diff --git a/app/src/main/java/me/ash/reader/ui/page/home/feeds/FeedsViewModel.kt b/app/src/main/java/me/ash/reader/ui/page/home/feeds/FeedsViewModel.kt
index 43c9f63..6030473 100644
--- a/app/src/main/java/me/ash/reader/ui/page/home/feeds/FeedsViewModel.kt
+++ b/app/src/main/java/me/ash/reader/ui/page/home/feeds/FeedsViewModel.kt
@@ -5,12 +5,14 @@ import androidx.compose.foundation.lazy.LazyListState
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
-import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.launch
 import me.ash.reader.R
 import me.ash.reader.data.entity.Account
 import me.ash.reader.data.entity.GroupWithFeed
+import me.ash.reader.data.module.DispatcherDefault
+import me.ash.reader.data.module.DispatcherIO
 import me.ash.reader.data.repository.AccountRepository
 import me.ash.reader.data.repository.OpmlRepository
 import me.ash.reader.data.repository.RssRepository
@@ -24,6 +26,10 @@ class FeedsViewModel @Inject constructor(
     private val rssRepository: RssRepository,
     private val opmlRepository: OpmlRepository,
     private val stringsRepository: StringsRepository,
+    @DispatcherDefault
+    private val dispatcherDefault: CoroutineDispatcher,
+    @DispatcherIO
+    private val dispatcherIO: CoroutineDispatcher,
 ) : ViewModel() {
     private val _viewState = MutableStateFlow(FeedsViewState())
     val viewState: StateFlow<FeedsViewState> = _viewState.asStateFlow()
@@ -38,7 +44,7 @@ class FeedsViewModel @Inject constructor(
     }
 
     private fun fetchAccount() {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             _viewState.update {
                 it.copy(
                     account = accountRepository.getCurrentAccount()
@@ -48,7 +54,7 @@ class FeedsViewModel @Inject constructor(
     }
 
     private fun exportAsOpml(callback: (String) -> Unit = {}) {
-        viewModelScope.launch(Dispatchers.Default) {
+        viewModelScope.launch(dispatcherDefault) {
             try {
                 callback(opmlRepository.saveToString())
             } catch (e: Exception) {
@@ -58,7 +64,7 @@ class FeedsViewModel @Inject constructor(
     }
 
     private fun fetchData(filterState: FilterState) {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             pullFeeds(
                 isStarred = filterState.filter.isStarred(),
                 isUnread = filterState.filter.isUnread(),
@@ -118,7 +124,7 @@ class FeedsViewModel @Inject constructor(
             }
         }.catch {
             Log.e("RLog", "catch in articleRepository.pullFeeds(): ${it.message}")
-        }.flowOn(Dispatchers.Default).collect()
+        }.flowOn(dispatcherDefault).collect()
     }
 
     private fun scrollToItem(index: Int) {
diff --git a/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/feed/FeedOptionViewModel.kt b/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/feed/FeedOptionViewModel.kt
index d31c510..bbe0aef 100644
--- a/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/feed/FeedOptionViewModel.kt
+++ b/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/feed/FeedOptionViewModel.kt
@@ -7,8 +7,8 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.google.accompanist.pager.ExperimentalPagerApi
 import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -17,6 +17,8 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import me.ash.reader.data.entity.Feed
 import me.ash.reader.data.entity.Group
+import me.ash.reader.data.module.DispatcherIO
+import me.ash.reader.data.module.DispatcherMain
 import me.ash.reader.data.repository.RssRepository
 import javax.inject.Inject
 
