React-Native iOS - How can I navigate to a non-React-Native view (native iOS view controller) from a React-Native view with a button press?

Question

The RN doco and other examples show how to launch a React-Native view from a native iOS view controller, but not the other way around. Can someone explain how I can do this

Answer 1

An update to this answer with Swift 5. Thanks to

https://github.com/facebook/react-native/issues/1148#issuecomment-102008892

https://stackoverflow.com/a/46007680/7325179 - answer by MStrapko

https://codersera.com/blog/react-native-bridge-for-ios/?unapproved=2851&moderation-hash=77e42524b246d2fda0f763a496156db5#comment-2851 - an elaborate explanation and tutorial by William Dawson

Getting into the Solution:

In AppDelegate.swift

import Foundation
import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
  var window: UIWindow?
  var bridge: RCTBridge!
  
  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    let jsCodeLocation: URL
    
    jsCodeLocation = RCTBundleURLProvider.sharedSettings().jsBundleURL(forBundleRoot: "index.js", fallbackResource:nil)
    let rootView = RCTRootView(bundleURL: jsCodeLocation, moduleName: "RNModuleName", initialProperties: nil, launchOptions: launchOptions)
    
    self.window = UIWindow(frame: UIScreen.main.bounds)
    let reactNativeViewController = UIViewController()
    reactNativeViewController.view = rootView
    let reactNavigationController = UINavigationController(rootViewController: reactNativeViewController)
    self.window?.rootViewController = reactNavigationController
    self.window?.makeKeyAndVisible()
    
    return true
  }
//  func goToReactNative() {
//    window?.rootViewController?.dismiss(animated: true)
//  }
  func goNativeStoryboard() {
    DispatchQueue.main.async {
      let vc = UIStoryboard(name: "Main", bundle: nil).instantiateInitialViewController()
      if let vc = vc {
        (self.window?.rootViewController as? UINavigationController)?.pushViewController(vc, animated: true)
      }
    }
  }
}

YourViewController.swift

Your regular code

YourApp-Bridging-Header. Please note there are some extra headers as well, that you might not need.

#import "React/RCTBridgeModule.h"
#import "React/RCTBridge.h"
#import "React/RCTEventDispatcher.h"
#import "React/RCTRootView.h"
#import "React/RCTUtils.h"
#import "React/RCTConvert.h"
#import "React/RCTBundleURLProvider.h"
#import "RCTViewManager.h"
#import "React/RCTEventEmitter.h"

ConnectingFile.swift

@objc(Connect)
class Connect: NSObject {
  @objc func goToNative() -> Void {
    DispatchQueue.main.async {
      if let appDelegate = UIApplication.shared.delegate as? AppDelegate {
        appDelegate.goNativeStoryboard()
      }
    }
  }
}

Connect.m

#import "React/RCTViewManager.h"
@interface RCT_EXTERN_MODULE(Connect, RCTViewManager)
RCT_EXTERN_METHOD(goToNative)

@end

ReactNativeFile.js

import React, { Component } from 'react';
import { StyleSheet, View, NativeModules, Text, TouchableOpacity } from 'react-native';
const { Connect } = NativeModules;
export default class Feed extends Component {
  constructor(props) {
    super(props)
    this.done = false;
  }
  _changeView() {
    this.done = true;
    Connect.goToNative()
  }
  render() {
    return (
      <View style={styles.container}>
        <TouchableOpacity onPress={() => this._changeView()}>
          <Text color="#336699">
            Press to Change to Native View
            </Text>
        </TouchableOpacity>
      </View>
    );
  }
}
const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: 'pink',
    alignItems: 'center',
    justifyContent: 'center',
  }
});

That was it, it worked for me, hope it works for you as well. Thanks again to all the sources of references.

Answer 2

I was able to figure this out. In my case, I am using an Obj-C base project (which is the RN default) with my own Swift native view controller. My solution is here in case this comes up for anyone else:

Simply put, the answer is to use an RCTBridge module to allow the RN JavaScript to call a native iOS method.

Here is an outline of the components, followed by the implementation:

1. AppDelegate.h/.m - Initialize the RN JavaScript index file for the initial RN view, also setup a method to swap the root view controller to a native view controller (this method will be called from the RTCBridge module.

2. MyViewController.swift - A normal UIViewController with a standard implementation.

3. MyProject-Bridging-Header.h - provides Obj-C <-> Swift communication

4. ChangeViewBridge.h/.m - This provides the binding to allow you to call native iOS methods from the RN JavaScript.

5. index.ios.js - Initialize your custom RCTBridge module and call the bound method to switch to your native view with a button press.

