Improve error handling

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

@@ -1,13 +1,11 @@
 package com.task.data
 
-import com.task.data.error.Error
-
 // A generic class that contains data and status about loading this data.
 sealed class Resource<T>(
         val data: T? = null,
-        val error: Error? = null
+        val errorCode: Int? = null
 ) {
     class Success<T>(data: T) : Resource<T>(data)
     class Loading<T>(data: T? = null) : Resource<T>(data)
-    class DataError<T>(error: Error) : Resource<T>(null, error)
+    class DataError<T>(errorCode: Int) : Resource<T>(null, errorCode)
 }

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

@@ -2,10 +2,8 @@ package com.task.data.remote
 
 import com.task.App
 import com.task.data.Resource
-import com.task.data.error.Error
 import com.task.data.error.Error.Companion.NETWORK_ERROR
 import com.task.data.error.Error.Companion.NO_INTERNET_CONNECTION
-import com.task.data.error.factory.ErrorFactoryImpl
 import com.task.data.remote.dto.NewsModel
 import com.task.data.remote.service.NewsService
 import com.task.utils.Constants
@@ -20,7 +18,7 @@ import javax.inject.Inject
  */
 
 class RemoteRepository @Inject
-constructor(private val serviceGenerator: ServiceGenerator, private val errors: ErrorFactoryImpl) : RemoteSource {
+constructor(private val serviceGenerator: ServiceGenerator) : RemoteSource {
 
     override suspend fun requestNews(): Resource<NewsModel> {
         val newsService = serviceGenerator.createService(NewsService::class.java, Constants.BASE_URL)
@@ -29,25 +27,25 @@ constructor(private val serviceGenerator: ServiceGenerator, private val errors:
                 Resource.Success(data = response)
             }
             else -> {
-                Resource.DataError(error = response as Error)
+                Resource.DataError(errorCode = response as Int)
             }
         }
     }
 
     private suspend fun processCall(responseCall: suspend () -> Response<*>): Any? {
         if (!isConnected(App.context)) {
-            return errors.getError(NO_INTERNET_CONNECTION)
+            return NO_INTERNET_CONNECTION
         }
         return try {
             val response = responseCall.invoke()
             val responseCode = response.code()
             if (response.isSuccessful) {
                 response.body()
             } else {
-                errors.getError(responseCode)
+                responseCode
             }
         } catch (e: IOException) {
-            errors.getError(NETWORK_ERROR)
+            NETWORK_ERROR
         }
     }
 }

app/src/main/java/com/task/di/ErrorModule.kt

@@ -1,19 +1,19 @@
 package com.task.di
 
-import com.task.data.error.factory.ErrorFactory
-import com.task.data.error.factory.ErrorFactoryImpl
 import com.task.data.error.mapper.ErrorMapper
 import com.task.data.error.mapper.ErrorMapperInterface
+import com.task.usecase.errors.ErrorFactory
+import com.task.usecase.errors.ErrorManager
 import dagger.Binds
 import dagger.Module
 import javax.inject.Singleton
 
-// Tells Dagger this is a Dagger module
+// with @Module we Telling Dagger that, this is a Dagger module
 @Module
 abstract class ErrorModule {
     @Binds
     @Singleton
-    abstract fun provideErrorFactoryImpl(errorFactoryImpl: ErrorFactoryImpl): ErrorFactory
+    abstract fun provideErrorFactoryImpl(errorManager: ErrorManager): ErrorFactory
 
     @Binds
     @Singleton

app/src/main/java/com/task/ui/base/BaseViewModel.kt

@@ -1,11 +1,18 @@
 package com.task.ui.base
 
 import androidx.lifecycle.ViewModel
+import com.task.usecase.errors.ErrorManager
 
 
 /**
  * Created by AhmedEltaher on 5/12/2016
  */
 
 
-abstract class BaseViewModel: ViewModel()
+abstract class BaseViewModel : ViewModel() {
+    /**Inject Singlton ErrorManager
+     * Use this errorManager to get the Errors
+     */
+    abstract val errorManager: ErrorManager
+
+}

app/src/main/java/com/task/ui/component/details/DetailsViewModel.kt

@@ -1,15 +1,19 @@
 package com.task.ui.component.details
 
 import androidx.lifecycle.MutableLiveData
+import com.task.data.error.mapper.ErrorMapper
 import com.task.data.remote.dto.NewsItem
 import com.task.ui.base.BaseViewModel
+import com.task.usecase.errors.ErrorManager
 import javax.inject.Inject
 
