Building a Health Application in React Native

Building a Health Application in React Native

Welcome back to another tutorial! Today we'll build a health application in React Native by integrating our React Native app with health APIs provided by the platform. On iOS, we'll work with Healthkit, and on Android, we'll use Health Connect. We'll use some libraries to get this data into our React Native application and build our health app.

Overview

• What we'll build: A step counter application that looks beautiful on iOS.
• Focus: Step counter feature to keep the project scope manageable (~1-2 hours).

Goals

1. Build a step counter app by getting data from health APIs.
2. Design and build the user interface, focusing on an animated ring using SVG and React Native Reanimated.
3. Render the data from APIs to the screen.

Initialization

• We'll initialize a new project using Expo with the command:

  npx create-expo-app@latest StepCounter -t expo-template-blank-typescript
  

Building the User Interface

1. Text Display: Display steps and distance
   • Steps: e.g., Steps - 1219
   • Distance: e.g., Distance - 0.75 km
2. Animated Ring: Use SVG and React Native Reanimated for creating the animated ring.
3. Styling: Use Flexbox for layout, and use the flex-direction: row style to align elements horizontally.

Adding Functionality

• Extract Steps and Distance to a Separate Component
  • Create a reusable component Value for displaying different values (steps, distance, etc.)
  • Use props to pass the label and value dynamically.

Animation

• React Native Reanimated
  • Use useSharedValue, useAnimatedProps, and withTiming to animate the progress of the ring.
  • Initialize useSharedValue and animate it based on the API data.

Integration with Health APIs

1. iOS: Healthkit
   • Use the react-native-health library to access Healthkit data.
   • Request permissions for steps and distance and fetch this data.
2. Android: Health Connect
   • Use the react-native-health-connect library to access Android Health Connect data.
   • Handle the integration similarly by requesting permissions and fetching data.

Handling Permissions

• Ensure the app has the necessary permissions to read health data both on iOS and Android.

Displaying Data

• Bind the fetched health data to the UI elements (steps, distance, flights climbed).
• Display the fetched data on the ring and update the text values dynamically.

Code Refactoring

• Abstract logic into custom hooks for better manageability.
• Create a custom hook useHealthData to handle the fetching of health data.

Debugging and Testing

• Use device simulators to debug and test the application.
• Test on both iOS and Android to ensure functionality on both platforms.

Final Touches

• Add navigation between dates to view past health data.
• Polished UI to ensure it’s user-friendly and visually appealing.

Learning Outcomes

1. Building cross-platform applications in React Native.
2. Integrating health data APIs (Healthkit for iOS and Health Connect for Android) into a React Native application.
3. Using React Native Reanimated and SVG for creating animated UI components.
4. Modularizing and managing code effectively using hooks and component-based architecture.

References:

• React Native Health
• React Native Health Connect for Android integration.
• Expo for various Expo functionalities.

Note: The tutorial is geared towards building a specific feature (step counter) but the concepts apply broadly to other health-related data points.