Change withContext to flowOn.

Change-Id: I679f11aa0bcae1d2de54b0373a284f83d0f0c81b

core/data/src/main/kotlin/com/google/samples/apps/nowinandroid/core/data/repository/DefaultSearchContentsRepository.kt

@@ -33,6 +33,7 @@ import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.withContext
 import javax.inject.Inject
@@ -77,13 +78,11 @@ internal class DefaultSearchContentsRepository @Inject constructor(
             .distinctUntilChanged()
             .flatMapLatest(topicDao::getTopicEntities)
         return combine(newsResourcesFlow, topicsFlow) { newsResources, topics ->
-            withContext(defaultDispatcher) {
-                SearchResult(
-                    topics = topics.map { it.asExternalModel() },
-                    newsResources = newsResources.map { it.asExternalModel() },
-                )
-            }
-        }
+            SearchResult(
+                topics = topics.map { it.asExternalModel() },
+                newsResources = newsResources.map { it.asExternalModel() },
+            )
+        }.flowOn(defaultDispatcher)
     }
 
     override fun getSearchContentsCount(): Flow<Int> =
@@ -91,8 +90,6 @@ internal class DefaultSearchContentsRepository @Inject constructor(
             newsResourceFtsDao.getCount(),
             topicFtsDao.getCount(),
         ) { newsResourceCount, topicsCount ->
-            withContext(defaultDispatcher) {
-                newsResourceCount + topicsCount
-            }
-        }
+            newsResourceCount + topicsCount
+        }.flowOn(defaultDispatcher)
 }

core/domain/src/main/kotlin/com/google/samples/apps/nowinandroid/core/domain/GetFollowableTopicsUseCase.kt

@@ -26,7 +26,7 @@ import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.Default
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.withContext
+import kotlinx.coroutines.flow.flowOn
 import javax.inject.Inject
 
 /**
@@ -46,20 +46,18 @@ class GetFollowableTopicsUseCase @Inject constructor(
         userDataRepository.userData,
         topicsRepository.getTopics(),
     ) { userData, topics ->
-        withContext(defaultDispatcher) {
-            val followedTopics = topics
-                .map { topic ->
-                    FollowableTopic(
-                        topic = topic,
-                        isFollowed = topic.id in userData.followedTopics,
-                    )
-                }
-            when (sortBy) {
-                NAME -> followedTopics.sortedBy { it.topic.name }
-                else -> followedTopics
+        val followedTopics = topics
+            .map { topic ->
+                FollowableTopic(
+                    topic = topic,
+                    isFollowed = topic.id in userData.followedTopics,
+                )
             }
+        when (sortBy) {
+            NAME -> followedTopics.sortedBy { it.topic.name }
+            else -> followedTopics
         }
-    }
+    }.flowOn(defaultDispatcher)
 }
 
 enum class TopicSortField {

core/domain/src/main/kotlin/com/google/samples/apps/nowinandroid/core/domain/GetSearchContentsUseCase.kt

@@ -28,7 +28,7 @@ import com.google.samples.apps.nowinandroid.core.network.NiaDispatchers.Default
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.withContext
+import kotlinx.coroutines.flow.flowOn
 import javax.inject.Inject
 
 /**
@@ -52,20 +52,18 @@ private fun Flow<SearchResult>.mapToUserSearchResult(
     defaultDispatcher: CoroutineDispatcher,
 ): Flow<UserSearchResult> =
     combine(userDataStream) { searchResult, userData ->
-        withContext(defaultDispatcher) {
-            UserSearchResult(
-                topics = searchResult.topics.map { topic ->
-                    FollowableTopic(
-                        topic = topic,
-                        isFollowed = topic.id in userData.followedTopics,
-                    )
-                },
-                newsResources = searchResult.newsResources.map { news ->
-                    UserNewsResource(
-                        newsResource = news,
-                        userData = userData,
-                    )
-                },
-            )
-        }
-    }
+        UserSearchResult(
+            topics = searchResult.topics.map { topic ->
+                FollowableTopic(
+                    topic = topic,
+                    isFollowed = topic.id in userData.followedTopics,
+                )
+            },
+            newsResources = searchResult.newsResources.map { news ->
+                UserNewsResource(
+                    newsResource = news,
+                    userData = userData,
+                )
+            },
+        )
+    }.flowOn(defaultDispatcher)