Implement onRequestClose for iOS 13+ modals (#27618)

Summary:
Starting on iOS 13, a View Controller presented modally will have a "bottom sheet" style unless it's explicitly presented full screen.

Before this, modals on iOS were only being dismissed programatically by setting `visible={false}`. However, now that the dismissal can happen on the OS side, we need a callback to be able to update the state.

This PR reuses the `onRequestClose` prop already available for tvOS and Android, and makes it work on iOS for this use case.

Should fix https://github.com/facebook/react-native/issues/26892

## Changelog

[iOS] [Added] - Add support for onRequestClose prop to Modal on iOS 13+
Pull Request resolved: https://github.com/facebook/react-native/pull/27618

Test Plan:
I tested this using the RNTester app with the Modal example:

1. Select any presentation style other than the full screen ones
2. Tap Present and the modal is presented
3. Swipe down on the presented modal until dismissed
4. Tap Present again and a second modal should be presented

![Screen Recording 2019-12-26 at 14 05 33](https://user-images.githubusercontent.com/8739/71477208-0ac88c80-27e9-11ea-9342-8631426a9b80.gif)

Differential Revision: D19235758

Pulled By: shergin

fbshipit-source-id: c0f1d946c77ce8d1baab209eaef7eb64697851df

Libraries/Modal/Modal.js

@@ -95,7 +95,8 @@ export type Props = $ReadOnly<{|
 
   /**
    * The `onRequestClose` callback is called when the user taps the hardware
-   * back button on Android or the menu button on Apple TV.
+   * back button on Android, the menu button on Apple TV, or a modal is dismissed
+   * with a gesture on iOS 13+.
    *
    * This is required on Apple TV and Android.
    *

Libraries/Modal/RCTModalHostViewNativeComponent.js

@@ -70,7 +70,8 @@ type NativeProps = $ReadOnly<{|
 
   /**
    * The `onRequestClose` callback is called when the user taps the hardware
-   * back button on Android or the menu button on Apple TV.
+   * back button on Android, the menu button on Apple TV, or a modal is dismissed
+   * with a gesture on iOS 13+.
    *
    * This is required on Apple TV and Android.
    *

React/Fabric/Mounting/ComponentViews/Modal/RCTModalHostViewComponentView.mm

@@ -94,7 +94,9 @@ static ModalHostViewEventEmitter::OnOrientationChange onOrientationChangeStruct(
   return {orientation};
 }
 
-@interface RCTModalHostViewComponentView () <RCTFabricModalHostViewControllerDelegate>
+@interface RCTModalHostViewComponentView () <
+    RCTFabricModalHostViewControllerDelegate,
+    UIAdaptivePresentationControllerDelegate>
 
 @end
 
@@ -113,6 +115,7 @@ static ModalHostViewEventEmitter::OnOrientationChange onOrientationChangeStruct(
     _viewController = [RCTFabricModalHostViewController new];
     _viewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
     _viewController.delegate = self;
+    _viewController.presentationController.delegate = self;
   }
 
   return self;
@@ -217,6 +220,19 @@ static ModalHostViewEventEmitter::OnOrientationChange onOrientationChangeStruct(
   [childComponentView removeFromSuperview];
 }
 
+#pragma mark - UIAdaptivePresentationControllerDelegate
+
+- (void)presentationControllerDidDismiss:(UIPresentationController *)presentationController
+{
+  if (!_eventEmitter) {
+    return;
+  }
+
+  assert(std::dynamic_pointer_cast<ModalHostViewEventEmitter const>(_eventEmitter));
+  auto eventEmitter = std::static_pointer_cast<ModalHostViewEventEmitter const>(_eventEmitter);
+  eventEmitter->onRequestClose({});
+}
+
 @end
 
 Class<RCTComponentViewProtocol> RCTModalHostViewCls(void)

React/Views/RCTModalHostView.h

@@ -32,8 +32,9 @@
 @property (nonatomic, copy) NSArray<NSString *> *supportedOrientations;
 @property (nonatomic, copy) RCTDirectEventBlock onOrientationChange;
 
-#if TARGET_OS_TV
 @property (nonatomic, copy) RCTDirectEventBlock onRequestClose;
+
+#if TARGET_OS_TV
 @property (nonatomic, strong) RCTTVRemoteHandler *tvRemoteHandler;
 #endif
 

React/Views/RCTModalHostView.m

@@ -20,6 +20,10 @@
 #import "RCTTVRemoteHandler.h"
 #endif
 
+@interface RCTModalHostView () <UIAdaptivePresentationControllerDelegate>
+
+@end
+
 @implementation RCTModalHostView
 {
   __weak RCTBridge *_bridge;
@@ -46,6 +50,7 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:coder)
     UIView *containerView = [UIView new];
     containerView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
     _modalViewController.view = containerView;
+    _modalViewController.presentationController.delegate = self;
     _touchHandler = [[RCTTouchHandler alloc] initWithBridge:bridge];
 #if TARGET_OS_TV
     _menuButtonGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(menuButtonPressed:)];
@@ -70,10 +75,12 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:coder)
         _onRequestClose(nil);
     }
 }
+#endif
 
 - (void)setOnRequestClose:(RCTDirectEventBlock)onRequestClose
 {
   _onRequestClose = onRequestClose;
+  #if TARGET_OS_TV
   if (_reactSubview) {
     if (_onRequestClose && _menuButtonGestureRecognizer) {
       [_reactSubview addGestureRecognizer:_menuButtonGestureRecognizer];
@@ -81,8 +88,8 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:coder)
       [_reactSubview removeGestureRecognizer:_menuButtonGestureRecognizer];
     }
   }
+  #endif
 }
-#endif
 
 - (void)notifyForBoundsChange:(CGRect)newBounds
 {
@@ -257,4 +264,11 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:coder)
 }
 #endif
 
+- (void)presentationControllerDidDismiss:(UIPresentationController *)presentationController
+{
+  if (_onRequestClose) {
+    _onRequestClose(nil);
+  }
+}
+
 @end

React/Views/RCTModalHostViewManager.m

@@ -108,9 +108,6 @@ RCT_EXPORT_VIEW_PROPERTY(onShow, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(identifier, NSNumber)
 RCT_EXPORT_VIEW_PROPERTY(supportedOrientations, NSArray)
 RCT_EXPORT_VIEW_PROPERTY(onOrientationChange, RCTDirectEventBlock)
-
-#if TARGET_OS_TV
 RCT_EXPORT_VIEW_PROPERTY(onRequestClose, RCTDirectEventBlock)
-#endif
 
 @end