Reader : Take manual scroll into account during vertical auto-scroll [#1180]

Author: RobbWatershed

app/src/main/java/me/devsaki/hentoid/activities/AboutActivity.kt

@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.View
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.commit
+import androidx.lifecycle.lifecycleScope
 import androidx.recyclerview.widget.RecyclerView
 import com.mikepenz.aboutlibraries.Libs
 import com.mikepenz.aboutlibraries.LibsBuilder
@@ -55,7 +56,8 @@ class AboutActivity : BaseActivity() {
                     recyclerView.setBackgroundColor(
                         getThemedColor(R.color.window_background_light)
                     )
-                    val scrollListener = ScrollPositionListener { _ -> /* Nothing */ }
+                    val scrollListener =
+                        ScrollPositionListener(lifecycleScope) { _ -> /* Nothing */ }
                     scrollListener.setOnEndOutOfBoundScrollListener {
                         AchievementsManager.trigger(16)
                     }

app/src/main/java/me/devsaki/hentoid/fragments/library/LibraryContentFragment.kt

@@ -164,7 +164,8 @@ class LibraryContentFragment : Fragment(), ChangeGroupDialogFragment.Parent,
     private var llm: LinearLayoutManager? = null
 
     // Scroll listener for the top FAB
-    private val scrollListener = ScrollPositionListener { i -> onScrollPositionChange(i) }
+    private val scrollListener =
+        ScrollPositionListener(lifecycleScope) { i -> onScrollPositionChange(i) }
 
     // === FASTADAPTER COMPONENTS AND HELPERS
     private var itemAdapter: ItemAdapter<ContentItem>? = null
@@ -357,7 +358,7 @@ class LibraryContentFragment : Fragment(), ChangeGroupDialogFragment.Parent,
 
         // Hide FAB when scrolling up
         binding?.topFab?.apply {
-            scrollListener.setDeltaYListener(lifecycleScope) { i: Int ->
+            scrollListener.setDeltaYListener { i: Int ->
                 isVisible = (Settings.topFabEnabled && i > 0)
             }
 
@@ -1148,7 +1149,10 @@ class LibraryContentFragment : Fragment(), ChangeGroupDialogFragment.Parent,
                     calledFromOnStart: Boolean
                 ) {
                     selectExtension?.let { se ->
-                        if (isSelected) IntRange(start, end).forEach { se.select(it, false, true) }
+                        if (isSelected) IntRange(start, end).forEach { se.select(it,
+                            fireEvent = false,
+                            considerSelectableFlag = true
+                        ) }
                         else se.deselect(IntRange(start, end).toMutableList())
                     }
                 }

app/src/main/java/me/devsaki/hentoid/fragments/reader/ReaderPagerFragment.kt

@@ -121,7 +121,8 @@ class ReaderPagerFragment : Fragment(R.layout.fragment_reader_pager),
     var reachedPosition = -1
 
     private var hasGalleryBeenShown = false
-    override val scrollListener = ScrollPositionListener { onScrollPositionChange(it) }
+    override val scrollListener =
+        ScrollPositionListener(lifecycleScope) { onScrollPositionChange(it) }
     private var orientation = DeviceOrientation.PORTRAIT
 
     override var displayParams: DisplayParams? = null
@@ -491,6 +492,8 @@ class ReaderPagerFragment : Fragment(R.layout.fragment_reader_pager),
             slideshowMgr = ReaderSlideshow(this, lifecycleScope)
             slideshowMgr.init(it, this.resources)
 
+            scrollListener.setAbsYListener { slideshowMgr.onManualScrollY() }
+
             // Fix page button
             it.viewerFixBtn.setOnClickListener { fixPage() }
 

app/src/main/java/me/devsaki/hentoid/fragments/reader/ReaderSlideshow.kt

@@ -54,6 +54,8 @@ class ReaderSlideshow(private val pager: Pager, lifecycleScope: LifecycleCorouti
 
     private var hasGoneBack = false
 
+    private var autoScrollFactor = 1f
+
     // Debouncer for the slideshow slider
     private val slideshowSliderDebouncer: Debouncer<Int>
 
@@ -227,21 +229,26 @@ class ReaderSlideshow(private val pager: Pager, lifecycleScope: LifecycleCorouti
     }
 
     private fun activateAutoScroll(factor: Float = -1f) {
-        val theFactor = if (factor < 0) {
+        autoScrollFactor = if (factor < 0) {
             val scrollParams = getScrollParams()
             scrollParams.second
         } else factor
 
