Android

This guide will walk you through setting up the Terra SDK in your Android mobile app! The required steps are:

1. SDK Installation
2. Initialise the SDK
3. Connect to a provider
4. Get data from the provider

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Important!

The Terra Android SDK allows you to access data from Samsung Health and GoogleFit. It also allows you to scan data from Freestyle Libre sensors using NFC.

If you do not need to access any of these providers, there is no need to use this SDK! If you need to access Terra's web API, it is more secure to do so from your server backend and send the desired data to your mobile frontend.

Installation

The Android SDK allows you to connect to Health Connect and extract the data to your backend seamlessly.

Requires Android 28 and above

Health Connect Setup

1. The SDK requires Health Connect to function. Make sure it is installed on your user's devices.
2. In the Health Connect app, give all permissions between the app you wish to read from and Health Connect.
3. Navigate to your project's AndroidManifest.xml file. It is typically located at app/src/main/AndroidManifest.xml from the root directory of your project.
4. In your AndroidManifest.xml include the following under the Activity you wish to display to the user when user wants to see your app's privacy policy:

<intent-filter>
    <action android:name="androidx.health.ACTION_SHOW_PERMISSIONS_RATIONALE" />
</intent-filter>
<intent-filter>
  <action android:name="android.intent.action.VIEW_PERMISSION_USAGE"/>
  <category android:name="android.intent.category.HEALTH_PERMISSIONS"/>
</intent-filter>

5. In your AndroidManifest.xml include the following to the Activity you wish to request permissions for Health Connect from:

 <meta-data
     android:name="health_permissions"
     android:resource="@array/health_permissions" />

6. For example, you could add them to the MainActivity activity so both will run when the user launches your app:

<activity
	android:name=".MainActivity"
    android:exported="true"
    android:label="@string/app_name"
    android:theme="@style/Theme.<YOUR_APP_NAME>">
    	<intent-filter>
        	<action android:name="android.intent.action.MAIN" />
        	<category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
  
        <intent-filter>
        	<action android:name="androidx.health.ACTION_SHOW_PERMISSIONS_RATIONALE" />
        </intent-filter>
  			<intent-filter>
          <action android:name="android.intent.action.VIEW_PERMISSION_USAGE"/>
          <category android:name="android.intent.category.HEALTH_PERMISSIONS"/>
        </intent-filter>
        <meta-data
        	android:name="health_permissions"
            android:resource="@array/health_permissions" />
</activity>

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Going LIVE

Before going LIVE (release), you will need to apply for permissions to access the Health Connect API with Google. Use this application form.

In the form, you will need to specify which data types you intend to read from Health Connect.

For each permission which you are not using, please add the following lines to your AndroidManifest.xml

<uses-permission android:name="android.permission.health.READ_HEART_RATE" tools:remove="true"/>

SDK Installation

1. Open your project in Android Studio.
2. Navigate to your project's build.gradle file located in the root directory of your project.
3. Inside the dependencies section of the build.gradle file, add the following line of code using the appropriate version number. This will add the TerraAndroid SDK as a dependency to your project. You can find the latest version number on Maven Central.

implementation 'co.tryterra:terra-android:{VERSION_NUMBER}'

3. Sync your project with Gradle by clicking on the "Sync Project with Gradle Files" button in the toolbar. This will download the TerraAndroid SDK and make it available to your project.

That's it! You have now successfully added TerraAndroid to your Android project. You can now start using TerraAndroid's features in your app.

Initialise the SDK

First, you will need to initialise a TerraManager client. You can do so as follows:

Terra.instance(devId: String, referenceId: String?, context: Context, completion: (TerraManager, TerraError?) -> Unit)

• devId is found at Dashboard > API > Customise > Developer ID
• referenceId is your user's ID within your app
• context is the Context of your Android Activity
• completion callback should awaited

For example:

import co.tryterra.terra.Terra

var terra: TerraManager
Terra.instance("YOUR DEV ID", "REFERENCE ID", this){manager, error -> 
	terra = manager 
}

Second, get an auth token by requesting one from the Terra endpoint with your devId and apiKey, found on the Terra Dashboard.