 /**
  * Created by AhmedEltaher on 11/12/16.
  */
 
 class DetailsViewModel @Inject
-constructor() : BaseViewModel(){
+constructor() : BaseViewModel() {
     var newsItem: MutableLiveData<NewsItem> = MutableLiveData()
+    override val errorManager: ErrorManager
+        get() = ErrorManager(ErrorMapper())
 }

app/src/main/java/com/task/ui/component/news/NewsListActivity.kt

@@ -20,7 +20,6 @@ import com.task.utils.*
 import kotlinx.android.synthetic.main.home_activity.*
 import kotlinx.android.synthetic.main.toolbar.*
 import org.jetbrains.anko.intentFor
-import org.jetbrains.anko.toast
 import javax.inject.Inject
 
 /**
@@ -82,6 +81,10 @@ class NewsListActivity : BaseActivity() {
         rl_news_list.setupSnackbar(this, event, Snackbar.LENGTH_LONG)
     }
 
+    private fun observeToast(event: LiveData<Event<Any>>) {
+        rl_news_list.showToast(this, event, Snackbar.LENGTH_LONG)
+    }
+
     private fun showSearchError() {
         newsListViewModel.showSnackbarMessage(R.string.search_error)
     }
@@ -116,7 +119,7 @@ class NewsListActivity : BaseActivity() {
             is Resource.Success -> newsModel.data?.let { bindListData(newsModel = it) }
             is Resource.DataError -> {
                 showDataView(false)
-                toast("${newsModel.error?.description}")
+                newsModel.errorCode?.let { newsListViewModel.showToastMessage(it) }
             }
         }
 
@@ -128,5 +131,7 @@ class NewsListActivity : BaseActivity() {
         observe(newsListViewModel.noSearchFound, ::noSearchResult)
         observeEvent(newsListViewModel.openNewsDetails, ::navigateToDetailsScreen)
         observeSnackBarMessages(newsListViewModel.showSnackBar)
+        observeToast(newsListViewModel.showToast)
+
     }
 }

app/src/main/java/com/task/ui/component/news/NewsListViewModel.kt

@@ -4,10 +4,12 @@ import androidx.annotation.StringRes
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import com.task.data.Resource
+import com.task.data.error.mapper.ErrorMapper
 import com.task.data.remote.dto.NewsItem
 import com.task.data.remote.dto.NewsModel
 import com.task.ui.base.BaseViewModel
 import com.task.usecase.NewsUseCase
+import com.task.usecase.errors.ErrorManager
 import com.task.utils.Event
 import javax.inject.Inject
 
@@ -18,6 +20,9 @@ import javax.inject.Inject
 class NewsListViewModel @Inject
 constructor(private val newsDataUseCase: NewsUseCase) : BaseViewModel() {
 
+    override val errorManager: ErrorManager
+        get() = ErrorManager(ErrorMapper())
+
     /**
      * Data --> LiveData, Exposed as LiveData, Locally in viewModel as MutableLiveData
      */
@@ -30,16 +35,19 @@ constructor(private val newsDataUseCase: NewsUseCase) : BaseViewModel() {
     val noSearchFound: LiveData<Unit> get() = noSearchFoundPrivate
 
     /**
-     * UI actions as event, user action is  single one time event, Shouldn't be multiple time consumption
+     * UI actions as event, user action is single one time event, Shouldn't be multiple time consumption
      */
     private val openNewsDetailsPrivate = MutableLiveData<Event<NewsItem>>()
     val openNewsDetails: LiveData<Event<NewsItem>> get() = openNewsDetailsPrivate
 
+    /**
+     * Error handling as UI
+     */
     private val showSnackBarPrivate = MutableLiveData<Event<Int>>()
     val showSnackBar: LiveData<Event<Int>> get() = showSnackBarPrivate
 
-    private val showToastPrivate = MutableLiveData<Event<Int>>()
-    val showToast: LiveData<Event<Int>> get() = showToastPrivate
+    private val showToastPrivate = MutableLiveData<Event<Any>>()
+    val showToast: LiveData<Event<Any>> get() = showToastPrivate
 
 
     fun getNews() {
@@ -54,8 +62,9 @@ constructor(private val newsDataUseCase: NewsUseCase) : BaseViewModel() {
         showSnackBarPrivate.value = Event(message)
     }
 
