Move the reader viewer out of the ViewModel

app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt

@@ -73,6 +73,7 @@ import eu.kanade.tachiyomi.ui.reader.setting.ReaderPreferences
 import eu.kanade.tachiyomi.ui.reader.setting.ReaderSettingsViewModel
 import eu.kanade.tachiyomi.ui.reader.setting.ReadingMode
 import eu.kanade.tachiyomi.ui.reader.viewer.ReaderProgressIndicator
+import eu.kanade.tachiyomi.ui.reader.viewer.Viewer
 import eu.kanade.tachiyomi.ui.reader.viewer.pager.R2LPagerViewer
 import eu.kanade.tachiyomi.ui.reader.viewer.webgpu.WebGpuViewer
 import eu.kanade.tachiyomi.ui.webview.WebViewActivity
@@ -82,6 +83,7 @@ import eu.kanade.tachiyomi.util.system.toShareIntent
 import eu.kanade.tachiyomi.util.system.toast
 import eu.kanade.tachiyomi.util.view.setComposeContent
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.drop
@@ -137,6 +139,12 @@ class ReaderActivity : BaseActivity() {
 
     private var loadingIndicator: ReaderProgressIndicator? = null
 
+    /**
+     * Viewer used to display the pages (pager, webtoon, ...).
+     */
+    private val viewerFlow = MutableStateFlow<Viewer?>(null)
+    private val viewer: Viewer? inline get() = viewerFlow.value
+
     var isScrollingThroughPages = false
         private set
 
@@ -251,6 +259,7 @@ class ReaderActivity : BaseActivity() {
         val settingsviewModel = remember {
             ReaderSettingsViewModel(
                 readerState = viewModel.state,
+                viewerFlow = viewerFlow,
                 onChangeReadingMode = viewModel::setMangaReadingMode,
                 onChangeOrientation = viewModel::setMangaOrientationType,
                 preferences = readerPreferences,
@@ -337,7 +346,7 @@ class ReaderActivity : BaseActivity() {
      */
     override fun onDestroy() {
         super.onDestroy()
-        viewModel.state.value.viewer?.destroy()
+        viewer?.destroy()
         config = null
         menuToggleToast?.cancel()
         readingModeToast?.cancel()
@@ -408,7 +417,7 @@ class ReaderActivity : BaseActivity() {
      * Dispatches a key event. If the viewer doesn't handle it, call the default implementation.
      */
     override fun dispatchKeyEvent(event: KeyEvent): Boolean {
-        val handled = viewModel.state.value.viewer?.handleKeyEvent(event) ?: false
+        val handled = viewer?.handleKeyEvent(event) ?: false
         return handled || super.dispatchKeyEvent(event)
     }
 
@@ -417,7 +426,7 @@ class ReaderActivity : BaseActivity() {
      * implementation.
      */
     override fun dispatchGenericMotionEvent(event: MotionEvent): Boolean {
-        val handled = viewModel.state.value.viewer?.handleGenericMotionEvent(event) ?: false
+        val handled = viewer?.handleGenericMotionEvent(event) ?: false
         return handled || super.dispatchGenericMotionEvent(event)
     }
 
@@ -446,6 +455,7 @@ class ReaderActivity : BaseActivity() {
     @Composable
     fun AppBars(state: ReaderViewModel.State) {
         val isHttpSource = state.source is HttpSource
+        val viewer by viewerFlow.collectAsState()
 
         val cropBorderPaged by readerPreferences.cropBorders.collectAsState()
         val cropBorderWebtoon by readerPreferences.cropBordersWebtoon.collectAsState()
@@ -473,7 +483,7 @@ class ReaderActivity : BaseActivity() {
             onShare = ::shareChapter.takeIf { isHttpSource },
 
             chapterNavigatorType = if (!verticalNavigator) {
-                if (state.viewer is R2LPagerViewer || (state.viewer as? WebGpuViewer)?.isReversed ?: false) {
+                if (viewer is R2LPagerViewer || (viewer as? WebGpuViewer)?.isReversed ?: false) {
                     ChapterNavigatorType.HORIZONTAL_RTL
                 } else {
                     ChapterNavigatorType.HORIZONTAL_LTR
@@ -534,7 +544,7 @@ class ReaderActivity : BaseActivity() {
      * Called from the presenter when a manga is ready. Used to instantiate the appropriate viewer.
      */
     private fun updateViewer() {
-        val prevViewer = viewModel.state.value.viewer
+        val prevViewer = viewer
         val newViewer = ReadingMode.toViewer(viewModel.getMangaReadingMode(), this)
 