• endpoint: https://api.tryterra.co/v2/auth/generateAuthToken
• Your headers are dev-id and x-api-key

Here are a few sample requests.

# this code runs on your backend

import requests

headers = {
  "dev-id": "DEV-ID",
  "x-api-key": "API-KEY"
}

response = requests.post("https://api.tryterra.co/v2/auth/generateAuthToken",
                         headers=headers)

response.json()

// this code runs on your backend

import fetch from 'node-fetch'

const options = {
  method: 'POST',
  headers: {
    'dev-id': 'DEV-ID',
    'x-api-key': 'API-KEY'
  }
};

fetch('https://api.tryterra.co/v2/auth/generateAuthToken', options)
  .then(response => response.json())
  .then(response => console.log(response))
  .catch(err => console.error(err));

We can now connect to providers and get data from them.

Connecting to Google Fit, Samsung and Freestyle Libre

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Currently only Libre 1, Pro/H and Libre 2 (UK) are supported!

Libre 2 US and Libre14Days US are not supported currently.

Third, initiate the connection with: GOOGLE FIT, SAMSUNG or FREESTYLELIBRE using the token from the response above.

terra.initConnection(connection: Connections, 
                     token: String, 
                     context: Context, 
                     customPermissions: Set<CustomPermissions>, 
                     schedulerOn: Boolean, 
                     startIntent: String?, 
                     callback: (Boolean, TerraError?) -> Unit)

• Connections takes GOOGLE, SAMSUNG, FREESTYLE_LIBRE depending on which provider you would like to connect to
• token is generated and passed to the mobile device from your backend
• context is the app context for which you call this function from (usually from a class that extends from Activity types)
• customPermissions Optional (defaults to an empty set) Set. If you want to make a more granular permissions request, you may send us a set of CustomPermissions
• startIntent: Optional (defaults to null) String. It signifies the Activity for which you want to start after a FreeStyleLibre Sensor scan is complete. For example if your package name is (in your AndroidManifest.xml) is co.tryterra.terrademo, and the activity you wish to start after the scan is complete is called MainActivity, then you would insert: co.tryterra.terrademo.MainActivity. N.B This functionality only works if your Intent extends from Activity
• schedulerOn: defaults the background delivery option to true. This will make Terra send new data from the provider to your webhook automatically
• completion: callback with a boolean dictating if the connection succeeds

N.B Running this function automatically brings up permission and login screens! You only need to execute this once per connection

Test Authentication

To ensure a connection is still valid, use the getUserid() method. This function is synchronous and returns the user_id right away or null if none exists.You should occasionally use this method to check the connection.

terra.getUserId(Connections): String?

To deauthenticate this user, you will need to call the deauthenticateUser endpoint of the Terra Web API with the user_id. It is recommended to do this from your server backend, so as not to store your apiKey on the mobile app.

Getting Data

You can now access data from the provider you connected to! If you initialised the connection with schedulerOn as true, Terra will automatically send new data from the app to your webhook, when your app is open.

You can also backfill for historical data using one of the many getter functions. You may set toWebhook to false if you wish for the callback function to return the data payload.

    terra.getBody(
        startDate = Date.from(Instant.ofEpochMilli(startTime)).toInstant().epochSecond,
        endDate = Date.from(Instant.ofEpochMilli(endTime)).toInstant().epochSecond,
        toWebhook = false
    ){bodyData ->
        // Do something with body data
        Log.i(TAG, bodyData.toString())
    }

The other data functions would be : getDaily, getActivity, getSleep, getNutrition. These functions use the same arguments as the getBody function and all of them return a callback with their own data models. The data models are objects that have fields which are exactly the same as we the ones given by our Data Models.

Congratulations! You have received the end of this guide. Checkout the Android SDK reference for more details about any of the functions used in this guide.