From 4c30813b7eda7291e37b1108b7bf0f4199e2e67d Mon Sep 17 00:00:00 2001
From: Pavel Tsekov <ptsekov@gmx.net>
Date: Mon, 8 Mar 2021 13:08:20 +0200
Subject: [PATCH] Fix arrow scroll

---
 .../loopingviewpager/widget/LoopingViewPager.kt | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/loopingviewpager/src/main/java/com/kenilt/loopingviewpager/widget/LoopingViewPager.kt b/loopingviewpager/src/main/java/com/kenilt/loopingviewpager/widget/LoopingViewPager.kt
index 13bba31..7093ea4 100644
--- a/loopingviewpager/src/main/java/com/kenilt/loopingviewpager/widget/LoopingViewPager.kt
+++ b/loopingviewpager/src/main/java/com/kenilt/loopingviewpager/widget/LoopingViewPager.kt
@@ -19,6 +19,7 @@ class LoopingViewPager : ViewPager {
     private var originalAdapter: PagerAdapter? = null
     private var internalAdapter: PagerAdapter? = null
     private val pageChangeListenerMap = HashMap<OnPageChangeListener, InternalOnPageChangeListener>()
+    private var insideArrowScroll: Boolean = false
 
     constructor(context: Context) : super(context)
 
@@ -100,11 +101,16 @@ class LoopingViewPager : ViewPager {
     }
 
     override fun setCurrentItem(item: Int, smoothScroll: Boolean) {
+        // setCurrentItem() assumes it is passed an item position from the
+        // original adapter, however when it is invoked from within arrowScroll()
+        // it is passed an item position from the internal adapter, so the code
+        // should account for it.
+        val originalItem = if (insideArrowScroll) getPagerPosition(originalAdapter, item) else item
         val count = adapter?.count ?: 0
-        if (item == 0 && currentItem == count - 1) {
+        if (originalItem == 0 && currentItem == count - 1) {
             super.setCurrentItem(count + 2, smoothScroll)
         } else {
-            super.setCurrentItem(getInternalPosition(originalAdapter, item), smoothScroll)
+            super.setCurrentItem(getInternalPosition(originalAdapter, originalItem), smoothScroll)
         }
     }
 
@@ -123,6 +129,13 @@ class LoopingViewPager : ViewPager {
         }
     }
 
+    override fun arrowScroll(direction: Int): Boolean {
+        insideArrowScroll = true
+        val handled = super.arrowScroll(direction)
+        insideArrowScroll = false
+        return handled
+    }
+
     private fun handleSetCurrentItem(position: Int) {
         val itemCount = internalAdapter?.count ?: 0
         if (itemCount <= 1) return