Minor reader cleanup

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

@@ -1,6 +1,6 @@
 package eu.kanade.tachiyomi.ui.reader.model
 
-sealed class ChapterTransition {
+sealed class ChapterTransition : ReaderItem {
 
     abstract val from: ReaderChapter
     abstract val to: ReaderChapter?

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

@@ -0,0 +1,3 @@
+package eu.kanade.tachiyomi.ui.reader.model
+
+sealed interface ReaderItem

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

@@ -15,7 +15,7 @@ open class ReaderPage(
     // SY <--
     var stream: (() -> InputStream)? = null,
 
-) : Page(index, url, imageUrl, null) {
+) : Page(index, url, imageUrl, null), ReaderItem {
 
     open lateinit var chapter: ReaderChapter
 

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

@@ -15,6 +15,7 @@ import eu.kanade.tachiyomi.data.download.DownloadManager
 import eu.kanade.tachiyomi.ui.reader.ReaderActivity
 import eu.kanade.tachiyomi.ui.reader.model.ChapterTransition
 import eu.kanade.tachiyomi.ui.reader.model.InsertPage
+import eu.kanade.tachiyomi.ui.reader.model.ReaderItem
 import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
 import eu.kanade.tachiyomi.ui.reader.model.ViewerChapters
 import eu.kanade.tachiyomi.ui.reader.viewer.BaseViewer
@@ -55,7 +56,7 @@ abstract class PagerViewer(val activity: ReaderActivity) : BaseViewer {
      * Currently active item. It can be a chapter page or a chapter transition.
      */
     /* [EXH] private */
-    var currentPage: Any? = null
+    var currentPage: ReaderItem? = null
 
     /**
      * Viewer chapters to set when the pager enters idle mode. Otherwise, if the view was settling
@@ -83,7 +84,7 @@ abstract class PagerViewer(val activity: ReaderActivity) : BaseViewer {
             }
         }
 
-    private var pagerListener = object : ViewPager.SimpleOnPageChangeListener() {
+    private val pagerListener = object : ViewPager.SimpleOnPageChangeListener() {
         override fun onPageSelected(position: Int) {
             if (activity.isScrollingThroughPages.not()) {
                 activity.hideMenu()

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

@@ -5,6 +5,7 @@ import android.view.ViewGroup
 import eu.kanade.tachiyomi.ui.reader.model.ChapterTransition
 import eu.kanade.tachiyomi.ui.reader.model.InsertPage
 import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
+import eu.kanade.tachiyomi.ui.reader.model.ReaderItem
 import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
 import eu.kanade.tachiyomi.ui.reader.model.ViewerChapters
 import eu.kanade.tachiyomi.ui.reader.viewer.hasMissingChapters
@@ -23,13 +24,13 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
     /**
      * Paired list of currently set items.
      */
-    var joinedItems: MutableList<Pair<Any, Any?>> = mutableListOf()
+    var joinedItems: MutableList<Pair<ReaderItem, ReaderItem?>> = mutableListOf()
         private set
 
     /**
      * Single list of items
      */
-    private var subItems: MutableList<Any> = mutableListOf()
+    private var subItems: MutableList<ReaderItem> = mutableListOf()
 
     /**
      * Holds preprocessed items so they don't get removed when changing chapter
@@ -62,7 +63,7 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
      * has R2L direction.
      */
     fun setChapters(chapters: ViewerChapters, forceTransition: Boolean) {
-        val newItems = mutableListOf<Any>()
+        val newItems = mutableListOf<ReaderItem>()
 
         // Forces chapter transition if there is missing chapters
         val prevHasMissingChapters = hasMissingChapters(chapters.currChapter, chapters.prevChapter)
@@ -233,30 +234,33 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
             subItems.forEach {
                 (it as? ReaderPage)?.shiftedPage = false
             }
-            this.joinedItems = subItems.map { Pair<Any, Any?>(it, null) }.toMutableList()
+            this.joinedItems = subItems.map { Pair<ReaderItem, ReaderItem?>(it, null) }.toMutableList()
             if (viewer is R2LPagerViewer) {
                 joinedItems.reverse()
             }
         } else {
             val pagedItems = mutableListOf<MutableList<ReaderPage?>>()
-            val otherItems = mutableListOf<Any>()
+            val otherItems = mutableListOf<ReaderItem>()
             pagedItems.add(mutableListOf())
             // Step 1: segment the pages and transition pages
             subItems.forEach {
-                if (it is ReaderPage) {
+                when (it) {
-                    if (pagedItems.last().lastOrNull() != null &&
+                    is ReaderPage -> {
-                        pagedItems.last().last()?.chapter?.chapter?.id != it.chapter.chapter.id
+                        if (pagedItems.last().lastOrNull() != null &&
-                    ) {
+                            pagedItems.last().last()?.chapter?.chapter?.id != it.chapter.chapter.id
+                        ) {
+                            pagedItems.add(mutableListOf())
+                        }
+                        pagedItems.last().add(it)
+                    }
+                    is ChapterTransition -> {
+                        otherItems.add(it)
                         pagedItems.add(mutableListOf())
                     }
-                    pagedItems.last().add(it)
-                } else {
-                    otherItems.add(it)
-                    pagedItems.add(mutableListOf())
                 }
             }
             var pagedIndex = 0
-            val subJoinedItems = mutableListOf<Pair<Any, Any?>>()
+            val subJoinedItems = mutableListOf<Pair<ReaderItem, ReaderItem?>>()
             // Step 2: run through each set of pages
             pagedItems.forEach { items ->