@hiram112. React native works in a 'conceptually' similar way as wxWidgets (if you are familiar with with that). It uses platform's native APIs. It does not rely on a web browser on your mobile device. The integration is also not just for widgets, but underneath it abstracts out Image, network api, basic storage/preference primitives, screen rotation, etc.
For the things that it does not abstract, it let's you write a native module, that you register with RN runtime, and then the APIs for your native module will be avialable to your RN java script code.
There is an active opensource ecosystem of RN-modules that you can leverage, that will work on Android and IoS , abstracting the platform specific things that RN does not do yet themselves. Everything from non trivial camera interactions to bluetooth specific things. Eg
For the things that it does not abstract, it let's you write a native module, that you register with RN runtime, and then the APIs for your native module will be avialable to your RN java script code.
There is an active opensource ecosystem of RN-modules that you can leverage, that will work on Android and IoS , abstracting the platform specific things that RN does not do yet themselves. Everything from non trivial camera interactions to bluetooth specific things. Eg
https://github.com/Polidea/react-native-ble-plx