Improve UseCase#8

Author: LukasLechnerDev

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/usecases/coroutines/usecase8/AndroidVersionEntity.kt

@@ -7,10 +7,8 @@ import com.lukaslechner.coroutineusecasesonandroid.mock.AndroidVersion
 @Entity(tableName = "androidversions")
 data class AndroidVersionEntity(@PrimaryKey val apiLevel: Int, val name: String)
 
-fun AndroidVersionEntity.mapToUiModel() = AndroidVersion(this.apiLevel, this.name)
-
 fun List<AndroidVersionEntity>.mapToUiModelList() = map {
-    it.mapToUiModel()
+    AndroidVersion(it.apiLevel, it.name)
 }
 
 fun AndroidVersion.mapToEntity() = AndroidVersionEntity(this.apiLevel, this.name)

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/usecases/coroutines/usecase8/RoomAndCoroutinesActivity.kt

@@ -17,16 +17,22 @@ class RoomAndCoroutinesActivity : BaseActivity() {
     override fun getToolbarTitle() = useCase8Description
 
     private val binding by lazy { ActivityQueryfromroomdatabaseBinding.inflate(layoutInflater) }
-    private val viewModel: RoomAndCoroutinesViewModel by viewModels()
+
+    private val viewModel: RoomAndCoroutinesViewModel by viewModels {
+        ViewModelFactory(
+            mockApi(),
+            AndroidVersionDatabase.getInstance(applicationContext).androidVersionDao()
+        )
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(binding.root)
 
         // ugly setter injection of the database
         // could be improved to use constructor injection by using ViewModelFactory
-        viewModel.database =
-            AndroidVersionDatabase.getInstance(applicationContext).androidVersionDao()
+        /*viewModel.database =
+            AndroidVersionDatabase.getInstance(applicationContext).androidVersionDao()*/
         viewModel.uiState().observe(this, Observer { uiState ->
             if (uiState != null) {
                 render(uiState)
@@ -71,12 +77,12 @@ class RoomAndCoroutinesActivity : BaseActivity() {
 
     private fun onSuccess(uiState: UiState.Success) = with(binding) {
         when (uiState.dataSource) {
-            DataSource.Network -> {
+            DataSource.NETWORK -> {
                 progressBarLoadFromNetwork.setGone()
                 imageViewNetworkLoadSuccessOrError.setImageDrawable(getDrawable(R.drawable.ic_check_green_24dp))
                 imageViewNetworkLoadSuccessOrError.setVisible()
             }
-            DataSource.Database -> {
+            DataSource.DATABASE -> {
                 progressBarLoadFromDb.setGone()
                 imageViewDatabaseLoadSuccessOrError.setImageDrawable(getDrawable(R.drawable.ic_check_green_24dp))
                 imageViewDatabaseLoadSuccessOrError.setVisible()
@@ -93,12 +99,12 @@ class RoomAndCoroutinesActivity : BaseActivity() {
 
     private fun onError(uiState: UiState.Error) = with(binding) {
         when (uiState.dataSource) {
-            is DataSource.Network -> {
+            DataSource.NETWORK -> {
                 progressBarLoadFromNetwork.setGone()
                 imageViewNetworkLoadSuccessOrError.setImageDrawable(getDrawable(R.drawable.ic_clear_red_24dp))
                 imageViewNetworkLoadSuccessOrError.setVisible()
             }
-            is DataSource.Database -> {
+            DataSource.DATABASE -> {
                 progressBarLoadFromDb.setGone()
                 imageViewDatabaseLoadSuccessOrError.setImageDrawable(getDrawable(R.drawable.ic_clear_red_24dp))
                 imageViewDatabaseLoadSuccessOrError.setVisible()

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/usecases/coroutines/usecase8/RoomAndCoroutinesViewModel.kt

@@ -6,44 +6,45 @@ import com.lukaslechner.coroutineusecasesonandroid.mock.MockApi
 import kotlinx.coroutines.launch
 
 class RoomAndCoroutinesViewModel(
-    private val api: MockApi = mockApi(),
-    var database: AndroidVersionDao? = null
+    private val api: MockApi,
+    var database: AndroidVersionDao
 ) : BaseViewModel<UiState>() {
 
     fun loadData() {
         uiState.value = UiState.Loading.LoadFromDb
+
         viewModelScope.launch {
 
-            val localVersions = database!!.getAndroidVersions()
+            val localVersions = database.getAndroidVersions()
             if (localVersions.isNotEmpty()) {
                 uiState.value =
-                    UiState.Success(DataSource.Database, localVersions.mapToUiModelList())
+                    UiState.Success(DataSource.DATABASE, localVersions.mapToUiModelList())
             } else {
                 uiState.value =
-                    UiState.Error(DataSource.Database, "Database empty!")
+                    UiState.Error(DataSource.DATABASE, "Database empty!")
             }
 
             uiState.value = UiState.Loading.LoadFromNetwork
             try {
                 val recentVersions = api.getRecentAndroidVersions()
                 for (recentVersion in recentVersions) {
-                    database!!.insert(recentVersion.mapToEntity())
+                    database.insert(recentVersion.mapToEntity())
                 }
-                uiState.value = UiState.Success(DataSource.Network, recentVersions)
+                uiState.value = UiState.Success(DataSource.NETWORK, recentVersions)
             } catch (exception: Exception) {
-                uiState.value = UiState.Error(DataSource.Network, "Network Request failed")
+                uiState.value = UiState.Error(DataSource.NETWORK, "Network Request failed")
             }
         }
     }
 
     fun clearDatabase() {
         viewModelScope.launch {
-            database!!.clear()
+            database.clear()
         }
     }
 }
 
-sealed class DataSource(val name: String) {
-    object Database : DataSource("Database")
-    object Network : DataSource("Network")
+enum class DataSource(val dataSourceName: String) {
+    DATABASE("Database"),
+    NETWORK("Network")
 }

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/usecases/coroutines/usecase8/ViewModelFactory.kt

@@ -0,0 +1,14 @@
+package com.lukaslechner.coroutineusecasesonandroid.usecases.coroutines.usecase8
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import com.lukaslechner.coroutineusecasesonandroid.mock.MockApi
+
+class ViewModelFactory(private val api: MockApi, private val database: AndroidVersionDao) :
+    ViewModelProvider.Factory {
+
+    override fun <T : ViewModel?> create(modelClass: Class<T>): T {
+        return modelClass.getConstructor(MockApi::class.java, AndroidVersionDao::class.java)
+            .newInstance(api, database)
+    }
+}

app/src/main/res/layout/activity_queryfromroomdatabase.xml

@@ -91,6 +91,7 @@
             android:id="@+id/textViewResult"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
+            android:padding="8dp"
             android:textColor="@color/primary_text"
             android:textSize="16sp"
             tools:text="Results" />