Android (Kotlin)

A minimal Kotlin integration using OkHttp (included in most Android projects).

Setup

Add OkHttp to your build.gradle.kts:

implementation("com.squareup.okhttp3:okhttp:4.12.0")

VoltaClient

import okhttp3.*
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.RequestBody.Companion.toRequestBody
import org.json.JSONObject

class VoltaClient(
    private val apiUrl: String,
    private val apiKey: String,
    private val layoutId: String
) {
    private val http = OkHttpClient()
    private val json = "application/json".toMediaType()
    private var token: String? = null

    // Step 1: Discover controls
    fun getLayoutInfo(): JSONObject {
        val request = Request.Builder()
            .url("$apiUrl/layout/$layoutId")
            .header("x-api-key", apiKey)
            .build()
        val response = http.newCall(request).execute()
        return JSONObject(response.body!!.string())
    }

    // Step 2: Get a token
    fun connect() {
        val body = JSONObject().put("layoutId", layoutId)
            .toString().toRequestBody(json)
        val request = Request.Builder()
            .url("$apiUrl/token")
            .header("x-api-key", apiKey)
            .post(body)
            .build()
        val response = http.newCall(request).execute()
        token = JSONObject(response.body!!.string()).getString("token")
    }

    // Step 3: Send actions
    fun sendAction(lid: Int, type: String, value: Any? = null) {
        val body = JSONObject().apply {
            put("layoutId", layoutId)
            put("lid", lid)
            put("type", type)
            if (value != null) put("value", value)
        }.toString().toRequestBody(json)

        val request = Request.Builder()
            .url("$apiUrl/action")
            .header("Authorization", "Bearer ${token!!}")
            .post(body)
            .build()
        http.newCall(request).execute()
    }

    // Convenience methods
    fun sendButton(lid: Int) = sendAction(lid, "Button")
    fun sendSlider(lid: Int, value: Float) = sendAction(lid, "Slider", value)
    fun sendToggle(lid: Int, value: Boolean) = sendAction(lid, "Toggle", value)
    fun sendIndex(lid: Int, value: Int) = sendAction(lid, "Index", value)
}

Usage

// Run on a background thread (e.g. with coroutines)
val client = VoltaClient(
    apiUrl = "https://your-api-url.execute-api.eu-west-2.amazonaws.com",
    apiKey = "your-api-key",
    layoutId = "your-layout-id"
)

client.connect()
val layout = client.getLayoutInfo()

// Send a button press
client.sendButton(lid = 1)

// Send a slider value
client.sendSlider(lid = 2, value = 0.75f)