Add more improved fast scroller

app/src/main/java/org/koitharu/kotatsu/base/ui/widgets/FastScrollRecyclerView.kt

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2022 Randy Webster. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.koitharu.kotatsu.base.ui.widgets
+
+import android.content.Context
+import android.util.AttributeSet
+import androidx.annotation.ColorInt
+import androidx.recyclerview.widget.RecyclerView
+import org.koitharu.kotatsu.R
+
+class FastScrollRecyclerView : RecyclerView {
+
+	private val fastScroller: FastScroller
+
+	constructor(context: Context) : super(context) {
+		fastScroller = context.layout()
+		layoutParams = LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT)
+	}
+
+	@JvmOverloads
+	constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int = 0) : super(context, attrs, defStyleAttr) {
+		fastScroller = context.layout(attrs)
+	}
+
+	override fun setAdapter(adapter: Adapter<*>?) = super.setAdapter(adapter).also {
+		when (adapter) {
+			is FastScroller.SectionIndexer -> fastScroller.setSectionIndexer(adapter)
+			null -> fastScroller.setSectionIndexer(null)
+		}
+	}
+
+	override fun setVisibility(visibility: Int) = super.setVisibility(visibility).also {
+		fastScroller.visibility = visibility
+	}
+
+	fun setFastScrollListener(fastScrollListener: FastScroller.FastScrollListener?) =
+		fastScroller.setFastScrollListener(fastScrollListener)
+
+	fun setFastScrollEnabled(enabled: Boolean) {
+		fastScroller.isEnabled = enabled
+	}
+
+	fun setHideScrollbar(hideScrollbar: Boolean) = fastScroller.setHideScrollbar(hideScrollbar)
+
+	fun setTrackVisible(visible: Boolean) = fastScroller.setTrackVisible(visible)
+
+	fun setTrackColor(@ColorInt color: Int) = fastScroller.setTrackColor(color)
+
+	fun setHandleColor(@ColorInt color: Int) = fastScroller.setHandleColor(color)
+
+	@JvmOverloads
+	fun setBubbleVisible(visible: Boolean, always: Boolean = false) = fastScroller.setBubbleVisible(visible, always)
+
+	fun setBubbleColor(@ColorInt color: Int) = fastScroller.setBubbleColor(color)
+
+	fun setBubbleTextColor(@ColorInt color: Int) = fastScroller.setBubbleTextColor(color)
+
+	fun setBubbleTextSize(size: Int) = fastScroller.setBubbleTextSize(size)
+
+	override fun onAttachedToWindow() = super.onAttachedToWindow().also {
+		fastScroller.attachRecyclerView(this)
+	}
+
+	override fun onDetachedFromWindow() {
+		fastScroller.detachRecyclerView()
+		super.onDetachedFromWindow()
+	}
+
+	private fun Context.layout(attrs: AttributeSet? = null) =
+		FastScroller(this, attrs).apply { id = R.id.fast_scroller }
+}

app/src/main/java/org/koitharu/kotatsu/base/ui/widgets/FastScroller.kt

@@ -0,0 +1,625 @@
+/*
+ * Copyright 2022 Randy Webster. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.koitharu.kotatsu.base.ui.widgets
+
+import android.animation.Animator
+import android.animation.AnimatorListenerAdapter
+import android.annotation.SuppressLint
+import android.content.Context
+import android.content.res.TypedArray
+import android.graphics.Color
+import android.graphics.drawable.Drawable
+import android.util.AttributeSet
+import android.util.TypedValue
+import android.view.MotionEvent
+import android.view.View
+import android.view.ViewGroup
+import android.view.ViewPropertyAnimator
+import android.widget.*
+import android.widget.RelativeLayout.*
+import androidx.annotation.ColorInt
+import androidx.annotation.DimenRes
+import androidx.annotation.DrawableRes
+import androidx.annotation.StyleableRes