-        // Create a a specific ReaderSmoothScroller to perform vertical slideshow (=auto-scroll)
+        // Create a specific ReaderSmoothScroller to perform vertical slideshow (=auto-scroll)
         // Mandatory; if we don't recreate it, we can't change scrolling speed as it is cached internally
-        val smoothScroller = ReaderSmoothScroller(controlsOverlay!!.root.context)
-        smoothScroller.apply {
+        ReaderSmoothScroller(controlsOverlay!!.root.context).apply {
             setCurrentPositionY(pager.scrollListener.totalScrolledY)
             setItemHeight(pager.adapter.getDimensionsAtPosition(pager.absImageIndex).y)
             targetPosition = pager.adapter.itemCount - 1
-            setSpeed(900f / (theFactor / 4f))
+            setSpeed(900f / (autoScrollFactor / 4f))
+            pager.setAndStartSmoothScroll(this)
         }
-        pager.setAndStartSmoothScroll(smoothScroller)
+    }
+
+    fun onManualScrollY() {
+        if (!isSlideshowActive) return
+        if (VIEWER_ORIENTATION_VERTICAL != pager.displayParams?.orientation) return
+        activateAutoScroll(autoScrollFactor)
     }
 
     private fun onSlideshowTick() {

app/src/main/java/me/devsaki/hentoid/widget/ReaderSmoothScroller.kt

@@ -23,7 +23,7 @@ class ReaderSmoothScroller(context: Context) : LinearSmoothScroller(context) {
     }
 
     fun setSpeed(speed: Float) {
-        Timber.i("SPEED : %s", speed)
+        Timber.d("SPEED : $speed")
         this.speed = speed
     }
 
@@ -61,7 +61,7 @@ class ReaderSmoothScroller(context: Context) : LinearSmoothScroller(context) {
         mInterimTargetDy = scrollVector.y.toInt()
         val time = calculateTimeForScrolling(mInterimTargetDy)
         // To avoid UI hiccups, trigger a smooth scroll to a distance little further than the
-        // interim target. Since we track the distance travelled in onSeekTargetStep callback, it
+        // interim target. Since we track the distance traveled in onSeekTargetStep callback, it
         // won't actually scroll more than what we need.
         action.update(mInterimTargetDx, mInterimTargetDy, time, mLinearInterpolator)
     }

app/src/main/java/me/devsaki/hentoid/widget/ScrollPositionListener.kt

@@ -1,11 +1,15 @@
 package me.devsaki.hentoid.widget
 
+import androidx.core.util.Consumer
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import kotlinx.coroutines.CoroutineScope
 import me.devsaki.hentoid.util.Debouncer
 
-class ScrollPositionListener(private val onPositionChangeListener: (Int) -> Unit) :
+class ScrollPositionListener(
+    scope: CoroutineScope,
+    private val onPositionChangeListener: (Int) -> Unit
+) :
     RecyclerView.OnScrollListener() {
     private var isScrollEnabled = true
 
@@ -24,19 +28,31 @@ class ScrollPositionListener(private val onPositionChangeListener: (Int) -> Unit
 
     private var deltaEventDebouncer: Debouncer<Int>? = null
 
+    private var onScrollYDelta: Consumer<Int>? = null
+    private var onScrollYAbs: Consumer<Int>? = null
+
     private var onPositionReachedListener: ((Int) -> Unit)? = null
 
     private var onStartOutOfBoundScroll: Runnable? = null
     private var onEndOutOfBoundScroll: Runnable? = null
 
 
-    fun setDeltaYListener(scope: CoroutineScope, deltaYListener: (Int) -> Unit) {
-        deltaEventDebouncer = Debouncer(scope, 75) { i: Int ->
-            deltaYListener.invoke(i - mInitialOffsetY)
+    init {
+        deltaEventDebouncer = Debouncer(scope, 75) { absY: Int ->
+            onScrollYAbs?.accept(absY)
+            onScrollYDelta?.accept(absY - mInitialOffsetY)
             mInitialOffsetY = -1
         }
     }
 
+    fun setDeltaYListener(deltaYListener: Consumer<Int>) {
+        onScrollYDelta = deltaYListener
+    }
+
+    fun setAbsYListener(absYListener: Consumer<Int>) {
+        onScrollYAbs = absYListener
+    }
+
     fun setOnStartOutOfBoundScrollListener(onStartOutOfBoundScrollListener: Runnable?) {
         onStartOutOfBoundScroll = onStartOutOfBoundScrollListener
     }