How to make an API request in Kotlin?

Once you have set your Android Studio to use Kotlin is pretty simple to do a REST call, and it’s pretty much the same logic as with Java.

Here’s an example of a REST call with OkHttp:

build.gradle

dependencies {
    //...
    implementation 'com.squareup.okhttp3:okhttp:3.8.1'
}

AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />

MainActivity.kt

class MainActivity : AppCompatActivity() {

    private val client = OkHttpClient()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        run("https://api.github.com/users/Evin1-/repos")
    }

    fun run(url: String) {
        val request = Request.Builder()
                .url(url)
                .build()

        client.newCall(request).enqueue(object : Callback {
            override fun onFailure(call: Call, e: IOException) {}
            override fun onResponse(call: Call, response: Response) = println(response.body()?.string())
        })
    }
}

Below are a few more complicated examples with other libraries:

• Network request in Kotlin with Retrofit
• Network request in Kotlin with Retrofit and coroutines
• Network request in Kotlin with Dagger, RxJava, Retrofit in MVP