Reader fixes

app/src/main/java/org/koitharu/kotatsu/ui/reader/BaseReaderFragment.kt

@@ -18,7 +18,7 @@ abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragmen
 
 	abstract val hasItems: Boolean
 
-	abstract val currentPageIndex: Int
+	protected abstract val currentPageIndex: Int
 
 	abstract val pages: List<MangaPage>
 
@@ -46,6 +46,11 @@ abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragmen
 
 	override fun onChaptersLoader(chapters: List<MangaChapter>) = Unit
 
+	override fun onDestroyView() {
+		chaptersMap.clear()
+		super.onDestroyView()
+	}
+
 	final override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>) {
 		when {
 			chaptersMap.isEmpty() -> {
@@ -68,6 +73,33 @@ abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragmen
 		}
 	}
 
+	fun switchPageBy(delta: Int) {
+		setCurrentPage(currentPageIndex + delta, true)
+	}
+
+	fun findCurrentPageIndex(chapterId: Long): Int {
+		val pages = this.pages
+		var offset = 0
+		for ((id, count) in chaptersMap) {
+			if (id == chapterId) {
+				return currentPageIndex - offset
+			}
+			offset += count
+		}
+		return -1
+	}
+
+	fun getPages(chapterId: Long): List<MangaPage>? {
+		var offset = 0
+		for ((id, count) in chaptersMap) {
+			if (id == chapterId) {
+				return pages.subList(offset, offset + count - 1)
+			}
+			offset += count
+		}
+		return null
+	}
+
 	private fun shouldAppend(chapterId: Long): Boolean {
 		val chapters = lastState?.manga?.chapters ?: return false
 		val lastChapterId = chaptersMap.peekLast()?.first ?: return false

app/src/main/java/org/koitharu/kotatsu/ui/reader/ReaderActivity.kt

@@ -89,7 +89,7 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 
 	override fun onPause() {
 		reader?.let {
-			state = state.copy(page = it.currentPageIndex)
+			state = state.copy(page = it.findCurrentPageIndex(state.chapterId))
 			presenter.saveState(state)
 		}
 		super.onPause()
@@ -126,10 +126,15 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 		}
 		R.id.action_pages_thumbs -> {
 			if (reader?.hasItems == true) {
-				PagesThumbnailsSheet.show(
-					supportFragmentManager, reader!!.pages,
-					state.chapter?.name ?: title?.toString().orEmpty()
-				)
+				val pages = reader?.getPages(state.chapterId)
+				if (pages != null) {
+					PagesThumbnailsSheet.show(
+						supportFragmentManager, pages,
+						state.chapter?.name ?: title?.toString().orEmpty()
+					)
+				} else {
+					showWaitWhileLoading()
+				}
 			} else {
 				showWaitWhileLoading()
 			}
@@ -154,7 +159,9 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 	}
 
 	override fun onLoadingStateChanged(isLoading: Boolean) {
-		layout_loading.isVisible = isLoading
+		val hasPages = reader?.hasItems == true
+		layout_loading.isVisible = isLoading && !hasPages
+		progressBar_bottom.isVisible = isLoading && hasPages
 	}
 
 	override fun onError(e: Exception) {
@@ -177,15 +184,11 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 			}
 			GridTouchHelper.AREA_TOP,
 			GridTouchHelper.AREA_LEFT -> {
-				reader?.let {
-					it.setCurrentPage(it.currentPageIndex - 1, true)
-				}
+				reader?.switchPageBy(-1)
 			}
 			GridTouchHelper.AREA_BOTTOM,
 			GridTouchHelper.AREA_RIGHT -> {
-				reader?.let {
-					it.setCurrentPage(it.currentPageIndex + 1, true)
-				}
+				reader?.switchPageBy(1)
 			}
 		}
 	}
@@ -225,7 +228,7 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 
 	override fun onReaderModeChanged(mode: ReaderMode) {
 		reader?.let {
-			state = state.copy(page = it.currentPageIndex)
+			state = state.copy(page = it.findCurrentPageIndex(state.chapterId))
 		}
 		presenter.saveState(state, mode)
 		setReader(mode)
@@ -248,10 +251,14 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 	}
 
