Fix reader state saving

app/src/main/java/org/koitharu/kotatsu/ui/common/list/BaseRecyclerAdapter.kt

@@ -49,6 +49,12 @@ abstract class BaseRecyclerAdapter<T, E>(private val onItemClickListener: OnRecy
 		onDataSetChanged()
 	}
 
+	fun prependData(newData: List<T>) {
+		dataSet.addAll(0, newData)
+		notifyItemRangeInserted(0, newData.size)
+		onDataSetChanged()
+	}
+
 	fun appendItem(newItem: T) {
 		dataSet.add(newItem)
 		notifyItemInserted(dataSet.lastIndex)

app/src/main/java/org/koitharu/kotatsu/ui/common/list/BoundsScrollListener.kt

@@ -13,7 +13,7 @@ abstract class BoundsScrollListener(private val offsetTop: Int, private val offs
 		val layoutManager = (recyclerView.layoutManager as? LinearLayoutManager) ?: return
 		val firstVisibleItemPosition = layoutManager.findFirstVisibleItemPosition()
 		if (firstVisibleItemPosition <= offsetTop) {
-			onScrolledToTop(recyclerView)
+			onScrolledToStart(recyclerView)
 			return
 		}
 		val visibleItemCount = layoutManager.childCount
@@ -23,7 +23,7 @@ abstract class BoundsScrollListener(private val offsetTop: Int, private val offs
 		}
 	}
 
-	abstract fun onScrolledToTop(recyclerView: RecyclerView)
+	abstract fun onScrolledToStart(recyclerView: RecyclerView)
 
 	abstract fun onScrolledToEnd(recyclerView: RecyclerView)
 }

app/src/main/java/org/koitharu/kotatsu/ui/common/list/PaginationScrollListener.kt

@@ -6,7 +6,7 @@ class PaginationScrollListener(offset: Int, private val callback: Callback) : Bo
 
 	private var lastTotalCount = 0
 
-	override fun onScrolledToTop(recyclerView: RecyclerView)  = Unit
+	override fun onScrolledToStart(recyclerView: RecyclerView)  = Unit
 
 	override fun onScrolledToEnd(recyclerView: RecyclerView) {
 		val total = recyclerView.adapter?.itemCount ?: 0

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

@@ -2,10 +2,16 @@ package org.koitharu.kotatsu.ui.reader
 
 import android.net.Uri
 import androidx.annotation.LayoutRes
+import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.core.model.MangaPage
+import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.ui.common.BaseFragment
 
-abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragment(contentLayoutId), ReaderView {
+abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragment(contentLayoutId),
+	ReaderView {
+
+	protected val lastState
+		get() = (activity as? ReaderActivity)?.state
 
 	abstract val hasItems: Boolean
 
@@ -31,4 +37,9 @@ abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragmen
 	 * Handled by activity
 	 */
 	override fun onPageSaved(uri: Uri?) = Unit
+
+
+	override fun onInitReader(mode: ReaderMode) = Unit
+
+	override fun onChaptersLoader(chapters: List<MangaChapter>) = Unit
 }

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

@@ -15,6 +15,7 @@ import androidx.core.view.updatePadding
 import androidx.fragment.app.commit
 import com.google.android.material.snackbar.Snackbar
 import kotlinx.android.synthetic.main.activity_reader.*
+import moxy.MvpDelegate
 import moxy.ktx.moxyPresenter
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.model.Manga
@@ -37,7 +38,8 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 
 	private val presenter by moxyPresenter(factory = ReaderPresenter.Companion::getInstance)
 
-	private lateinit var state: ReaderState
+	lateinit var state: ReaderState
+		private set
 
 	private lateinit var touchHelper: GridTouchHelper
 
@@ -71,25 +73,19 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 			insets
 		}
 
-		presenter.loadChapter(state)
-	}
-
-	override fun onInitReader(pages: List<MangaPage>, mode: ReaderMode, state: ReaderState) {
-		val currentReader = reader
-		when (mode) {
-			ReaderMode.WEBTOON -> if (currentReader !is WebtoonReaderFragment) {
-				supportFragmentManager.commit {
-					replace(R.id.container, WebtoonReaderFragment())
-				}
-			}
-			else -> if (currentReader !is StandardReaderFragment) {
-				supportFragmentManager.commit {
-					replace(R.id.container, StandardReaderFragment())
-				}
-			}
+		if (savedInstanceState?.containsKey(MvpDelegate.MOXY_DELEGATE_TAGS_KEY) != true) {
+			presenter.loadChapter(state.manga, state.chapterId)
 		}
 	}
 