+import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.constraintlayout.widget.ConstraintSet
+import androidx.coordinatorlayout.widget.CoordinatorLayout
+import androidx.core.content.withStyledAttributes
+import androidx.core.view.GravityCompat
+import androidx.core.view.isVisible
+import androidx.recyclerview.widget.RecyclerView
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
+import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.utils.ext.*
+import org.koitharu.kotatsu.utils.ext.getCompatDrawable
+import org.koitharu.kotatsu.utils.ext.isLayoutReversed
+import org.koitharu.kotatsu.utils.ext.setCompatTint
+import org.koitharu.kotatsu.utils.ext.wrap
+import kotlin.math.roundToInt
+
+private const val BUBBLE_ANIM_DURATION = 100L
+private const val SCROLLBAR_ANIM_DURATION = 300L
+private const val SCROLLBAR_HIDE_DELAY = 1000L
+private const val TRACK_SNAP_RANGE = 5
+
+@Suppress("MemberVisibilityCanBePrivate", "unused")
+class FastScroller : LinearLayout {
+
+	enum class Size(@DrawableRes val drawableId: Int, @DimenRes val textSizeId: Int) {
+		NORMAL(R.drawable.fastscroll_bubble, R.dimen.fastscroll_bubble_text_size),
+		SMALL(R.drawable.fastscroll_bubble_small, R.dimen.fastscroll_bubble_text_size_small)
+	}
+
+	private val Size.textSize get() = resources.getDimension(textSizeId)
+
+	private val bubbleView: TextView by lazy { findViewById(R.id.fastscroll_bubble) }
+	private val handleView: ImageView by lazy { findViewById(R.id.fastscroll_handle) }
+	private val trackView: ImageView by lazy { findViewById(R.id.fastscroll_track) }
+	private val scrollbar: View by lazy { findViewById(R.id.fastscroll_scrollbar) }
+
+	private val scrollbarPaddingEnd by lazy {
+		resources.getDimensionPixelSize(R.dimen.fastscroll_scrollbar_padding_end).toFloat()
+	}
+
+	@ColorInt
+	private var bubbleColor = 0
+	@ColorInt
+	private var handleColor = 0
+
+	private var bubbleHeight = 0
+	private var handleHeight = 0
+	private var viewHeight = 0
+	private var hideScrollbar = true
+	private var showBubble = true
+	private var showBubbleAlways = false
+	private var bubbleSize = Size.NORMAL
+	private var bubbleImage: Drawable? = null
+	private var handleImage: Drawable? = null
+	private var trackImage: Drawable? = null
+	private var recyclerView: RecyclerView? = null
+	private var swipeRefreshLayout: SwipeRefreshLayout? = null
+	private var scrollbarAnimator: ViewPropertyAnimator? = null
+	private var bubbleAnimator: ViewPropertyAnimator? = null
+
+	private var fastScrollListener: FastScrollListener? = null
+	private var sectionIndexer: SectionIndexer? = null
+
+	private val scrollbarHider = Runnable {
+		hideBubble()
+		hideScrollbar()
+	}
+
+	private val alphaAnimatorListener = object : AnimatorListenerAdapter() {
+		/* adapter required for new alpha value to stick */
+	}
+
+	private val scrollListener: RecyclerView.OnScrollListener = object : RecyclerView.OnScrollListener() {
+		override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
+			if (!handleView.isSelected && isEnabled) {
+				val y = recyclerView.scrollProportion
+				setViewPositions(y)
+
+				if (showBubbleAlways) {
+					val targetPos = getRecyclerViewTargetPosition(y)
+					sectionIndexer?.let { bubbleView.text = it.getSectionText(targetPos) }
+				}
+			}
+
+			swipeRefreshLayout?.let {
+				val firstVisibleItem = recyclerView.layoutManager.firstVisibleItemPosition
+				val topPosition = if (recyclerView.childCount == 0) 0 else recyclerView.getChildAt(0).top
+				it.isEnabled = firstVisibleItem == 0 && topPosition >= 0
+			}
+		}
+
