Coroutines

app/build.gradle

@@ -73,6 +73,7 @@ dependencies {
     implementation platform('com.google.firebase:firebase-bom:29.0.2')
     implementation 'com.google.firebase:firebase-crashlytics'
     implementation 'com.google.firebase:firebase-analytics'
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-play-services:1.3.9'
     implementation 'androidx.legacy:legacy-support-v4:1.0.0'
     implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.3.1'
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1'

app/src/main/java/com/example/dispatcher/model/network/articles/ArticlesApi.kt

@@ -2,11 +2,11 @@ package com.example.dispatcher.model.network.articles
 
 import com.example.dispatcher.model.ArticlesResponse
 import com.example.dispatcher.model.network.articles.ArticlesApiConstants.END_POINT
-import retrofit2.Call
+import retrofit2.Response
 import retrofit2.http.GET
 import retrofit2.http.QueryMap
 
 interface ArticlesApi {
     @GET(END_POINT)
-    fun getArticles(@QueryMap params: Map<String, String>): Call<ArticlesResponse>
+    fun getArticles(@QueryMap params: Map<String, String>): Response<ArticlesResponse>
 }

app/src/main/java/com/example/dispatcher/model/network/articles/ArticlesApiController.kt

@@ -14,7 +14,7 @@ import com.example.dispatcher.model.network.articles.ArticlesApiConstants.API__E
 import com.example.dispatcher.model.network.articles.ArticlesApiConstants.API__EVERYTHING_TO__KEY
 import com.example.dispatcher.model.network.articles.ArticlesApiConstants.ENDPOINT_EVERYTHING
 import com.example.dispatcher.model.network.manager.ApiController
-import retrofit2.Callback
+import retrofit2.Response
 import java.util.HashMap
 
 class ArticlesApiController: ApiController<ArticlesApi>() {
@@ -26,18 +26,17 @@ class ArticlesApiController: ApiController<ArticlesApi>() {
         return ArticlesApi::class.java
     }
 
-    fun getArticles(callback: Callback<ArticlesResponse>,
-                    q: String? = null,
-                    qInTitle: String? = null,
-                    sources: String? = null,
-                    domains: String? = null,
-                    excludeDomains: String? = null,
-                    from: String? = null,
-                    to: String? = null,
-                    language: String? = null,
-                    sortBy: String? = null,
-                    pageSize: Int? = null,
-                    page: Int? = null) {
+    suspend fun getArticles(q: String? = null,
+                            qInTitle: String? = null,
+                            sources: String? = null,
+                            domains: String? = null,
+                            excludeDomains: String? = null,
+                            from: String? = null,
+                            to: String? = null,
+                            language: String? = null,
+                            sortBy: String? = null,
+                            pageSize: Int? = null,
+                            page: Int? = null): Response<ArticlesResponse> {
         val params: MutableMap<String, String> = HashMap()
         when {
             !q.isNullOrEmpty() -> params[API__EVERYTHING_Q__KEY] = q
@@ -53,6 +52,6 @@ class ArticlesApiController: ApiController<ArticlesApi>() {
             page != null -> params[API__EVERYTHING_PAGE__KEY] = "$page"
         }
 
-        getApi().getArticles(params).enqueue(callback)
+        return getApi().getArticles(params)
     }
 }

app/src/main/java/com/example/dispatcher/model/network/headlines/TopHeadlinesApi.kt

@@ -2,11 +2,11 @@ package com.example.dispatcher.model.network.headlines
 
 import com.example.dispatcher.model.ArticlesResponse
 import com.example.dispatcher.model.network.headlines.TopHeadlinesConstants.END_POINT
-import retrofit2.Call
+import retrofit2.Response
 import retrofit2.http.GET
 import retrofit2.http.QueryMap
 
 interface TopHeadlinesApi {
     @GET(END_POINT)
-    fun getTopArticles(@QueryMap params: Map<String, String>): Call<ArticlesResponse>
+    suspend fun getArticles(@QueryMap params: Map<String, String>): Response<ArticlesResponse>
 }

app/src/main/java/com/example/dispatcher/model/network/headlines/TopHeadlinesApiController.kt

@@ -9,7 +9,7 @@ import com.example.dispatcher.model.network.headlines.TopHeadlinesConstants.API_
 import com.example.dispatcher.model.network.headlines.TopHeadlinesConstants.API__HEADLINES_SOURCES__KEY
 import com.example.dispatcher.model.network.headlines.TopHeadlinesConstants.ENDPOINT_TOP
 import com.example.dispatcher.model.network.manager.ApiController
-import retrofit2.Callback
+import retrofit2.Response
 import java.util.HashMap
 
 class TopHeadlinesApiController: ApiController<TopHeadlinesApi>() {
@@ -21,13 +21,12 @@ class TopHeadlinesApiController: ApiController<TopHeadlinesApi>() {
         return TopHeadlinesApi::class.java
     }
 
-    fun getTopArticles(callback: Callback<ArticlesResponse>,
-                       country: String? = null,
+    suspend fun getTopArticles(country: String? = null,
                        category: String? = null,
                        sources: String? = null,
                        q: String? = null,
                        pageSize: Int? = null,
-                       page: Int? = null){
+                       page: Int? = null): Response<ArticlesResponse> {
         val params: MutableMap<String, String> = HashMap()
         when {
             !country.isNullOrEmpty() -> params[API__HEADLINES_COUNTRY__KEY] = country
@@ -38,6 +37,6 @@ class TopHeadlinesApiController: ApiController<TopHeadlinesApi>() {
             page != null -> params[API__HEADLINES_PAGE__KEY] = "$page"
         }
 
-        getApi().getTopArticles(params).enqueue(callback)
+        return getApi().getArticles(params)
     }
 }

app/src/main/java/com/example/dispatcher/viewmodel/DashboardViewModel.kt

@@ -2,12 +2,12 @@ package com.example.dispatcher.viewmodel
 
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
 import com.example.dispatcher.model.Article
-import com.example.dispatcher.model.ArticlesResponse
 import com.example.dispatcher.model.network.headlines.TopHeadlinesApiController
-import retrofit2.Call
-import retrofit2.Callback
-import retrofit2.Response
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import java.lang.Exception
 import java.util.*
 import kotlin.collections.ArrayList
 
@@ -19,18 +19,14 @@ class DashboardViewModel : ViewModel() {
     }
 
     private fun getArticles() {
-        TopHeadlinesApiController()
-            .getTopArticles(object: Callback<ArticlesResponse> {
-                override fun onResponse(
-                    call: Call<ArticlesResponse>,
-                    response: Response<ArticlesResponse>) {
-                    if (response.isSuccessful && response.body() != null)
-                        articles.value = response.body()!!.articles
-                }
-
-                override fun onFailure(call: Call<ArticlesResponse>, t: Throwable) {
-                    t.printStackTrace()
-                }
-            }, Locale.getDefault().country)
+        viewModelScope.launch(Dispatchers.IO) {
+            try {
+                val response = TopHeadlinesApiController().getTopArticles(Locale.getDefault().country)
+                if (response.isSuccessful && response.body() != null)
+                    articles.postValue(response.body()!!.articles)
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+        }
     }
 }