jump to last chapter now moves to where to you last tapped

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryCategoryView.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import android.util.AttributeSet
+import android.view.MotionEvent
 import android.view.View
 import android.widget.FrameLayout
 import eu.davidea.flexibleadapter.FlexibleAdapter
@@ -59,6 +60,8 @@ class LibraryCategoryView @JvmOverloads constructor(context: Context, attrs: Att
      */
     private var subscriptions = CompositeSubscription()
 
+    private var lastTouchUpY = 0f
+
     fun onCreate(controller: LibraryController) {
         this.controller = controller
 
@@ -210,11 +213,18 @@ class LibraryCategoryView @JvmOverloads constructor(context: Context, attrs: Att
             toggleSelection(position)
             return true
         } else {
-            openManga(item.manga)
+            openManga(item.manga, lastTouchUpY)
             return false
         }
     }
 
+    override fun dispatchTouchEvent(ev: MotionEvent?): Boolean {
+        when (ev?.action) {
+            MotionEvent.ACTION_UP -> lastTouchUpY = ev?.y
+        }
+        return super.dispatchTouchEvent(ev)
+    }
+
     /**
      * Called when a manga is long clicked.
      *
@@ -230,8 +240,8 @@ class LibraryCategoryView @JvmOverloads constructor(context: Context, attrs: Att
      *
      * @param manga the manga to open.
      */
-    private fun openManga(manga: Manga) {
-        controller.openManga(manga)
+    private fun openManga(manga: Manga, startY:Float?) {
+        controller.openManga(manga, startY)
     }
 
     /**

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryController.kt

@@ -428,11 +428,11 @@ class LibraryController(
         actionMode = null
     }
 
-    fun openManga(manga: Manga) {
+    fun openManga(manga: Manga, startY: Float?) {
         // Notify the presenter a manga is being opened.
         presenter.onOpenManga()
 
-        router.pushController(MangaController(manga).withFadeTransaction())
+        router.pushController(MangaController(manga, startY).withFadeTransaction())
     }
 
     /**

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaController.kt

@@ -48,6 +48,17 @@ class MangaController : RxController, TabbedController {
         }
     }
 
+    constructor(manga: Manga?, startY:Float?) : super(Bundle().apply {
+        putLong(MANGA_EXTRA, manga?.id ?: 0)
+        putBoolean(FROM_CATALOGUE_EXTRA, false)
+    }) {
+        this.manga = manga
+        startingChapterYPos = startY
+        if (manga != null) {
+            source = Injekt.get<SourceManager>().getOrStub(manga.source)
+        }
+    }
+
     constructor(mangaId: Long) : this(
             Injekt.get<DatabaseHelper>().getManga(mangaId).executeAsBlocking())
 
@@ -60,6 +71,8 @@ class MangaController : RxController, TabbedController {
     var source: Source? = null
         private set
 
+    var startingChapterYPos:Float? = null
+
     private var adapter: MangaDetailAdapter? = null
 
     val fromCatalogue = args.getBoolean(FROM_CATALOGUE_EXTRA, false)
@@ -164,7 +177,7 @@ class MangaController : RxController, TabbedController {
             if (!router.hasRootController()) {
                 val controller = when (position) {
                     INFO_CONTROLLER -> MangaInfoController()
-                    CHAPTERS_CONTROLLER -> ChaptersController()
+                    CHAPTERS_CONTROLLER -> ChaptersController(startingChapterYPos)
                     TRACK_CONTROLLER -> TrackController()
                     else -> error("Wrong position $position")
                 }

app/src/main/java/eu/kanade/tachiyomi/ui/manga/chapter/ChaptersController.kt

@@ -36,7 +36,7 @@ import androidx.core.view.ViewCompat
 import androidx.recyclerview.widget.RecyclerView
 import kotlin.math.*
 
-class ChaptersController : NucleusController<ChaptersPresenter>(),
+class ChaptersController() : NucleusController<ChaptersPresenter>(),
         ActionMode.Callback,
         FlexibleAdapter.OnItemClickListener,
         FlexibleAdapter.OnItemLongClickListener,
@@ -47,6 +47,10 @@ class ChaptersController : NucleusController<ChaptersPresenter>(),
         DownloadCustomChaptersDialog.Listener,
         DeleteChaptersDialog.Listener {
 
+    constructor(startY: Float?) : this() {
+        this.startingChapterYPos = startY
+    }
+
     /**
      * Adapter containing a list of chapters.
      */
@@ -69,6 +73,7 @@ class ChaptersController : NucleusController<ChaptersPresenter>(),
         setHasOptionsMenu(true)
         setOptionsMenuHidden(true)
     }
+    var startingChapterYPos:Float? = null
 
     override fun createPresenter(): ChaptersPresenter {
         val ctrl = parentController as MangaController
@@ -233,11 +238,15 @@ class ChaptersController : NucleusController<ChaptersPresenter>(),
     }
 
     private fun scrollToUnread() {
+        if (adapter?.items.isNullOrEmpty()) return
         if (scrollToUnread) {
             val index = presenter.getFirstUnreadIndex()
-            val centerOfScreen = recycler.height / 2 - 96
-            (recycler.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(index,
-                centerOfScreen)
+            val centerOfScreen =
+                if (startingChapterYPos != null) startingChapterYPos!!.toInt() - recycler.top - 96
+                else recycler.height / 2 - 96
+            (recycler.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(
+                index, centerOfScreen
+            )
         }
         scrollToUnread = false
     }