AppDelegate.h:

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate> {
  NSDictionary *options;
  UIViewController *viewController;
}

@property (nonatomic, strong) UIWindow *window;

- (void) setInitialViewController;
- (void) goToRegisterView; // called from the RCTBridge module

@end

AppDelegate.m:

#import "AppDelegate.h"
#import <React/RCTBundleURLProvider.h>
#import <React/RCTRootView.h>
#import "FidoTestProject-Swift.h" // Xcode generated import to reference MyViewController.swift from Obj-C

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  options = launchOptions;
  [self setInitialViewController];
  return YES;
}

- (void) setInitialViewController {
  NSURL *jsCodeLocation;

  jsCodeLocation = [NSURL URLWithString:@"http://192.168.208.152:8081/index.ios.bundle?platform=ios&dev=true"];

  RCTRootView *rootView = [[RCTRootView alloc] initWithBundleURL:jsCodeLocation moduleName:@"FidoTestProject" initialProperties:nil launchOptions:options];

  self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
  UIViewController *rootViewController = [UIViewController new];
  rootViewController.view = rootView;
  self.window.rootViewController = rootViewController;

  viewController = rootViewController;

  [self.window makeKeyAndVisible];
}

// this method will be called from the RCTBridge
- (void) goToNativeView {
  NSLog(@"RN binding - Native View - MyViewController.swift - Load From "main" storyboard);
  UIViewController *vc = [UIStoryboard storyboardWithName:@"main" bundle:nil].instantiateInitialViewController;
  self.window.rootViewController = vc;
}

@end

MyViewController.swift:

class RegisterViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        print("MyViewController loaded...")
        // standard view controller will load from RN
    }
}

MyProject-Bridging-Header.h:

@import Foundation;
@import UIKit;
@import CoreLocation;
@import AVFoundation;

#import "React/RCTBridge.h"
#import "React/RCTBridgeModule.h"
#import "React/RCTBundleURLProvider.h"
#import "React/RCTRootView.h"
#import "AppDelegate.h"

ChangeViewBridge.h:

#import <React/RCTBridgeModule.h>

@interface ChangeViewBridge : NSObject <RCTBridgeModule>

- (void) changeToNativeView;

@end

ChangeViewBridge.m:

#import "RegisterBridge.h"
#import "FidoTestProject-Swift.h"
#import "AppDelegate.h"

@implementation ChangeViewBridge

// reference "ChangeViewBridge" module in index.ios.js
RCT_EXPORT_MODULE(ChangeViewBridge);

RCT_EXPORT_METHOD(changeToNativeView) {
  NSLog(@"RN binding - Native View - Loading MyViewController.swift");
  AppDelegate *appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
  [appDelegate goToNativeView];
}

@end

index.ios.js

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 * @flow
 */

'use strict';

import React, { Component } from 'react';
import {
  AppRegistry,
  StyleSheet,
  Alert,
  Text,
  View,
  NativeModules,
  TouchableHighlight
} from 'react-native';

export default class FidoTestProject extends Component {

  constructor(props) {
     super(props)
     this.done = false;
   }

    _changeView() {
      this.done = true;
      this.render();
      NativeModules.ChangeViewBridge.changeToNativeView();
    }

  render() {
    if (!this.done) {
      return (
        <View style={styles.container}>
          <TouchableHighlight onPress={() => this._changeView()}>
            <Text color="#336699">
              Press to Change to Native View
            </Text>
          </TouchableHighlight>
        </View>
      );
    } else {
      return (<View></View>);
    }
  }
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  }
});

AppRegistry.registerComponent('FidoTestProject', () => FidoTestProject);

Answer 3

There is little improvement on this solution.With present solution there is no way to come back to React-Native from iOS. 

If you want to come back again from iOS to React-Native.Do the below

 // AppDelegate.h

    - (void) goToNativeView {
     UIViewController *vc =  [InitialViewController new];// This is your native iOS VC
     UINavigationController* navigationController = [[UINavigationController alloc] initWithRootViewController:vc];

      dispatch_async(dispatch_get_main_queue(), ^{
       // Never do the below, it will be difficult to come back to react-native

       // self.window.rootViewController = navigationController;

        // Do this instead
        [self.window.rootViewController presentViewController:navigationController animated:true completion:NULL];
      });
    }

//InitialViewController.m

    **-Create a button for go back to React-native and on button action dismiss this view controller like below.**

    // Dismiss the VC so controll go back from iOS to react-native
        [self dismissViewControllerAnimated:TRUE completion:nil];