUTTER_EXPORT
  */
 @property(nonatomic, readonly) FlutterBasicMessageChannel* settingsChannel;
 
+/**
+ * The `FlutterBasicMessageChannel` used for communicating key events
+ * from physical keyboards
+ *
+ * Can be nil after `destroyContext` is called.
+ */
+@property(nonatomic, readonly) FlutterBasicMessageChannel* keyEventChannel;
+
 /**
  * The `NSURL` of the observatory for the service isolate.
  *

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

@@ -77,6 +77,7 @@ @implementation FlutterEngine {
   fml::scoped_nsobject<FlutterBasicMessageChannel> _lifecycleChannel;
   fml::scoped_nsobject<FlutterBasicMessageChannel> _systemChannel;
   fml::scoped_nsobject<FlutterBasicMessageChannel> _settingsChannel;
+  fml::scoped_nsobject<FlutterBasicMessageChannel> _keyEventChannel;
 
   int64_t _nextTextureId;
 
@@ -326,6 +327,9 @@ - (FlutterBasicMessageChannel*)systemChannel {
 - (FlutterBasicMessageChannel*)settingsChannel {
   return _settingsChannel.get();
 }
+- (FlutterBasicMessageChannel*)keyEventChannel {
+  return _keyEventChannel.get();
+}
 
 - (NSURL*)observatoryUrl {
   return [_publisher.get() url];
@@ -340,6 +344,7 @@ - (void)resetChannels {
   _lifecycleChannel.reset();
   _systemChannel.reset();
   _settingsChannel.reset();
+  _keyEventChannel.reset();
 }
 
 - (void)startProfiler:(NSString*)threadLabel {
@@ -412,6 +417,11 @@ - (void)setupChannels {
       binaryMessenger:self.binaryMessenger
                 codec:[FlutterJSONMessageCodec sharedInstance]]);
 
+  _keyEventChannel.reset([[FlutterBasicMessageChannel alloc]
+         initWithName:@"flutter/keyevent"
+      binaryMessenger:self.binaryMessenger
+                codec:[FlutterJSONMessageCodec sharedInstance]]);
+
   _textInputPlugin.reset([[FlutterTextInputPlugin alloc] init]);
   _textInputPlugin.get().textInputDelegate = self;
 

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

@@ -964,6 +964,57 @@ - (void)keyboardWillBeHidden:(NSNotification*)notification {
   [self updateViewportMetrics];
 }
 
+- (void)dispatchPresses:(NSSet<UIPress*>*)presses API_AVAILABLE(ios(13.4)) {
+  if (@available(iOS 13.4, *)) {
+    for (UIPress* press in presses) {
+      if (press.key == nil) {
+        continue;
+      }
+      NSMutableDictionary* keyMessage = [@{
+        @"keymap" : @"ios",
+        @"type" : @"unknown",
+        @"keyCode" : @(press.key.keyCode),
+        @"modifiers" : @(press.key.modifierFlags),
+        @"characters" : press.key.characters,
+        @"charactersIgnoringModifiers" : press.key.charactersIgnoringModifiers
+      } mutableCopy];
+
+      if (press.phase == UIPressPhaseBegan) {
+        keyMessage[@"type"] = @"keydown";
+      } else if (press.phase == UIPressPhaseEnded || press.phase == UIPressPhaseCancelled) {
+        keyMessage[@"type"] = @"keyup";
+      }
+
+      [[_engine.get() keyEventChannel] sendMessage:keyMessage];
+    }
+  }
+}
+
+- (void)pressesBegan:(NSSet<UIPress*>*)presses withEvent:(UIEvent*)event API_AVAILABLE(ios(9.0)) {
+  if (@available(iOS 13.4, *)) {
+    [self dispatchPresses:presses];
+  }
+}
+
+- (void)pressesChanged:(NSSet<UIPress*>*)presses withEvent:(UIEvent*)event API_AVAILABLE(ios(9.0)) {
+  if (@available(iOS 13.4, *)) {
+    [self dispatchPresses:presses];
+  }
+}
+
+- (void)pressesEnded:(NSSet<UIPress*>*)presses withEvent:(UIEvent*)event API_AVAILABLE(ios(9.0)) {
+  if (@available(iOS 13.4, *)) {
+    [self dispatchPresses:presses];
+  }
+}
+
+- (void)pressesCancelled:(NSSet<UIPress*>*)presses
+               withEvent:(UIEvent*)event API_AVAILABLE(ios(9.0)) {
+  if (@available(iOS 13.4, *)) {
+    [self dispatchPresses:presses];
+  }
+}
+
 #pragma mark - Orientation updates
 
 - (void)onOrientationPreferencesUpdated:(NSNotification*)notification {