+		override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
+			super.onScrollStateChanged(recyclerView, newState)
+
+			if (isEnabled) {
+				when (newState) {
+					RecyclerView.SCROLL_STATE_DRAGGING -> {
+						handler.removeCallbacks(scrollbarHider)
+						scrollbarAnimator?.cancel()
+
+						if (!scrollbar.isVisible) showScrollbar()
+						if (showBubbleAlways && sectionIndexer != null) showBubble()
+					}
+					RecyclerView.SCROLL_STATE_IDLE -> if (hideScrollbar && !handleView.isSelected) {
+						handler.postDelayed(scrollbarHider, SCROLLBAR_HIDE_DELAY)
+					}
+				}
+			}
+		}
+	}
+
+	private val RecyclerView.scrollProportion: Float
+		get() {
+			val rangeDiff = computeVerticalScrollRange() - computeVerticalScrollExtent()
+			val proportion = computeVerticalScrollOffset() / if (rangeDiff > 0) rangeDiff.toFloat() else 1f
+			return viewHeight * proportion
+		}
+
+	@JvmOverloads
+	constructor(context: Context, size: Size = Size.NORMAL) : super(context) {
+		context.layout(size = size)
+		layoutParams = LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT)
+	}
+
+	@JvmOverloads
+	constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int = 0) : super(context, attrs, defStyleAttr) {
+		context.layout(attrs)
+		layoutParams = attrs?.let { generateLayoutParams(it) } ?: LayoutParams(
+			LayoutParams.WRAP_CONTENT,
+			LayoutParams.MATCH_PARENT
+		)
+	}
+
+	override fun onSizeChanged(w: Int, h: Int, oldW: Int, oldH: Int) = super.onSizeChanged(w, h, oldW, oldH).also {
+		viewHeight = h
+	}
+
+	@SuppressLint("ClickableViewAccessibility")
+	override fun onTouchEvent(event: MotionEvent): Boolean {
+		val setYPositions: () -> Unit = {
+			val y = event.y
+			setViewPositions(y)
+			setRecyclerViewPosition(y)
+		}
+
+		when (event.action) {
+			MotionEvent.ACTION_DOWN -> {
+				if (event.x < handleView.x - scrollbar.compatPaddingStart) return false
+
+				requestDisallowInterceptTouchEvent(true)
+				setHandleSelected(true)
+
+				handler.removeCallbacks(scrollbarHider)
+				scrollbarAnimator?.cancel()
+				bubbleAnimator?.cancel()
+
+				if (!scrollbar.isVisible) showScrollbar()
+				if (showBubble && sectionIndexer != null) showBubble()
+
+				fastScrollListener?.onFastScrollStart(this)
+
+				setYPositions()
+				return true
+			}
+			MotionEvent.ACTION_MOVE -> {
+				setYPositions()
+				return true
+			}
+			MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
+				requestDisallowInterceptTouchEvent(false)
+				setHandleSelected(false)
+
+				if (hideScrollbar) handler.postDelayed(scrollbarHider, SCROLLBAR_HIDE_DELAY)
+				if (!showBubbleAlways) hideBubble()
+
+				fastScrollListener?.onFastScrollStop(this)
+
+				return true
+			}
+		}
+
+		return super.onTouchEvent(event)
+	}
+
+	/**
+	 * Set the enabled state of this view.
+	 *
+	 * @param enabled True if this view is enabled, false otherwise
+	 */
+	override fun setEnabled(enabled: Boolean) = super.setEnabled(enabled).also {
+		isVisible = enabled
+	}
+
+	/**
+	 * Set the [ViewGroup.LayoutParams] associated with this view. These supply
+	 * parameters to the *parent* of this view specifying how it should be arranged.
+	 *
+	 * @param params The [ViewGroup.LayoutParams] for this view, cannot be null
+	 */
+	override fun setLayoutParams(params: ViewGroup.LayoutParams) {
+		params.width = LayoutParams.WRAP_CONTENT
+		super.setLayoutParams(params)
+	}
+
+	/**
+	 * Set the [ViewGroup.LayoutParams] associated with this view. These supply
+	 * parameters to the *parent* of this view specifying how it should be arranged.
