Prevented overzealous preloading (#2882)

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerViewer.kt

@@ -168,7 +168,7 @@ abstract class PagerViewer(val activity: ReaderActivity) : BaseViewer {
 
         // Preload next chapter once we're within the last 3 pages of the current chapter
         val inPreloadRange = pages.size - page.number < 3
-        if (inPreloadRange && allowPreload) {
+        if (inPreloadRange && allowPreload && page.chapter == adapter.currentChapter) {
             Timber.d("Request preload next chapter because we're at page ${page.number} of ${pages.size}")
             adapter.nextTransition?.to?.let {
                 activity.requestPreloadChapter(it)

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerViewerAdapter.kt

@@ -24,6 +24,7 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
     var nextTransition: ChapterTransition.Next? = null
         private set
 
+    var currentChapter: ReaderChapter? = null
     /**
      * Updates this adapter with the given [chapters]. It handles setting a few pages of the
      * next/previous chapter to allow seamless transitions and inverting the pages if the viewer
@@ -53,6 +54,8 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
             newItems.addAll(currPages)
         }
 
+        currentChapter = chapters.currChapter
+
         // Add next chapter transition and pages.
         nextTransition = ChapterTransition.Next(chapters.currChapter, chapters.nextChapter)
                 .also {

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonAdapter.kt

@@ -21,6 +21,7 @@ class WebtoonAdapter(val viewer: WebtoonViewer) : RecyclerView.Adapter<RecyclerV
     var items: List<Any> = emptyList()
         private set
 
+    var currentChapter: ReaderChapter? = null
     /**
      * Updates this adapter with the given [chapters]. It handles setting a few pages of the
      * next/previous chapter to allow seamless transitions.
@@ -49,6 +50,8 @@ class WebtoonAdapter(val viewer: WebtoonViewer) : RecyclerView.Adapter<RecyclerV
             newItems.addAll(currPages)
         }
 
+        currentChapter = chapters.currChapter
+
         // Add next chapter transition and pages.
         if (forceTransition || chapters.nextChapter?.state !is ReaderChapter.State.Loaded) {
             newItems.add(ChapterTransition.Next(chapters.currChapter, chapters.nextChapter))

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonViewer.kt

@@ -170,7 +170,7 @@ class WebtoonViewer(val activity: ReaderActivity, val isContinuous: Boolean = tr
 
         // Preload next chapter once we're within the last 3 pages of the current chapter
         val inPreloadRange = pages.size - page.number < 3
-        if (inPreloadRange && allowPreload) {
+        if (inPreloadRange && allowPreload && page.chapter == adapter.currentChapter) {
             Timber.d("Request preload next chapter because we're at page ${page.number} of ${pages.size}")
             val nextItem = adapter.items.getOrNull(adapter.items.size - 1)
             val transitionChapter = (nextItem as? ChapterTransition.Next)?.to ?: (nextItem as?ReaderPage)?.chapter