@@ -27,12 +29,16 @@ import javax.inject.Inject
 @HiltViewModel
 class FeedOptionViewModel @Inject constructor(
     private val rssRepository: RssRepository,
+    @DispatcherMain
+    private val dispatcherMain: CoroutineDispatcher,
+    @DispatcherIO
+    private val dispatcherIO: CoroutineDispatcher,
 ) : ViewModel() {
     private val _viewState = MutableStateFlow(FeedOptionViewState())
     val viewState: StateFlow<FeedOptionViewState> = _viewState.asStateFlow()
 
     init {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             rssRepository.get().pullGroups().collect { groups ->
                 _viewState.update {
                     it.copy(
@@ -121,7 +127,7 @@ class FeedOptionViewModel @Inject constructor(
     }
 
     private fun selectedGroup(groupId: String) {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             _viewState.value.feed?.let {
                 rssRepository.get().updateFeed(
                     it.copy(
@@ -134,7 +140,7 @@ class FeedOptionViewModel @Inject constructor(
     }
 
     private fun changeParseFullContentPreset() {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             _viewState.value.feed?.let {
                 rssRepository.get().updateFeed(
                     it.copy(
@@ -147,7 +153,7 @@ class FeedOptionViewModel @Inject constructor(
     }
 
     private fun changeAllowNotificationPreset() {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             _viewState.value.feed?.let {
                 rssRepository.get().updateFeed(
                     it.copy(
@@ -161,9 +167,9 @@ class FeedOptionViewModel @Inject constructor(
 
     private fun delete(callback: () -> Unit = {}) {
         _viewState.value.feed?.let {
-            viewModelScope.launch(Dispatchers.IO) {
+            viewModelScope.launch(dispatcherIO) {
                 rssRepository.get().deleteFeed(it)
-                withContext(Dispatchers.Main) {
+                withContext(dispatcherMain) {
                     callback()
                 }
             }
@@ -204,9 +210,9 @@ class FeedOptionViewModel @Inject constructor(
 
     private fun clear(callback: () -> Unit = {}) {
         _viewState.value.feed?.let {
-            viewModelScope.launch(Dispatchers.IO) {
+            viewModelScope.launch(dispatcherIO) {
                 rssRepository.get().deleteArticles(feed = it)
-                withContext(Dispatchers.Main) {
+                withContext(dispatcherMain) {
                     callback()
                 }
             }
diff --git a/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/group/GroupOptionViewModel.kt b/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/group/GroupOptionViewModel.kt
index b696c8d..59415b4 100644
--- a/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/group/GroupOptionViewModel.kt
+++ b/app/src/main/java/me/ash/reader/ui/page/home/feeds/option/group/GroupOptionViewModel.kt
@@ -7,8 +7,8 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.google.accompanist.pager.ExperimentalPagerApi
 import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -16,6 +16,8 @@ import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import me.ash.reader.data.entity.Group
+import me.ash.reader.data.module.DispatcherIO
+import me.ash.reader.data.module.DispatcherMain
 import me.ash.reader.data.repository.RssRepository
 import javax.inject.Inject
 
@@ -26,12 +28,16 @@ import javax.inject.Inject
 @HiltViewModel
 class GroupOptionViewModel @Inject constructor(
     private val rssRepository: RssRepository,
+    @DispatcherMain
+    private val dispatcherMain: CoroutineDispatcher,
+    @DispatcherIO
+    private val dispatcherIO: CoroutineDispatcher,
 ) : ViewModel() {
     private val _viewState = MutableStateFlow(GroupOptionViewState())
     val viewState: StateFlow<GroupOptionViewState> = _viewState.asStateFlow()
 
     init {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             rssRepository.get().pullGroups().collect { groups ->
                 _viewState.update {
                     it.copy(
@@ -106,9 +112,9 @@ class GroupOptionViewModel @Inject constructor(
 
     private fun allAllowNotification(isNotification: Boolean, callback: () -> Unit = {}) {
         _viewState.value.group?.let {
-            viewModelScope.launch(Dispatchers.IO) {
+            viewModelScope.launch(dispatcherIO) {
                 rssRepository.get().groupAllowNotification(it, isNotification)
-                withContext(Dispatchers.Main) {
+                withContext(dispatcherMain) {
                     callback()
                 }
             }
@@ -125,9 +131,9 @@ class GroupOptionViewModel @Inject constructor(
 
     private fun allParseFullContent(isFullContent: Boolean, callback: () -> Unit = {}) {
         _viewState.value.group?.let {
-            viewModelScope.launch(Dispatchers.IO) {
+            viewModelScope.launch(dispatcherIO) {
                 rssRepository.get().groupParseFullContent(it, isFullContent)
-                withContext(Dispatchers.Main) {
+                withContext(dispatcherMain) {
                     callback()
                 }
             }
@@ -144,9 +150,9 @@ class GroupOptionViewModel @Inject constructor(
 