+	override fun onInitReader(mode: ReaderMode) {
+		if (reader == null) {
+			setReader(mode)
+		}
+	}
+
+	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>) = Unit
+
 	override fun onPause() {
 		reader?.let {
 			state = state.copy(page = it.currentPageIndex)
@@ -176,15 +172,7 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 	override fun onGridTouch(area: Int) {
 		when (area) {
 			GridTouchHelper.AREA_CENTER -> {
-				if (appbar_top.isVisible) {
-					appbar_top.hideAnimated(Motion.SlideTop)
-					appbar_bottom.hideAnimated(Motion.SlideBottom)
-					hideSystemUI()
-				} else {
-					appbar_top.showAnimated(Motion.SlideTop)
-					appbar_bottom.showAnimated(Motion.SlideBottom)
-					showSystemUI()
-				}
+				setUiIsVisible(!appbar_top.isVisible)
 			}
 			GridTouchHelper.AREA_TOP,
 			GridTouchHelper.AREA_LEFT -> {
@@ -222,7 +210,7 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 			chapterId = chapter.id,
 			page = 0
 		)
-		presenter.loadChapter(state)
+		presenter.loadChapter(state.manga, chapter.id)
 	}
 
 	override fun onPageSelected(page: MangaPage) {
@@ -239,7 +227,12 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 			state = state.copy(page = it.currentPageIndex)
 		}
 		presenter.saveState(state, mode)
-		recreate()
+		setReader(mode)
+		setUiIsVisible(false)
+	}
+
+	override fun onChaptersLoader(chapters: List<MangaChapter>) {
+		state = state.copy(manga = state.manga.copy(chapters = chapters))
 	}
 
 	override fun onPageSaved(uri: Uri?) {
@@ -259,6 +252,36 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 		}.show()
 	}
 
+	private fun setUiIsVisible(isUiVisible: Boolean) {
+		if (appbar_top.isVisible != isUiVisible) {
+			if (isUiVisible) {
+				appbar_top.showAnimated(Motion.SlideTop)
+				appbar_bottom.showAnimated(Motion.SlideBottom)
+				showSystemUI()
+			} else {
+				appbar_top.hideAnimated(Motion.SlideTop)
+				appbar_bottom.hideAnimated(Motion.SlideBottom)
+				hideSystemUI()
+			}
+		}
+	}
+
+	private fun setReader(mode: ReaderMode) {
+		val currentReader = reader
+		when (mode) {
+			ReaderMode.WEBTOON -> if (currentReader !is WebtoonReaderFragment) {
+				supportFragmentManager.commit {
+					replace(R.id.container, WebtoonReaderFragment())
+				}
+			}
+			else -> if (currentReader !is StandardReaderFragment) {
+				supportFragmentManager.commit {
+					replace(R.id.container, StandardReaderFragment())
+				}
+			}
+		}
+	}
+
 	companion object {
 
 		private const val EXTRA_STATE = "state"

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

@@ -11,6 +11,7 @@ import moxy.presenterScope
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import org.koitharu.kotatsu.BuildConfig
+import org.koitharu.kotatsu.core.model.Manga
 import org.koitharu.kotatsu.core.model.MangaPage
 import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.domain.MangaPreferencesRepository
@@ -26,29 +27,42 @@ import org.koitharu.kotatsu.utils.ext.mimeType
 @InjectViewState
 class ReaderPresenter : BasePresenter<ReaderView>() {
 
-	fun loadChapter(state: ReaderState) {
+	private var isInitialized = false
+
+	fun loadChapter(manga: Manga, chapterId: Long) {
 		presenterScope.launch {
 			viewState.onLoadingStateChanged(isLoading = true)
 			try {
-				val (pages, mode) = withContext(Dispatchers.IO) {
-					val repo = MangaProviderFactory.create(state.manga.source)
-					val chapter = state.chapter ?: repo.getDetails(state.manga).chapters
-						?.first { it.id == state.chapterId }
-					?: throw RuntimeException("Chapter ${state.chapterId} not found")
-					var mode = MangaPreferencesRepository().getReaderMode(state.manga.id)
-					val pages = repo.getPages(chapter)
-					if (mode == null) {
-						mode = MangaUtils.determineReaderMode(pages)
-						if (mode != null) {
-							MangaPreferencesRepository().saveData(
-								mangaId = state.manga.id,
-								mode = mode
-							)
+				withContext(Dispatchers.IO) {
+					val repo = MangaProviderFactory.create(manga.source)
+					val chapter = (manga.chapters ?: repo.getDetails(manga).chapters?.also {
+						withContext(Dispatchers.Main) {
+							viewState.onChaptersLoader(it)
 						}
+					})?.find { it.id == chapterId }
+						?: throw RuntimeException("Chapter ${chapterId} not found")
+					val pages = repo.getPages(chapter)
+					if (!isInitialized) {
+						val prefs = MangaPreferencesRepository()
+						var mode = prefs.getReaderMode(manga.id)
+						if (mode == null) {
+							mode = MangaUtils.determineReaderMode(pages)
+							if (mode != null) {
+								prefs.saveData(
+									mangaId = manga.id,
+									mode = mode
+								)
+							}
+						}
+						withContext(Dispatchers.Main) {
+							viewState.onInitReader(mode ?: ReaderMode.UNKNOWN)
+						}
+						isInitialized = true
+					}
+					withContext(Dispatchers.Main) {
+						viewState.onPagesLoaded(chapterId, pages)
 					}
-					pages to (mode ?: ReaderMode.UNKNOWN)
 				}
-				viewState.onInitReader(pages, mode, state)
 			} catch (e: Exception) {
 				if (BuildConfig.DEBUG) {
 					e.printStackTrace()

