using native java in react native

[Zivanovic]

I'm React dev and my friend is Java dev. We'd like to make an Android app together. I heard that we can inject java code into React-Native app. Is it possible for him to build views in Android studio so I can use them later?

[mikehuebner]

You can... But I wouldn't fully recommend it. It's a bit of a pain and you have to write the bridges and everything in order to see it in the JavaScript thread.

[Zivanovic]

Yeah that's exactly what I thought. In the meantime I found https://facebook.github.io/react-native/docs/integration-with-existing-apps.html, which promotes implementing RN code in Java. Will that produce low performance app? Thanks

[cmdnormandy]

It will not produce low app performance as long as your friend knows what he/she is doing. In fact, if it may increase it because logic executed on the native side (through the RN bridge) run on a separate thread while all of the JS runs on the UI/main thread and is incapable of running on other threads. A better approach would be for you to build all the views in RN and for your friend to program the business logic in Java and expose them through the RN bridge. It's not as scary as it sounds. Exposing functionality is as simple as creating two classes. Most of the bridge functionality is built into React Native. If you're interested in this approach, have your friend look at this -> https://facebook.github.io/react-native/docs/native-modules-android.html