     private fun delete(callback: () -> Unit = {}) {
         _viewState.value.group?.let {
-            viewModelScope.launch(Dispatchers.IO) {
+            viewModelScope.launch(dispatcherIO) {
                 rssRepository.get().deleteGroup(it)
-                withContext(Dispatchers.Main) {
+                withContext(dispatcherMain) {
                     callback()
                 }
             }
@@ -179,9 +185,9 @@ class GroupOptionViewModel @Inject constructor(
 
     private fun clear(callback: () -> Unit = {}) {
         _viewState.value.group?.let {
-            viewModelScope.launch(Dispatchers.IO) {
+            viewModelScope.launch(dispatcherIO) {
                 rssRepository.get().deleteArticles(group = it)
-                withContext(Dispatchers.Main) {
+                withContext(dispatcherMain) {
                     callback()
                 }
             }
@@ -191,9 +197,9 @@ class GroupOptionViewModel @Inject constructor(
     private fun allMoveToGroup(callback: () -> Unit) {
         _viewState.value.group?.let { group ->
             _viewState.value.targetGroup?.let { targetGroup ->
-                viewModelScope.launch(Dispatchers.IO) {
+                viewModelScope.launch(dispatcherIO) {
                     rssRepository.get().groupMoveToTargetGroup(group, targetGroup)
-                    withContext(Dispatchers.Main) {
+                    withContext(dispatcherMain) {
                         callback()
                     }
                 }
diff --git a/app/src/main/java/me/ash/reader/ui/page/home/feeds/subscribe/SubscribeViewModel.kt b/app/src/main/java/me/ash/reader/ui/page/home/feeds/subscribe/SubscribeViewModel.kt
index 2b4f807..9bdc1f1 100644
--- a/app/src/main/java/me/ash/reader/ui/page/home/feeds/subscribe/SubscribeViewModel.kt
+++ b/app/src/main/java/me/ash/reader/ui/page/home/feeds/subscribe/SubscribeViewModel.kt
@@ -5,7 +5,7 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.google.accompanist.pager.ExperimentalPagerApi
 import dagger.hilt.android.lifecycle.HiltViewModel
-import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.async
 import kotlinx.coroutines.flow.*
@@ -14,6 +14,7 @@ import me.ash.reader.R
 import me.ash.reader.data.entity.Article
 import me.ash.reader.data.entity.Feed
 import me.ash.reader.data.entity.Group
+import me.ash.reader.data.module.DispatcherIO
 import me.ash.reader.data.repository.OpmlRepository
 import me.ash.reader.data.repository.RssHelper
 import me.ash.reader.data.repository.RssRepository
@@ -29,6 +30,8 @@ class SubscribeViewModel @Inject constructor(
     private val rssRepository: RssRepository,
     private val rssHelper: RssHelper,
     private val stringsRepository: StringsRepository,
+    @DispatcherIO
+    private val dispatcherIO: CoroutineDispatcher,
 ) : ViewModel() {
     private val _viewState = MutableStateFlow(SubscribeViewState())
     val viewState: StateFlow<SubscribeViewState> = _viewState.asStateFlow()
@@ -77,7 +80,7 @@ class SubscribeViewModel @Inject constructor(
     }
 
     private fun importFromInputStream(inputStream: InputStream) {
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             try {
                 opmlRepository.saveToDatabase(inputStream)
                 rssRepository.get().doSync()
@@ -90,7 +93,7 @@ class SubscribeViewModel @Inject constructor(
     private fun subscribe() {
         val feed = _viewState.value.feed ?: return
         val articles = _viewState.value.articles
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             val groupId = async {
                 _viewState.value.selectedGroupId
             }
@@ -145,7 +148,7 @@ class SubscribeViewModel @Inject constructor(
 
     private fun search() {
         searchJob?.cancel()
-        viewModelScope.launch(Dispatchers.IO) {
+        viewModelScope.launch(dispatcherIO) {
             try {
                 _viewState.update {
                     it.copy(