From 4826ed0355e5ae0fa5936c6a7439accd695c44f3 Mon Sep 17 00:00:00 2001
From: davidoskky <davidoskky@yahoo.it>
Date: Wed, 2 Feb 2022 09:04:26 +0100
Subject: [PATCH] Scroll articles using the volume keys (#401)

---
 CHANGELOG.md                                  |  2 ++
 .../bou/readerforselfoss/ReaderActivity.kt    | 20 ++++++++++++++++++-
 .../fragments/ArticleFragment.kt              | 10 ++++++++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 06602aa..a87b03b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -48,6 +48,8 @@
 
 - Dropped support for android 4, the last version supporting it is v1721030811
 
+- Added ability to scroll articles up and down using the volume keys #400
+
 **1.6.x**
 
 - Handling hidden tags.
diff --git a/app/src/main/java/apps/amine/bou/readerforselfoss/ReaderActivity.kt b/app/src/main/java/apps/amine/bou/readerforselfoss/ReaderActivity.kt
index 6982409..b68dce5 100644
--- a/app/src/main/java/apps/amine/bou/readerforselfoss/ReaderActivity.kt
+++ b/app/src/main/java/apps/amine/bou/readerforselfoss/ReaderActivity.kt
@@ -4,6 +4,7 @@ import android.content.Context
 import android.content.SharedPreferences
 import android.graphics.Color
 import android.os.Bundle
+import android.view.KeyEvent
 import androidx.preference.PreferenceManager
 import androidx.appcompat.app.AppCompatActivity
 import android.view.Menu
@@ -135,13 +136,30 @@ class ReaderActivity : AppCompatActivity() {
     private inner class ScreenSlidePagerAdapter(fa: FragmentActivity) :
         FragmentStateAdapter(fa) {
 
-
         override fun getItemCount(): Int = allItems.size
 
         override fun createFragment(position: Int): Fragment = ArticleFragment.newInstance(allItems[position])
 
     }
 
+    override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
+        return when (keyCode) {
+            KeyEvent.KEYCODE_VOLUME_DOWN -> {
+                val currentFragment = supportFragmentManager.findFragmentByTag("f" + binding.pager.currentItem) as ArticleFragment
+                currentFragment.scrollDown()
+                true
+            }
+            KeyEvent.KEYCODE_VOLUME_UP -> {
+                val currentFragment = supportFragmentManager.findFragmentByTag("f" + binding.pager.currentItem) as ArticleFragment
+                currentFragment.scrollUp()
+                true
+            }
+            else -> {
+                super.onKeyDown(keyCode, event)
+            }
+        }
+    }
+
     private fun alignmentMenu(showJustify: Boolean) {
         toolbarMenu.findItem(R.id.align_left).isVisible = !showJustify
         toolbarMenu.findItem(R.id.align_justify).isVisible = showJustify
diff --git a/app/src/main/java/apps/amine/bou/readerforselfoss/fragments/ArticleFragment.kt b/app/src/main/java/apps/amine/bou/readerforselfoss/fragments/ArticleFragment.kt
index 6e84e23..ef011ea 100644
--- a/app/src/main/java/apps/amine/bou/readerforselfoss/fragments/ArticleFragment.kt
+++ b/app/src/main/java/apps/amine/bou/readerforselfoss/fragments/ArticleFragment.kt
@@ -511,6 +511,16 @@ class ArticleFragment : Fragment() {
         )
     }
 
+    fun scrollDown() {
+        val height = binding.nestedScrollView.measuredHeight
+        binding.nestedScrollView.smoothScrollBy(0, height/2)
+    }
+
+    fun scrollUp() {
+        val height = binding.nestedScrollView.measuredHeight
+        binding.nestedScrollView.smoothScrollBy(0, -height/2)
+    }
+
     private fun openInBrowserAfterFailing(customTabsIntent: CustomTabsIntent) {
         binding.progressBar.visibility = View.GONE
         requireActivity().openItemUrlInternalBrowser(