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

@@ -4,13 +4,20 @@ import android.net.Uri
 import moxy.MvpView
 import moxy.viewstate.strategy.alias.AddToEndSingle
 import moxy.viewstate.strategy.alias.OneExecution
+import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.core.model.MangaPage
 import org.koitharu.kotatsu.core.prefs.ReaderMode
 
 interface ReaderView : MvpView {
 
 	@AddToEndSingle
-	fun onInitReader(pages: List<MangaPage>, mode: ReaderMode, state: ReaderState)
+	fun onInitReader(mode: ReaderMode)
+
+	@AddToEndSingle
+	fun onChaptersLoader(chapters: List<MangaChapter>)
+
+	@AddToEndSingle
+	fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>)
 
 	@AddToEndSingle
 	fun onLoadingStateChanged(isLoading: Boolean)

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

@@ -6,17 +6,16 @@ import kotlinx.android.synthetic.main.fragment_reader_standard.*
 import moxy.ktx.moxyPresenter
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.model.MangaPage
-import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.ui.reader.BaseReaderFragment
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.ReaderPresenter
-import org.koitharu.kotatsu.ui.reader.ReaderState
 
 class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_standard) {
 
 	private val presenter by moxyPresenter(factory = ReaderPresenter.Companion::getInstance)
 
 	private var adapter: PagesAdapter? = null
+	private var isBusy: Boolean = true
 	private lateinit var loader: PageLoader
 
 	override fun onCreate(savedInstanceState: Bundle?) {
@@ -31,11 +30,21 @@ class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_stand
 		pager.offscreenPageLimit = 2
 	}
 
-	override fun onInitReader(pages: List<MangaPage>, mode: ReaderMode, state: ReaderState) {
+	override fun onDestroyView() {
+		adapter = null
+		super.onDestroyView()
+	}
+
+	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>) {
 		adapter?.let {
 			it.replaceData(pages)
-			pager.setCurrentItem(state.page, false)
+			lastState?.let { state ->
+				if (chapterId == state.chapterId) {
+					pager.setCurrentItem(state.page, false)
+				}
+			}
 		}
+		isBusy = false
 	}
 
 	override fun onDestroy() {
@@ -55,4 +64,9 @@ class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_stand
 	override fun setCurrentPage(index: Int, smooth: Boolean) {
 		pager.setCurrentItem(index, smooth)
 	}
+
+	private companion object {
+
+		const val SCROLL_OFFSET = 2
+	}
 }

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

@@ -6,11 +6,9 @@ import kotlinx.android.synthetic.main.fragment_reader_webtoon.*
 import moxy.ktx.moxyPresenter
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.model.MangaPage
-import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.ui.reader.BaseReaderFragment
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.ReaderPresenter
-import org.koitharu.kotatsu.ui.reader.ReaderState
 import org.koitharu.kotatsu.utils.ext.firstItem
 
 class WebtoonReaderFragment : BaseReaderFragment(R.layout.fragment_reader_webtoon) {
@@ -31,10 +29,14 @@ class WebtoonReaderFragment : BaseReaderFragment(R.layout.fragment_reader_webtoo
 		recyclerView.adapter = adapter
 	}
 
-	override fun onInitReader(pages: List<MangaPage>, mode: ReaderMode, state: ReaderState) {
+	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>) {
 		adapter?.let {
 			it.replaceData(pages)
-			recyclerView.firstItem = state.page
+			lastState?.let { state ->
+				if (chapterId == state.chapterId) {
+					recyclerView.firstItem = state.page
+				}
+			}
 		}
 	}
 

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

@@ -18,6 +18,7 @@ import androidx.drawerlayout.widget.DrawerLayout
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
+import androidx.viewpager2.widget.ViewPager2
 import com.google.android.material.chip.Chip
 import com.google.android.material.chip.ChipGroup
 import org.koitharu.kotatsu.ui.common.ChipsFactory
@@ -102,7 +103,10 @@ fun View.disableFor(timeInMillis: Long) {
 	}
 }
 
-fun View.showPopupMenu(@MenuRes menuRes: Int, onPrepare:((Menu) -> Unit)? = null, onItemClick: (MenuItem) -> Boolean) {
+fun View.showPopupMenu(
+	@MenuRes menuRes: Int, onPrepare: ((Menu) -> Unit)? = null,
+	onItemClick: (MenuItem) -> Boolean
+) {
 	val menu = PopupMenu(context, this)
 	menu.inflate(menuRes)
 	menu.setOnMenuItemClickListener(onItemClick)
@@ -159,3 +163,13 @@ fun View.measureWidth(): Int {
 		measuredWidth
 	} else vw
 }
+
+fun ViewPager2.doOnPageChanged(callback: (Int) -> Unit) {
+	registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
+
+		override fun onPageSelected(position: Int) {
+			super.onPageSelected(position)
+			callback(position)
+		}
+	})
+}