call db functions on background thread in ConversationsViewModel (#1040)

* call db functions on background thread in ConversationsViewModel

* use stable library versions

app/build.gradle

@@ -114,7 +114,7 @@ dependencies {
     //room
     implementation 'androidx.room:room-runtime:2.0.0'
     kapt 'androidx.room:room-compiler:2.0.0'
-    implementation 'android.arch.persistence.room:rxjava2:1.1.1'
+    implementation 'androidx.room:room-rxjava2:2.0.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     testImplementation 'junit:junit:4.12'
     implementation "com.google.dagger:dagger:$daggerVersion"
@@ -137,5 +137,5 @@ dependencies {
     implementation 'com.squareup.retrofit2:adapter-rxjava2:2.5.0'
     implementation 'com.uber.autodispose:autodispose-android-archcomponents:1.1.0'
     implementation 'com.uber.autodispose:autodispose-ktx:1.1.0'
-    implementation 'androidx.paging:paging-runtime-ktx:2.1.0-rc01'
+    implementation 'androidx.paging:paging-runtime-ktx:2.1.0'
 }

app/src/main/java/com/keylesspalace/tusky/components/conversation/ConversationsViewModel.kt

@@ -11,8 +11,10 @@ import com.keylesspalace.tusky.db.AppDatabase
 import com.keylesspalace.tusky.network.TimelineCases
 import com.keylesspalace.tusky.util.Listing
 import com.keylesspalace.tusky.util.NetworkState
+import io.reactivex.Single
 import io.reactivex.disposables.CompositeDisposable
 import io.reactivex.rxkotlin.addTo
+import io.reactivex.schedulers.Schedulers
 import javax.inject.Inject
 
 class ConversationsViewModel @Inject constructor(
@@ -20,7 +22,7 @@ class ConversationsViewModel  @Inject constructor(
         private val timelineCases: TimelineCases,
         private val database: AppDatabase,
         private val accountManager: AccountManager
-): ViewModel() {
+) : ViewModel() {
 
     private val repoResult = MutableLiveData<Listing<ConversationEntity>>()
 
@@ -32,7 +34,7 @@ class ConversationsViewModel  @Inject constructor(
 
     fun load() {
         val accountId = accountManager.activeAccount?.id ?: return
-        if(repoResult.value == null) {
+        if (repoResult.value == null) {
             repository.refresh(accountId, false)
         }
         repoResult.value = repository.conversations(accountId)
@@ -49,12 +51,17 @@ class ConversationsViewModel  @Inject constructor(
     fun favourite(favourite: Boolean, position: Int) {
         conversations.value?.getOrNull(position)?.let { conversation ->
             timelineCases.favourite(conversation.lastStatus.toStatus(), favourite)
-                    .subscribe({
+                    .flatMap {
                         val newConversation = conversation.copy(
                                 lastStatus = conversation.lastStatus.copy(favourited = favourite)
                         )
+                        Single.fromCallable {
                             database.conversationDao().insert(newConversation)
-                    }, { t -> Log.w("ConversationViewModel", "Failed to favourite conversation", t) })
+                        }
+                    }
+                    .subscribeOn(Schedulers.io())
+                    .doOnError { t -> Log.w("ConversationViewModel", "Failed to favourite conversation", t) }
+                    .subscribe()
                     .addTo(disposables)
         }
 
@@ -62,11 +69,10 @@ class ConversationsViewModel  @Inject constructor(
 
     fun expandHiddenStatus(expanded: Boolean, position: Int) {
         conversations.value?.getOrNull(position)?.let { conversation ->
-
             val newConversation = conversation.copy(
                     lastStatus = conversation.lastStatus.copy(expanded = expanded)
             )
-            database.conversationDao().insert(newConversation)
+            saveConversationToDb(newConversation)
         }
     }
 
@@ -75,7 +81,7 @@ class ConversationsViewModel  @Inject constructor(
             val newConversation = conversation.copy(
                     lastStatus = conversation.lastStatus.copy(collapsed = collapsed)
             )
-            database.conversationDao().insert(newConversation)
+            saveConversationToDb(newConversation)
         }
     }
 
@@ -84,7 +90,7 @@ class ConversationsViewModel  @Inject constructor(
             val newConversation = conversation.copy(
                     lastStatus = conversation.lastStatus.copy(showingHiddenContent = showing)
             )
-            database.conversationDao().insert(newConversation)
+            saveConversationToDb(newConversation)
         }
     }
 
@@ -93,8 +99,20 @@ class ConversationsViewModel  @Inject constructor(
             /* this is not ideal since deleting last toot from an conversation
                should not delete the conversation but show another toot of the conversation */
             timelineCases.delete(conversation.lastStatus.id)
+            Single.fromCallable {
                         database.conversationDao().delete(conversation)
                     }
+                    .subscribeOn(Schedulers.io())
+                    .subscribe()
+        }
+    }
+
+    private fun saveConversationToDb(conversation: ConversationEntity) {
+        Single.fromCallable {
+                    database.conversationDao().insert(conversation)
+                }
+                .subscribeOn(Schedulers.io())
+                .subscribe()
     }
 
     override fun onCleared() {