+	 *
+	 * @param viewGroup The parent [ViewGroup] for this view, cannot be null
+	 */
+	fun setLayoutParams(viewGroup: ViewGroup) {
+		val recyclerViewId = recyclerView?.id ?: NO_ID
+		val marginTop = resources.getDimensionPixelSize(R.dimen.fastscroll_scrollbar_margin_top)
+		val marginBottom = resources.getDimensionPixelSize(R.dimen.fastscroll_scrollbar_margin_bottom)
+
+		require(recyclerViewId != NO_ID) { "RecyclerView must have a view ID" }
+
+		when (viewGroup) {
+			is ConstraintLayout -> {
+				val endId = if (recyclerView?.parent === parent) recyclerViewId else ConstraintSet.PARENT_ID
+				val startId = id
+
+				ConstraintSet().apply {
+					clone(viewGroup)
+					connect(startId, ConstraintSet.TOP, endId, ConstraintSet.TOP)
+					connect(startId, ConstraintSet.BOTTOM, endId, ConstraintSet.BOTTOM)
+					connect(startId, ConstraintSet.END, endId, ConstraintSet.END)
+					applyTo(viewGroup)
+				}
+
+				layoutParams = (layoutParams as ConstraintLayout.LayoutParams).apply {
+					height = 0
+					setMargins(0, marginTop, 0, marginBottom)
+				}
+			}
+			is CoordinatorLayout -> layoutParams = (layoutParams as CoordinatorLayout.LayoutParams).apply {
+				height = LayoutParams.MATCH_PARENT
+				anchorGravity = GravityCompat.END
+				anchorId = recyclerViewId
+				setMargins(0, marginTop, 0, marginBottom)
+			}
+			is FrameLayout -> layoutParams = (layoutParams as FrameLayout.LayoutParams).apply {
+				height = LayoutParams.MATCH_PARENT
+				gravity = GravityCompat.END
+				setMargins(0, marginTop, 0, marginBottom)
+			}
+			is RelativeLayout -> layoutParams = (layoutParams as RelativeLayout.LayoutParams).apply {
+				height = 0
+				addRule(ALIGN_TOP, recyclerViewId)
+				addRule(ALIGN_BOTTOM, recyclerViewId)
+				addRule(ALIGN_END, recyclerViewId)
+				setMargins(0, marginTop, 0, marginBottom)
+			}
+			else -> throw IllegalArgumentException("Parent ViewGroup must be a ConstraintLayout, CoordinatorLayout, FrameLayout, or RelativeLayout")
+		}
+
+		updateViewHeights()
+	}
+
+	/**
+	 * Set the [RecyclerView] associated with this [FastScroller]. This allows the
+	 * FastScroller to set its layout parameters and listen for scroll changes.
+	 *
+	 * @param recyclerView The [RecyclerView] to attach, cannot be null
+	 * @see detachRecyclerView
+	 */
+	fun attachRecyclerView(recyclerView: RecyclerView) {
+		this.recyclerView = recyclerView
+
+		if (parent is ViewGroup) {
+			setLayoutParams(parent as ViewGroup)
+		} else if (recyclerView.parent is ViewGroup) {
+			val viewGroup = recyclerView.parent as ViewGroup
+			viewGroup.addView(this)
+			setLayoutParams(viewGroup)
+		}
+
+		recyclerView.addOnScrollListener(scrollListener)
+
+		// set initial positions for bubble and handle
+		post { setViewPositions(this.recyclerView?.scrollProportion ?: 0f) }
+	}
+
+	/**
+	 * Clears references to the attached [RecyclerView] and stops listening for scroll changes.
+	 *
+	 * @see attachRecyclerView
+	 */
+	fun detachRecyclerView() {
+		recyclerView?.removeOnScrollListener(scrollListener)
+		recyclerView = null
+	}
+
+	/**
+	 * Set a new [FastScrollListener] that will listen to fast scroll events.
+	 *
+	 * @param fastScrollListener The new [FastScrollListener] to set, or null to set none
+	 */
+	fun setFastScrollListener(fastScrollListener: FastScrollListener?) {
+		this.fastScrollListener = fastScrollListener
+	}
+
+	/**
+	 * Set a new [SectionIndexer] that provides section text for this [FastScroller].
+	 *
+	 * @param sectionIndexer The new [SectionIndexer] to set, or null to set none
+	 */
+	fun setSectionIndexer(sectionIndexer: SectionIndexer?) {
+		this.sectionIndexer = sectionIndexer
+	}
+
+	/**
+	 * Set a [SwipeRefreshLayout] to disable when the [RecyclerView] is scrolled away from the top.
+	 *
+	 * Required when SDK target precedes [VERSION_CODES.LOLLIPOP], otherwise use
+	 * [setNestedScrollingEnabled(true)][View.setNestedScrollingEnabled].
+	 *
+	 * @param swipeRefreshLayout The [SwipeRefreshLayout] to set, or null to set none
+	 */
+	fun setSwipeRefreshLayout(swipeRefreshLayout: SwipeRefreshLayout?) {
+		this.swipeRefreshLayout = swipeRefreshLayout
+	}
+
+	/**
+	 * Hide the scrollbar when not scrolling.
+	 *
+	 * @param hideScrollbar True to hide the scrollbar, false to show
+	 */
+	fun setHideScrollbar(hideScrollbar: Boolean) {
+		if (this.hideScrollbar != hideScrollbar) {
+			scrollbar.isVisible = !hideScrollbar.also { this.hideScrollbar = it }
+		}
+	}
+
+	/**
+	 * Show the scroll track while scrolling.
