Kotlin Retrofit Not Making Network Calls Solution

If your Kotlin app using Retrofit isn’t making any network calls, it can be frustrating, especially during debugging or while building production-level apps. This issue often arises due to misconfigurations in Retrofit setup, incorrect coroutine usage, or missing permissions in AndroidManifest.xml. Here’s a step-by-step guide to fix it with a working example.

Step 1: Add Required Dependencies

Make sure you’ve added the correct Retrofit and converter dependencies in your build.gradle file:

implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.1'

Step 2: Add Internet Permission

Update your AndroidManifest.xml:

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

Step 3: Create Data Model

data class Post(
    val userId: Int,
    val id: Int,
    val title: String,
    val body: String
)

Step 4: Define Retrofit API Interface

import retrofit2.http.GET
import retrofit2.Response

interface ApiService {
    @GET("posts")
    suspend fun getPosts(): Response<List<Post>>
}

Step 5: Build Retrofit Instance

import retrofit2.Retrofit
import retrofit2.converter.gson.GsonConverterFactory

object RetrofitClient {
    private const val BASE_URL = "https://jsonplaceholder.typicode.com/"

    val instance: ApiService by lazy {
        Retrofit.Builder()
            .baseUrl(BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .build()
            .create(ApiService::class.java)
    }
}

Step 6: Call API in ViewModel

import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.launch

class MainViewModel : ViewModel() {

    fun fetchPosts() {
        viewModelScope.launch {
            try {
                val response = RetrofitClient.instance.getPosts()
                if (response.isSuccessful) {
                    val posts = response.body()
                    println("Success: ${posts?.size} posts loaded")
                } else {
                    println("Error: ${response.code()}")
                }
            } catch (e: Exception) {
                println("Exception: ${e.message}")
            }
        }
    }
}

Step 7: Trigger the Network Call in Activity

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.viewModels

class MainActivity : ComponentActivity() {

    private val viewModel: MainViewModel by viewModels()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        viewModel.fetchPosts()
    }
}

Common Mistakes That Cause No Network Calls:

• Missing INTERNET permission.
• Not using suspend functions in Retrofit interface.
• Network call not triggered in ViewModelScope.
• Forgetting to set correct baseUrl.
• Network on main thread (if not using coroutines or proper async calls).

For further reading on common pitfalls, you can check out this useful Retrofit guide.