Make DownloadQueueViewModel collect downloads only while subscribed (#3727)

Assisted-by: Claude:claude-opus-5

app/src/main/java/eu/kanade/tachiyomi/ui/download/DownloadQueueScreen.kt

@@ -19,7 +19,6 @@ import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.material3.animateFloatingActionButton
 import androidx.compose.material3.rememberTopAppBarState
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -41,6 +40,7 @@ import androidx.compose.ui.unit.sp
 import androidx.compose.ui.viewinterop.AndroidView
 import androidx.core.view.ViewCompat
 import androidx.core.view.updatePadding
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.recyclerview.widget.LinearLayoutManager
 import cafe.adriel.voyager.navigator.LocalNavigator
@@ -66,7 +66,7 @@ object DownloadQueueScreen : Screen() {
         val navigator = LocalNavigator.currentOrThrow
         val scope = rememberCoroutineScope()
         val viewModel = viewModel<DownloadQueueViewModel>()
-        val downloadList by viewModel.state.collectAsState()
+        val downloadList by viewModel.state.collectAsStateWithLifecycle()
         val downloadCount by remember {
             derivedStateOf { downloadList.sumOf { it.subItems.size } }
         }
@@ -198,7 +198,7 @@ object DownloadQueueScreen : Screen() {
                 )
             },
             floatingActionButton = {
-                val isRunning by viewModel.isDownloaderRunning.collectAsState()
+                val isRunning by viewModel.isDownloaderRunning.collectAsStateWithLifecycle()
                 SmallExtendedFloatingActionButton(
                     text = {
                         val id = if (isRunning) {

app/src/main/java/eu/kanade/tachiyomi/ui/download/DownloadQueueViewModel.kt

@@ -10,27 +10,36 @@ import eu.kanade.tachiyomi.databinding.DownloadListBinding
 import eu.kanade.tachiyomi.source.model.Page
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
-import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
-import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.WhileSubscribed
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.debounce
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
-import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
 import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Duration.Companion.seconds
 
 class DownloadQueueViewModel(
     private val downloadManager: DownloadManager = Injekt.get(),
 ) : ViewModel() {
 
-    private val _state = MutableStateFlow(emptyList<DownloadHeaderItem>())
-    val state = _state.asStateFlow()
+    val state: StateFlow<List<DownloadHeaderItem>> = downloadManager.queueState
+        .map { downloads ->
+            downloads
+                .groupBy { it.source }
+                .map { entry ->
+                    DownloadHeaderItem(entry.key.id, entry.key.name, entry.value.size).apply {
+                        addSubItems(0, entry.value.map { DownloadItem(it, this) })
+                    }
+                }
+        }
+        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5.seconds), emptyList())
 
     lateinit var controllerBinding: DownloadListBinding
 
@@ -116,22 +125,6 @@ class DownloadQueueViewModel(
         }
     }
 
-    init {
-        viewModelScope.launch {
-            downloadManager.queueState
-                .map { downloads ->
-                    downloads
-                        .groupBy { it.source }
-                        .map { entry ->
-                            DownloadHeaderItem(entry.key.id, entry.key.name, entry.value.size).apply {
-                                addSubItems(0, entry.value.map { DownloadItem(it, this) })
-                            }
-                        }
-                }
-                .collect { newList -> _state.update { newList } }
-        }
-    }
-
     override fun onCleared() {
         for (job in progressJobs.values) {
             job.cancel()
@@ -141,7 +134,7 @@ class DownloadQueueViewModel(
     }
 
     val isDownloaderRunning = downloadManager.isDownloaderRunning
-        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5000), false)
+        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5.seconds), false)
 
     fun getDownloadStatusFlow() = downloadManager.statusFlow()
     fun getDownloadProgressFlow() = downloadManager.progressFlow()