From 049f32d2f0bd7193fc44d1ebe73ef93b43e89709 Mon Sep 17 00:00:00 2001
From: Koitharu <nvasya95@gmail.com>
Date: Sun, 21 Mar 2021 18:33:13 +0200
Subject: [PATCH] Fix smooth page switching

---
 .../ui/pager/reversed/ReversedReaderFragment.kt       |  7 ++++++-
 .../reader/ui/pager/standard/PagerReaderFragment.kt   | 11 ++++++++++-
 .../reader/ui/pager/wetoon/WebtoonReaderFragment.kt   |  6 +-----
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/reversed/ReversedReaderFragment.kt b/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/reversed/ReversedReaderFragment.kt
index a0ffe4678..9da14c353 100644
--- a/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/reversed/ReversedReaderFragment.kt
+++ b/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/reversed/ReversedReaderFragment.kt
@@ -12,7 +12,9 @@ import org.koitharu.kotatsu.reader.ui.ReaderState
 import org.koitharu.kotatsu.reader.ui.pager.BaseReader
 import org.koitharu.kotatsu.reader.ui.pager.BaseReaderAdapter
 import org.koitharu.kotatsu.reader.ui.pager.ReaderPage
+import org.koitharu.kotatsu.reader.ui.pager.standard.PagerReaderFragment
 import org.koitharu.kotatsu.utils.ext.*
+import kotlin.math.absoluteValue
 
 class ReversedReaderFragment : BaseReader<FragmentReaderStandardBinding>() {
 
@@ -58,7 +60,10 @@ class ReversedReaderFragment : BaseReader<FragmentReaderStandardBinding>() {
 	}
 
 	override fun switchPageTo(position: Int, smooth: Boolean) {
-		binding.pager.setCurrentItem(reversed(position), smooth)
+		binding.pager.setCurrentItem(
+			reversed(position),
+			smooth && (binding.pager.currentItem - position).absoluteValue < PagerReaderFragment.SMOOTH_SCROLL_LIMIT
+		)
 	}
 
 	override fun onPagesChanged(pages: List<ReaderPage>, pendingState: ReaderState?) {
diff --git a/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/standard/PagerReaderFragment.kt b/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/standard/PagerReaderFragment.kt
index 42758bdf3..c93a27ef0 100644
--- a/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/standard/PagerReaderFragment.kt
+++ b/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/standard/PagerReaderFragment.kt
@@ -13,6 +13,7 @@ import org.koitharu.kotatsu.reader.ui.pager.BaseReader
 import org.koitharu.kotatsu.reader.ui.pager.BaseReaderAdapter
 import org.koitharu.kotatsu.reader.ui.pager.ReaderPage
 import org.koitharu.kotatsu.utils.ext.*
+import kotlin.math.absoluteValue
 
 class PagerReaderFragment : BaseReader<FragmentReaderStandardBinding>() {
 
@@ -78,7 +79,10 @@ class PagerReaderFragment : BaseReader<FragmentReaderStandardBinding>() {
 	}
 
 	override fun switchPageTo(position: Int, smooth: Boolean) {
-		binding.pager.setCurrentItem(position, smooth)
+		binding.pager.setCurrentItem(
+			position,
+			smooth && (binding.pager.currentItem - position).absoluteValue < SMOOTH_SCROLL_LIMIT
+		)
 	}
 
 	override fun getCurrentState(): ReaderState? = bindingOrNull()?.run {
@@ -94,4 +98,9 @@ class PagerReaderFragment : BaseReader<FragmentReaderStandardBinding>() {
 	private fun notifyPageChanged(page: Int) {
 		viewModel.onCurrentPageChanged(page)
 	}
+
+	companion object {
+
+		const val SMOOTH_SCROLL_LIMIT = 3
+	}
 }
\ No newline at end of file
diff --git a/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/wetoon/WebtoonReaderFragment.kt b/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/wetoon/WebtoonReaderFragment.kt
index d55aee42d..e1b1ab879 100644
--- a/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/wetoon/WebtoonReaderFragment.kt
+++ b/app/src/main/java/org/koitharu/kotatsu/reader/ui/pager/wetoon/WebtoonReaderFragment.kt
@@ -88,10 +88,6 @@ class WebtoonReaderFragment : BaseReader<FragmentReaderWebtoonBinding>() {
 	}
 
 	override fun switchPageTo(position: Int, smooth: Boolean) {
-		if (smooth) {
-			binding.recyclerView.smoothScrollToPosition(position)
-		} else {
-			binding.recyclerView.firstItem = position
-		}
+		binding.recyclerView.firstItem = position
 	}
 }
\ No newline at end of file