-    fun showToastMessage(@StringRes message: Int) {
-        showToastPrivate.value = Event(message)
+    fun showToastMessage(errorCode: Int) {
+        val error = errorManager.getError(errorCode)
+        showToastPrivate.value = Event(error.description)
     }
 
     fun onSearchClick(newsTitle: String) {

app/src/main/java/com/task/ui/component/splash/SplashViewModel.kt

@@ -1,11 +1,16 @@
 package com.task.ui.component.splash
 
+import com.task.data.error.mapper.ErrorMapper
 import com.task.ui.base.BaseViewModel
+import com.task.usecase.errors.ErrorManager
 import javax.inject.Inject
 
 /**
  * Created by AhmedEltaher on 5/12/2016
  */
 
 class SplashViewModel @Inject
-constructor() : BaseViewModel()
+constructor() : BaseViewModel(){
+    override val errorManager: ErrorManager
+        get() = ErrorManager(ErrorMapper())
+}

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

@@ -4,8 +4,10 @@ import androidx.lifecycle.MutableLiveData
 import com.task.data.DataSource
 import com.task.data.Resource
 import com.task.data.error.Error
+import com.task.data.error.Error.Companion.NETWORK_ERROR
 import com.task.data.remote.dto.NewsItem
 import com.task.data.remote.dto.NewsModel
+import com.task.usecase.errors.ErrorManager
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.launch
 import javax.inject.Inject
@@ -30,7 +32,7 @@ constructor(private val dataRepository: DataSource, override val coroutineContex
                 serviceResponse = dataRepository.requestNews()
                 newsMutableLiveData.postValue(serviceResponse)
             } catch (e: Exception) {
-                newsMutableLiveData.postValue(Resource.DataError(Error(e)))
+                newsMutableLiveData.postValue(Resource.DataError(NETWORK_ERROR))
             }
         }
     }

app/src/main/java/com/task/data/error/factory/ErrorFactory.kt → app/src/main/java/com/task/usecase/errors/ErrorFactory.kt

@@ -1,4 +1,4 @@
-package com.task.data.error.factory
+package com.task.usecase.errors
 
 import com.task.data.error.Error
 

app/src/main/java/com/task/data/error/factory/ErrorFactoryImpl.kt → app/src/main/java/com/task/usecase/errors/ErrorManager.kt

@@ -1,4 +1,4 @@
-package com.task.data.error.factory
+package com.task.usecase.errors
 
 import com.task.data.error.Error
 import com.task.data.error.mapper.ErrorMapper
@@ -8,7 +8,7 @@ import javax.inject.Inject
  * Created by AhmedEltaher on 5/12/2016
  */
 
-class ErrorFactoryImpl @Inject constructor(private val errorMapper: ErrorMapper) : ErrorFactory {
+class ErrorManager @Inject constructor(private val errorMapper: ErrorMapper) : ErrorFactory {
     override fun getError(errorCode: Int): Error {
         return Error(code = errorCode, description = errorMapper.errorsMap.getValue(errorCode))
     }

app/src/main/java/com/task/utils/ViewExt.kt

@@ -4,6 +4,7 @@ import android.app.Service
 import android.view.View
 import android.view.inputmethod.InputMethodManager
 import android.widget.ImageView
+import android.widget.Toast
 import androidx.annotation.DrawableRes
 import androidx.appcompat.widget.AppCompatEditText
 import androidx.appcompat.widget.AppCompatTextView
@@ -73,6 +74,24 @@ fun View.setupSnackbar(
     })
 }
 
+fun View.showToast(
+        lifecycleOwner: LifecycleOwner,
+        snackbarEvent: LiveData<Event<Any>>,
+        timeLength: Int
+) {
+
+    snackbarEvent.observe(lifecycleOwner, Observer { event ->
+        event.getContentIfNotHandled()?.let {
+            when (it) {
+                is String -> Toast.makeText(context, it, timeLength).show()
+                is Int -> Toast.makeText(context, context.getString(it), timeLength).show()
+                else -> {
+                }
+            }
+        }
+    })
+}
+
 fun ImageView.loadImage(@DrawableRes resId: Int) = Picasso.get().load(resId).into(this)
 fun ImageView.loadImage(url: String) = Picasso.get().load(url).placeholder(R.drawable.news).error(R.drawable.news).into(this)