Fix cannot working Modal's onDismiss. (#29882)

Summary:
Fixes: #29455

Modal's onDismiss is not called on iOS.
This issue occurred the commit bd2b7d6 and was fixed the commit 27a3248.
However, the master and stable-0.63 branches do not have this modified commit applied to them.

## Changelog

<!-- Help reviewers and the release process by writing your own changelog entry. For an example, see:
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[iOS] [Fixed] - Modal's onDismiss prop will now be called successfully.

Pull Request resolved: #29882

Test Plan:
Tested on iOS with this change:

1. Set function Modal's onDismiss prop.
1. Set Modal's visible props is true. (show Modal)
1. Set Modal's visible props is false. (close Modal)
1. The set function in onDismiss is called.

Reviewed By: shergin

Differential Revision: D24648412

Pulled By: hramos

fbshipit-source-id: acf28fef21420117c845d3aed97e47b5dd4e9390

Libraries/Modal/Modal.js

@@ -12,6 +12,9 @@
 
 const AppContainer = require('../ReactNative/AppContainer');
 const I18nManager = require('../ReactNative/I18nManager');
+import NativeEventEmitter from '../EventEmitter/NativeEventEmitter';
+import NativeModalManager from './NativeModalManager';
+const Platform = require('../Utilities/Platform');
 const React = require('react');
 const ScrollView = require('../Components/ScrollView/ScrollView');
 const StyleSheet = require('../StyleSheet/StyleSheet');
@@ -26,6 +29,11 @@ import type {DirectEventHandler} from '../Types/CodegenTypes';
 import {type EventSubscription} from '../vendor/emitter/EventEmitter';
 import RCTModalHostView from './RCTModalHostViewNativeComponent';
 
+const ModalEventEmitter =
+  Platform.OS === 'ios' && NativeModalManager != null
+    ? new NativeEventEmitter(NativeModalManager)
+    : null;
+
 /**
  * The Modal component is a simple way to present content above an enclosing view.
  *
@@ -161,9 +169,22 @@ class Modal extends React.Component<Props> {
     this._identifier = uniqueModalIdentifier++;
   }
 
+  componentDidMount() {
+    if (ModalEventEmitter) {
+      this._eventSubscription = ModalEventEmitter.addListener(
+        'modalDismissed',
+        event => {
+          if (event.modalID === this._identifier && this.props.onDismiss) {
+            this.props.onDismiss();
+          }
+        },
+      );
+    }
+  }
+
   componentWillUnmount() {
-    if (this.props.onDismiss != null) {
-      this.props.onDismiss();
+    if (this._eventSubscription) {
+      this._eventSubscription.remove();
     }
   }
 

Libraries/Modal/RCTModalHostViewNativeComponent.js

@@ -15,6 +15,7 @@ import type {HostComponent} from '../Renderer/shims/ReactNativeTypes';
 import type {
   WithDefault,
   DirectEventHandler,
+  BubblingEventHandler,
   Int32,
 } from '../Types/CodegenTypes';
 
@@ -86,6 +87,14 @@ type NativeProps = $ReadOnly<{|
    */
   onShow?: ?DirectEventHandler<null>,
 
+  /**
+   * The `onDismiss` prop allows passing a function that will be called once
+   * the modal has been dismissed.
+   *
+   * See https://reactnative.dev/docs/modal.html#ondismiss
+   */
+  onDismiss?: ?BubblingEventHandler<null>,
+
   /**
    * Deprecated. Use the `animationType` prop instead.
    */

React/Views/RCTModalHostViewManager.m

@@ -10,6 +10,7 @@
 #import "RCTBridge.h"
 #import "RCTModalHostView.h"
 #import "RCTModalHostViewController.h"
+#import "RCTModalManager.h"
 #import "RCTShadowView.h"
 #import "RCTUtils.h"
 
@@ -46,8 +47,6 @@ - (void)insertReactSubview:(id<RCTComponent>)subview atIndex:(NSInteger)atIndex
 