         if (window.sharedElementEnterTransition is MaterialContainerTransform) {
@@ -551,7 +561,7 @@ class ReaderActivity : BaseActivity() {
             prevViewer.destroy()
             binding.viewerContainer.removeAllViews()
         }
-        viewModel.onViewerLoaded(newViewer)
+        viewerFlow.value = newViewer
         updateViewerInset(readerPreferences.fullscreen.get(), readerPreferences.drawUnderCutout.get())
         binding.viewerContainer.addView(newViewer.getView())
 
@@ -616,7 +626,7 @@ class ReaderActivity : BaseActivity() {
     @SuppressLint("RestrictedApi")
     private fun setChapters(viewerChapters: ViewerChapters) {
         binding.readerContainer.removeView(loadingIndicator)
-        viewModel.state.value.viewer?.setChapters(viewerChapters)
+        viewer?.setChapters(viewerChapters)
 
         lifecycleScope.launch(Dispatchers.IO) {
             viewModel.getChapterUrl()?.let { url ->
@@ -654,7 +664,7 @@ class ReaderActivity : BaseActivity() {
      * page is not found.
      */
     private fun moveToPageIndex(index: Int) {
-        val viewer = viewModel.state.value.viewer ?: return
+        val viewer = this.viewer ?: return
         val currentChapter = viewModel.state.value.currentChapter ?: return
         val page = currentChapter.pages?.getOrNull(index) ?: return
         viewer.moveToPage(page)

app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderViewModel.kt

@@ -47,7 +47,6 @@ import eu.kanade.tachiyomi.ui.reader.model.ViewerChapters
 import eu.kanade.tachiyomi.ui.reader.setting.ReaderOrientation
 import eu.kanade.tachiyomi.ui.reader.setting.ReaderPreferences
 import eu.kanade.tachiyomi.ui.reader.setting.ReadingMode
-import eu.kanade.tachiyomi.ui.reader.viewer.Viewer
 import eu.kanade.tachiyomi.util.chapter.filterDownloaded
 import eu.kanade.tachiyomi.util.chapter.removeDuplicates
 import eu.kanade.tachiyomi.util.editCover
@@ -527,12 +526,6 @@ class ReaderViewModel(
         eventChannel.trySend(Event.ReloadViewerChapters)
     }
 
-    fun onViewerLoaded(viewer: Viewer?) {
-        mutableState.update {
-            it.copy(viewer = viewer)
-        }
-    }
-
     /**
      * Called every time a page changes on the reader. Used to mark the flag of chapters being
      * read, update tracking services, enqueue downloaded chapter deletion, and updating the active chapter if this
@@ -1110,11 +1103,6 @@ class ReaderViewModel(
         val bookmarked: Boolean = false,
         val isLoadingAdjacentChapter: Boolean = false,
         val currentPage: Int = -1,
-
-        /**
-         * Viewer used to display the pages (pager, webtoon, ...).
-         */
-        val viewer: Viewer? = null,
         val dialog: Dialog? = null,
         val menuVisible: Boolean = false,
         @IntRange(from = -100, to = 100) val brightnessOverlayValue: Int = 0,

app/src/main/java/eu/kanade/tachiyomi/ui/reader/setting/ReaderSettingsViewModel.kt

@@ -3,6 +3,7 @@ package eu.kanade.tachiyomi.ui.reader.setting
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import eu.kanade.tachiyomi.ui.reader.ReaderViewModel
+import eu.kanade.tachiyomi.ui.reader.viewer.Viewer
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.distinctUntilChanged
@@ -11,16 +12,12 @@ import kotlinx.coroutines.flow.stateIn
 
 class ReaderSettingsViewModel(
     readerState: StateFlow<ReaderViewModel.State>,
+    val viewerFlow: StateFlow<Viewer?>,
     val onChangeReadingMode: (ReadingMode) -> Unit,
     val onChangeOrientation: (ReaderOrientation) -> Unit,
     val preferences: ReaderPreferences,
 ) : ViewModel() {
 
-    val viewerFlow = readerState
-        .map { it.viewer }
-        .distinctUntilChanged()
-        .stateIn(viewModelScope, SharingStarted.Lazily, null)
-
     val mangaFlow = readerState
         .map { it.manga }
         .distinctUntilChanged()