implement data status

app/src/main/java/com/task/data/DataRepository.kt

@@ -2,7 +2,6 @@ package com.task.data
 
 import com.task.data.local.LocalRepository
 import com.task.data.remote.RemoteRepository
-import com.task.data.remote.Data
 import javax.inject.Inject
 
 
@@ -13,7 +12,7 @@ import javax.inject.Inject
 class DataRepository @Inject
 constructor(private val remoteRepository: RemoteRepository, private val localRepository: LocalRepository) : DataSource {
 
-    override  fun requestNews(): Data? {
+    override  fun requestNews(): DataStatus {
         return remoteRepository.requestNews()
     }
 }

app/src/main/java/com/task/data/DataSource.kt

@@ -1,11 +1,9 @@
 package com.task.data
 
-import com.task.data.remote.Data
-
 /**
  * Created by ahmedeltaher on 3/23/17.
  */
 
 interface DataSource {
-    fun requestNews(): Data?
+    fun requestNews(): DataStatus
 }

app/src/main/java/com/task/data/DataStatus.kt

@@ -0,0 +1,10 @@
+package com.task.data
+
+import com.task.data.remote.Data
+import com.task.data.remote.Error
+
+sealed class DataStatus {
+    object LoadingState : DataStatus()
+    class FailureState(val error: Error) : DataStatus()
+    class SuccessState(val data: Data) : DataStatus()
+}

app/src/main/java/com/task/data/Resource.kt

@@ -0,0 +1,11 @@
+package com.task.data
+
+// A generic class that contains data and status about loading this data.
+sealed class Resource<T>(
+        val data: T? = null,
+        val message: String? = null
+) {
+    class Success<T>(data: T) : Resource<T>(data)
+    class Loading<T>(data: T? = null) : Resource<T>(data)
+    class Error<T>(message: String, data: T? = null) : Resource<T>(data, message)
+}

app/src/main/java/com/task/data/remote/RemoteRepository.kt

@@ -1,6 +1,7 @@
 package com.task.data.remote
 
 import com.task.App
+import com.task.data.DataStatus
 import com.task.data.remote.Error.Companion.NETWORK_ERROR
 import com.task.data.remote.service.NewsService
 import com.task.utils.Constants
@@ -18,36 +19,36 @@ import javax.inject.Inject
 class RemoteRepository @Inject
 constructor(private val serviceGenerator: ServiceGenerator) : RemoteSource {
 
-    override  fun requestNews(): Data? {
+    override fun requestNews(): DataStatus {
         return if (!isConnected(App.context)) {
-            Data(Error(code = -1, description = NETWORK_ERROR))
+            DataStatus.FailureState(Error(code = -1, description = NETWORK_ERROR))
         } else {
             val newsService = serviceGenerator.createService(NewsService::class.java, Constants.BASE_URL)
             processCall(newsService.fetchNews(), false)
         }
     }
 
-    private fun processCall(call: Call<*>, isVoid: Boolean): Data {
+    private fun processCall(call: Call<*>, isVoid: Boolean): DataStatus {
         if (!isConnected(App.context)) {
-            return Data(Error())
+            return DataStatus.FailureState(Error())
         }
         try {
             val response = call.execute()
-                    ?: return Data(Error(NETWORK_ERROR, ERROR_UNDEFINED))
+                    ?: return DataStatus.FailureState(Error(NETWORK_ERROR, ERROR_UNDEFINED))
             val responseCode = response.code()
             /**
              * isVoid is for APIs which reply only with code without any body, such as some Apis
              * reply with 200 or 401....
              */
             return if (response.isSuccessful) {
                 val apiResponse: Any? = if (isVoid) null else response.body()
-                Data(responseCode, apiResponse)
+                DataStatus.SuccessState(Data(responseCode, apiResponse))
             } else {
                 val serviceError = Error(response.message(), responseCode)
-                Data(serviceError)
+                DataStatus.FailureState(serviceError)
             }
         } catch (e: IOException) {
-            return Data(Error(NETWORK_ERROR, ERROR_UNDEFINED))
+            return DataStatus.FailureState(Error(NETWORK_ERROR, ERROR_UNDEFINED))
         }
 
     }

app/src/main/java/com/task/data/remote/RemoteSource.kt

@@ -1,9 +1,11 @@
 package com.task.data.remote
 
+import com.task.data.DataStatus
+
 /**
  * Created by ahmedEltaher on 3/23/17.
  */
 
 internal interface RemoteSource {
-    fun requestNews(): Data?
+    fun requestNews(): DataStatus
 }

app/src/main/java/com/task/usecase/NewsUseCase.kt

@@ -1,9 +1,10 @@
 package com.task.usecase
 
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
 import com.task.data.DataSource
-import com.task.data.remote.Data
+import com.task.data.DataStatus
 import com.task.data.remote.Error
-import com.task.data.remote.Error.Companion.INTERNAL_SERVER_ERROR
 import com.task.data.remote.dto.NewsItem
 import com.task.data.remote.dto.NewsModel
 import com.task.ui.base.listeners.BaseCallback
@@ -21,17 +22,33 @@ import kotlin.coroutines.CoroutineContext
 
 class NewsUseCase @Inject
 constructor(private val dataRepository: DataSource, override val coroutineContext: CoroutineContext) : UseCase, CoroutineScope {
+    var error: LiveData<Error> = MutableLiveData<Error>()
+
+    private val newsMutableLiveData = MutableLiveData<NewsModel>()
+    override val newsLiveData: LiveData<NewsModel> = newsMutableLiveData
 
     override fun getNews(callback: BaseCallback) {
         launch {
             try {
-                val serviceResponse: Data? = withContext(Dispatchers.IO) { dataRepository.requestNews() }
-                if (serviceResponse?.code == Error.SUCCESS_CODE) {
-                    val data = serviceResponse.data
-                    callback.onSuccess(data as NewsModel)
-                } else {
-                    callback.onFail(serviceResponse?.error ?: Error(code = INTERNAL_SERVER_ERROR))
+                val serviceResponse: DataStatus = withContext(Dispatchers.IO) { dataRepository.requestNews() }
+                when (serviceResponse) {
+                    is DataStatus.LoadingState -> {
+                    }
+                    is DataStatus.SuccessState -> {
+                        callback.onSuccess(serviceResponse.data.data as NewsModel)
+//                        newsMutableLiveData.postValue(serviceResponse.data.data as NewsModel)
+                    }
+                    is DataStatus.FailureState -> {
+                        callback.onFail(serviceResponse.error)
+                    }
                 }
+
+//                if (serviceResponse?.code == Error.SUCCESS_CODE) {
+//                    val data = serviceResponse.data
+//                    callback.onSuccess(data as NewsModel)
+//                } else {
+//                    callback.onFail(serviceResponse?.error ?: Error(code = INTERNAL_SERVER_ERROR))
+//                }
             } catch (e: Exception) {
                 callback.onFail(Error(e))
             }

app/src/main/java/com/task/usecase/UseCase.kt

@@ -1,6 +1,8 @@
 package com.task.usecase
 
+import androidx.lifecycle.LiveData
 import com.task.data.remote.dto.NewsItem
+import com.task.data.remote.dto.NewsModel
 import com.task.ui.base.listeners.BaseCallback
 
 /**
@@ -11,4 +13,5 @@ interface UseCase {
     fun getNews(callback: BaseCallback)
 
     fun searchByTitle(news: List<NewsItem>, keyWord: String): NewsItem?
+    val newsLiveData: LiveData<NewsModel>
 }