Add Native Code In React Native: Android

For android
Supportive Links :
 https://facebook.github.io/react-native/docs/native-modules-setup
https://facebook.github.io/react-native/docs/native-modules-ios
https://facebook.github.io/react-native/docs/native-modules-android


Native Modules · React Native
https://facebook.github.io




15. First create a separate native code (new Project)
16. Now suppose you have file like : layout file (add this file under layout file), Package file, Module File , & your code files (add these files under main—>java —> com —> bundle name-> paste & update existing file)
 17. Under Module file add @ReactMethod method which will open your Activity on current intent of application ReactMethod method will call from your main react-native project 
Sample code here 
  @ReactMethod
  public void showYoutubePlayer(String urlStr) {

        ReactApplicationContext context = getReactApplicationContext();
        Intent intent = new Intent(context, YoutubeplayerAct.class);
        intent.putExtra("videourl",urlStr);
        context.startActivity(intent);


        // Intent intnt=new Intent(getCurrentActivity(), YoutubeplayerAct.class);
        // intnt.putExtra("videourl",urlStr);
        // startActivity(intnt);
        // Toast.makeText(getReactApplicationContext(), urlStr).show();
  }

18. Add activity under Manifest    android:name="com.reactlibrary.YoutubeplayerAct"
19. Now at last copy your <Name_Of_Lib>  to node_module folder
20. Run react-native link

21. Open your main React -native folder, Open your Controller from where you wanna to open Native module 


In that controller first import <NativeModule> 

Now call the bridge method like this.. 
   var RNYoutubeios = NativeModules.RNYoutubeios;
   RNYoutubeios.showYoutubePlayer(urlID);


-------------
Additional for android 

open Package.json 
under dependencies 
add Lib:     "screenDetector": "file:screenDetector"


under Setting.gradle
add 
include ':screenDetector'
project(':screenDetector').projectDir = new File(rootProject.projectDir, '../node_modules/screenDetector/android') 
react-nativ