tirgei

class MainActivity : AppCompatActivity() {
    ...

    /**
     * Function to fetch posts
     */
    private fun fetchPosts() {
        apiClient.getApiService(this).fetchPosts()
            .enqueue(object : Callback<PostsResponse> {
                override fun onFailure(call: Call<PostsResponse>, t: Throwable) {

tirgei

/**
 * Interface for defining REST request functions
 */
interface ApiService {

    ...

    @GET(Constants.POSTS_URL)
    fun fetchPosts(): Call<PostsResponse>

tirgei

/**
 * Retrofit instance class
 */
class ApiClient {
    private lateinit var apiService: ApiService

    fun getApiService(context: Context): ApiService {

        // Initialize ApiService if not initialized yet
        if (!::apiService.isInitialized) {

tirgei

/**
 * Interceptor to add auth token to requests
 */
class AuthInterceptor(context: Context) : Interceptor {
    private val sessionManager = SessionManager(context)

    override fun intercept(chain: Interceptor.Chain): Response {
        val requestBuilder = chain.request().newBuilder()

        // If token has been saved, add it to the request

tirgei

class MainActivity : AppCompatActivity() {
    
    ...

    /**
     * Function to fetch posts
     */
    private fun fetchPosts() {

        // Pass the token as parameter

tirgei

interface ApiService {

    ...

    @GET(Constants.POSTS_URL)
    fun fetchPosts(@Header("Authorization") token: String): Call<PostsResponse>

}

tirgei

data class PostsResponse (
    @SerializedName("status_code")
    var status: Int,
    
    @SerializedName("message")
    var message: String,
    
    @SerializedName("posts")
    var posts: List<Post>
)

tirgei

data class Post (
    @SerializedName("id")
    var id: Int,
    
    @SerializedName("title")
    var title: String,
    
    @SerializedName("description")
    var description: String,
    

tirgei

class LoginActivity : AppCompatActivity() {
    private lateinit var sessionManager: SessionManager
    private lateinit var apiClient: ApiClient

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

        apiClient = ApiClient()
        sessionManager = SessionManager(this)

tirgei

/**
 * Session manager to save and fetch data from SharedPreferences
 */
class SessionManager (context: Context) {
    private var prefs: SharedPreferences = context.getSharedPreferences(context.getString(R.string.app_name), Context.MODE_PRIVATE)
    
    companion object {
        const val USER_TOKEN = "user_token"
    }