Learning React Native, 2nd Edition

Chapter 6. Platform APIs

When building mobile applications, you will naturally want to take advantage of the host platform’s specific APIs. React Native makes it easy to access things like the phone’s camera roll, location, and persistent storage. These platform APIs are made available to React Native through included modules, which provide us with easy-to-use asynchronous JavaScript interfaces to these capabilities.

React Native does not wrap all of its host platform’s functionality by default; some platform APIs will require you to either write your own modules, or use modules written by others in the React Native community. We will cover that process in Chapter 7. The docs are the best place to check if an API is supported.

This chapter covers some of the available platform APIs. For our example, we’ll make some modifications to the weather application from earlier. We’ll add geolocation to the app so that it detects the user’s location automatically. We will also add “memory” to the app so it will remember your previously searched locations. Finally, we’ll use the camera roll to change the background image to one of the user’s photos.

While relevant code snippets will be presented in each section, the full code for the application is included in “The SmarterWeather Application”.

Using Geolocation

For mobile applications, knowing the user’s location is often critical. It allows you to serve the user contextually relevant information. Many mobile applications make extensive ...