+	 *
+	 * @param visible True to show scroll track, false to hide
+	 */
+	fun setTrackVisible(visible: Boolean) {
+		trackView.isVisible = visible
+	}
+
+	/**
+	 * Set the color of the scroll track.
+	 *
+	 * @param color The color for the scroll track
+	 */
+	fun setTrackColor(@ColorInt color: Int) {
+		if (trackImage == null) {
+			context.getCompatDrawable(R.drawable.fastscroll_track)?.let { trackImage = it.wrap().mutate() }
+		}
+
+		trackImage?.let {
+			it.setCompatTint(color)
+			trackView.setImageDrawable(it)
+		}
+	}
+
+	/**
+	 * Set the color of the scroll handle.
+	 *
+	 * @param color The color for the scroll handle
+	 */
+	fun setHandleColor(@ColorInt color: Int) {
+		handleColor = color
+
+		if (handleImage == null) {
+			context.getCompatDrawable(R.drawable.fastscroll_handle)?.let { handleImage = it.wrap().mutate() }
+		}
+
+		handleImage?.let {
+			it.setCompatTint(handleColor)
+			handleView.setImageDrawable(it)
+		}
+	}
+
+	/**
+	 * Show the section bubble while scrolling.
+	 *
+	 * @param visible True to show the bubble, false to hide
+	 * @param always  True to always show the bubble, false to only show on handle touch
+	 */
+	@JvmOverloads
+	fun setBubbleVisible(visible: Boolean, always: Boolean = false) {
+		showBubble = visible
+		showBubbleAlways = visible && always
+	}
+
+	/**
+	 * Set the background color of the section bubble.
+	 *
+	 * @param color The background color for the section bubble
+	 */
+	fun setBubbleColor(@ColorInt color: Int) {
+		bubbleColor = color
+
+		if (bubbleImage == null) {
+			context.getCompatDrawable(bubbleSize.drawableId)?.let { bubbleImage = it.wrap().mutate() }
+		}
+
+		bubbleImage?.let {
+			it.setCompatTint(bubbleColor)
+			bubbleView.background = it
+		}
+	}
+
+	/**
+	 * Set the text color of the section bubble.
+	 *
+	 * @param color The text color for the section bubble
+	 */
+	fun setBubbleTextColor(@ColorInt color: Int) = bubbleView.setTextColor(color)
+
+	/**
+	 * Set the scaled pixel text size of the section bubble.
+	 *
+	 * @param size The scaled pixel text size for the section bubble
+	 */
+	fun setBubbleTextSize(size: Int) {
+		bubbleView.textSize = size.toFloat()
+	}
+
+	private fun getRecyclerViewTargetPosition(y: Float) = recyclerView?.let { recyclerView ->
+		val itemCount = recyclerView.adapter?.itemCount ?: 0
+
+		val proportion = when {
+			handleView.y == 0f -> 0f
+			handleView.y + handleHeight >= viewHeight - TRACK_SNAP_RANGE -> 1f
+			else -> y / viewHeight.toFloat()
+		}
+
+		var scrolledItemCount = (proportion * itemCount).roundToInt()
+
+		if (recyclerView.layoutManager.isLayoutReversed) {
+			scrolledItemCount = itemCount - scrolledItemCount
+		}
+
+		if (itemCount > 0) scrolledItemCount.coerceIn(0, itemCount - 1) else 0
+	} ?: 0
+
+	private fun setRecyclerViewPosition(y: Float) {
+		recyclerView?.layoutManager?.let { layoutManager ->
+			val targetPos = getRecyclerViewTargetPosition(y)
+			layoutManager.scrollToPosition(targetPos)
+			if (showBubble) sectionIndexer?.let { bubbleView.text = it.getSectionText(targetPos) }
+		}
+	}
+
+	private fun setViewPositions(y: Float) {
+		bubbleHeight = bubbleView.measuredHeight
+		handleHeight = handleView.measuredHeight
+
+		val bubbleHandleHeight = bubbleHeight + handleHeight / 2f
+
+		if (showBubble && viewHeight >= bubbleHandleHeight) {
+			bubbleView.y = (y - bubbleHeight).coerceIn(0f, viewHeight - bubbleHandleHeight)
+		}
+
+		if (viewHeight >= handleHeight) {
+			handleView.y = (y - handleHeight / 2).coerceIn(0f, viewHeight - handleHeight.toFloat())