 	override fun onPageChanged(chapter: MangaChapter, page: Int, total: Int) {
-		title = chapter.name
-		state.manga.chapters?.run {
-			supportActionBar?.subtitle =
-				getString(R.string.chapter_d_of_d, chapter.number, size)
+		if (chapter.id != state.chapterId) {
+			title = chapter.name
+			state = state.copy(chapterId = chapter.id)
+			presenter.saveState(state)
+			state.manga.chapters?.run {
+				supportActionBar?.subtitle =
+					getString(R.string.chapter_d_of_d, chapter.number, size)
+			}
 		}
 	}
 

app/src/main/java/org/koitharu/kotatsu/ui/reader/standard/StandardReaderFragment.kt

@@ -49,7 +49,11 @@ class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_stand
 					}
 				}
 			}
-			Action.PREPEND -> adapter?.prependData(pages)
+			Action.PREPEND -> adapter?.run {
+				val pos = pager.currentItem
+				prependData(pages)
+				pager.setCurrentItem(pos + pages.size, false)
+			}
 			Action.APPEND -> adapter?.appendData(pages)
 		}
 	}

app/src/main/java/org/koitharu/kotatsu/ui/reader/wetoon/WebtoonReaderFragment.kt

@@ -10,6 +10,7 @@ import org.koitharu.kotatsu.ui.reader.BaseReaderFragment
 import org.koitharu.kotatsu.ui.reader.OnBoundsScrollListener
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.ReaderPresenter
+import org.koitharu.kotatsu.utils.ext.doOnCurrentItemChanged
 import org.koitharu.kotatsu.utils.ext.firstItem
 
 class WebtoonReaderFragment : BaseReaderFragment(R.layout.fragment_reader_webtoon),
@@ -30,6 +31,7 @@ class WebtoonReaderFragment : BaseReaderFragment(R.layout.fragment_reader_webtoo
 		adapter = WebtoonAdapter(loader)
 		recyclerView.adapter = adapter
 		recyclerView.addOnScrollListener(ListPaginationListener(2, this))
+		recyclerView.doOnCurrentItemChanged(::notifyPageChanged)
 	}
 
 	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>, action: Action) {

app/src/main/java/org/koitharu/kotatsu/utils/ext/ViewExt.kt

@@ -172,4 +172,21 @@ fun ViewPager2.doOnPageChanged(callback: (Int) -> Unit) {
 			callback(position)
 		}
 	})
+}
+
+fun RecyclerView.doOnCurrentItemChanged(callback: (Int) -> Unit) {
+	addOnScrollListener(object : RecyclerView.OnScrollListener() {
+
+		private var lastItem = -1
+
+		override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
+			super.onScrolled(recyclerView, dx, dy)
+			val item = (recyclerView.layoutManager as? LinearLayoutManager)
+				?.findFirstVisibleItemPosition()
+			if (item != null && item != RecyclerView.NO_POSITION && item != lastItem) {
+				lastItem = item
+				callback(item)
+			}
+		}
+	})
 }

app/src/main/res/layout/activity_reader.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<com.google.android.material.circularreveal.CircularRevealFrameLayout
+<FrameLayout
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	android:id="@+id/rootLayout"
@@ -12,6 +12,15 @@
 		android:layout_width="match_parent"
 		android:layout_height="match_parent" />
 
+	<ProgressBar
+		android:id="@+id/progressBar_bottom"
+		android:layout_width="match_parent"
+		android:layout_height="wrap_content"
+		android:indeterminate="true"
+		android:layout_gravity="bottom"
+		android:layout_marginBottom="20dp"
+		style="@style/Widget.AppCompat.ProgressBar.Horizontal" />
+
 	<com.google.android.material.appbar.AppBarLayout
 		android:id="@+id/appbar_top"
 		android:layout_width="match_parent"
@@ -74,4 +83,4 @@
 
 	</LinearLayout>
 
-</com.google.android.material.circularreveal.CircularRevealFrameLayout>
+</FrameLayout>