 @interface RCTModalHostViewManager () <RCTModalHostViewInteractor>
 
-@property (nonatomic, copy) dispatch_block_t dismissWaitingBlock;
-
 @end
 
 @implementation RCTModalHostViewManager {
@@ -79,33 +78,25 @@ - (void)presentModalHostView:(RCTModalHostView *)modalHostView
   if (_presentationBlock) {
     _presentationBlock([modalHostView reactViewController], viewController, animated, completionBlock);
   } else {
-    __weak typeof(self) weakself = self;
     [[modalHostView reactViewController] presentViewController:viewController
                                                       animated:animated
-                                                    completion:^{
-                                                      !completionBlock ?: completionBlock();
-                                                      __strong typeof(weakself) strongself = weakself;
-                                                      !strongself.dismissWaitingBlock
-                                                          ?: strongself.dismissWaitingBlock();
-                                                      strongself.dismissWaitingBlock = nil;
-                                                    }];
+                                                    completion:completionBlock];
   }
 }
 
 - (void)dismissModalHostView:(RCTModalHostView *)modalHostView
           withViewController:(RCTModalHostViewController *)viewController
                     animated:(BOOL)animated
 {
+  dispatch_block_t completionBlock = ^{
+    if (modalHostView.identifier) {
+      [[self.bridge moduleForClass:[RCTModalManager class]] modalDismissed:modalHostView.identifier];
+    }
+  };
   if (_dismissalBlock) {
-    _dismissalBlock([modalHostView reactViewController], viewController, animated, nil);
+    _dismissalBlock([modalHostView reactViewController], viewController, animated, completionBlock);
   } else {
-    self.dismissWaitingBlock = ^{
-      [viewController.presentingViewController dismissViewControllerAnimated:animated completion:nil];
-    };
-    if (viewController.presentingViewController) {
-      self.dismissWaitingBlock();
-      self.dismissWaitingBlock = nil;
-    }
+    [viewController.presentingViewController dismissViewControllerAnimated:animated completion:completionBlock];
   }
 }
 

React/Views/RCTModalManager.h

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import <React/RCTBridgeModule.h>
+#import <React/RCTEventEmitter.h>
+
+@interface RCTModalManager : RCTEventEmitter <RCTBridgeModule>
+
+- (void)modalDismissed:(NSNumber *)modalID;
+
+@end

React/Views/RCTModalManager.m

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import "RCTModalManager.h"
+
+@interface RCTModalManager ()
+
+@property BOOL shouldEmit;
+
+@end
+
+@implementation RCTModalManager
+
+RCT_EXPORT_MODULE();
+
+- (NSArray<NSString *> *)supportedEvents
+{
+  return @[ @"modalDismissed" ];
+}
+
+- (void)startObserving
+{
+  _shouldEmit = YES;
+}
+
+- (void)stopObserving
+{
+  _shouldEmit = NO;
+}
+
+- (void)modalDismissed:(NSNumber *)modalID
+{
+  if (_shouldEmit) {
+    [self sendEventWithName:@"modalDismissed" body:@{@"modalID" : modalID}];
+  }
+}
+
+@end

ReactAndroid/src/main/java/com/facebook/react/viewmanagers/jni/react/renderer/components/rncore/EventEmitters.cpp

@@ -129,6 +129,13 @@ void ModalHostViewEventEmitter::onShow(OnShow event) const {
     return payload;
   });
 }
+void ModalHostViewEventEmitter::onDismiss(OnDismiss event) const {
+  dispatchEvent("dismiss", [event=std::move(event)](jsi::Runtime &runtime) {
+    auto payload = jsi::Object(runtime);
+
+    return payload;
+  });
+}
 void ModalHostViewEventEmitter::onOrientationChange(OnOrientationChange event) const {
   dispatchEvent("orientationChange", [event=std::move(event)](jsi::Runtime &runtime) {
     auto payload = jsi::Object(runtime);

ReactAndroid/src/main/java/com/facebook/react/viewmanagers/jni/react/renderer/components/rncore/EventEmitters.h

@@ -196,6 +196,10 @@ class ModalHostViewEventEmitter : public ViewEventEmitter {
 
     };
 
+  struct OnDismiss {
+
+    };
+
   enum class OnOrientationChangeOrientation {
     Portrait,
     Landscape
@@ -216,6 +220,8 @@ class ModalHostViewEventEmitter : public ViewEventEmitter {
 
   void onShow(OnShow value) const;
 
+  void onDismiss(OnDismiss value) const;
+
   void onOrientationChange(OnOrientationChange value) const;
 };