+		}
+	}
+
+	private fun updateViewHeights() {
+		val measureSpec = MeasureSpec.makeMeasureSpec(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED)
+		bubbleView.measure(measureSpec, measureSpec)
+		bubbleHeight = bubbleView.measuredHeight
+		handleView.measure(measureSpec, measureSpec)
+		handleHeight = handleView.measuredHeight
+	}
+
+	private fun showBubble() {
+		if (!bubbleView.isVisible) {
+			bubbleView.isVisible = true
+			bubbleAnimator = bubbleView.animate().alpha(1f)
+				.setDuration(BUBBLE_ANIM_DURATION)
+				.setListener(alphaAnimatorListener)
+		}
+	}
+
+	private fun hideBubble() {
+		if (bubbleView.isVisible) {
+			bubbleAnimator = bubbleView.animate().alpha(0f)
+				.setDuration(BUBBLE_ANIM_DURATION)
+				.setListener(object : AnimatorListenerAdapter() {
+					override fun onAnimationEnd(animation: Animator) {
+						super.onAnimationEnd(animation)
+						bubbleView.isVisible = false
+						bubbleAnimator = null
+					}
+
+					override fun onAnimationCancel(animation: Animator) {
+						super.onAnimationCancel(animation)
+						bubbleView.isVisible = false
+						bubbleAnimator = null
+					}
+				})
+		}
+	}
+
+	private fun showScrollbar() {
+		if ((recyclerView?.computeVerticalScrollRange() ?: (0 - viewHeight)) > 0) {
+			scrollbar.translationX = scrollbarPaddingEnd
+			scrollbar.isVisible = true
+			scrollbarAnimator = scrollbar.animate().translationX(0f).alpha(1f)
+				.setDuration(SCROLLBAR_ANIM_DURATION)
+				.setListener(alphaAnimatorListener)
+		}
+	}
+
+	private fun hideScrollbar() {
+		scrollbarAnimator = scrollbar.animate().translationX(scrollbarPaddingEnd).alpha(0f)
+			.setDuration(SCROLLBAR_ANIM_DURATION)
+			.setListener(object : AnimatorListenerAdapter() {
+				override fun onAnimationEnd(animation: Animator) {
+					super.onAnimationEnd(animation)
+					scrollbar.isVisible = false
+					scrollbarAnimator = null
+				}
+
+				override fun onAnimationCancel(animation: Animator) {
+					super.onAnimationCancel(animation)
+					scrollbar.isVisible = false
+					scrollbarAnimator = null
+				}
+			})
+	}
+
+	private fun setHandleSelected(selected: Boolean) {
+		handleView.isSelected = selected
+		handleImage?.setCompatTint(if (selected) bubbleColor else handleColor)
+	}
+
+	private fun TypedArray.getSize(@StyleableRes index: Int, defValue: Int) = getInt(index, defValue).let { ordinal ->
+		Size.values().find { it.ordinal == ordinal } ?: Size.NORMAL
+	}
+
+	private fun Context.layout(attrs: AttributeSet? = null, size: Size = Size.NORMAL) {
+		inflate(this, R.layout.fast_scroller, this@FastScroller)
+
+		clipChildren = false
+		orientation = HORIZONTAL
+
+		@ColorInt var bubbleColor = Color.GRAY
+		@ColorInt var handleColor = Color.DKGRAY
+		@ColorInt var trackColor = Color.LTGRAY
+		@ColorInt var textColor = Color.WHITE
+
+		var showTrack = false
+		var textSize = size.textSize
+
+		withStyledAttributes(attrs, R.styleable.FastScroller) {
+			bubbleColor = getColor(R.styleable.FastScroller_bubbleColor, bubbleColor)
+			handleColor = getColor(R.styleable.FastScroller_handleColor, handleColor)
+			trackColor = getColor(R.styleable.FastScroller_trackColor, trackColor)
+			textColor = getColor(R.styleable.FastScroller_bubbleTextColor, textColor)
+			hideScrollbar = getBoolean(R.styleable.FastScroller_hideScrollbar, hideScrollbar)
+			showBubble = getBoolean(R.styleable.FastScroller_showBubble, showBubble)
+			showBubbleAlways = getBoolean(R.styleable.FastScroller_showBubbleAlways, showBubbleAlways)
+			showTrack = getBoolean(R.styleable.FastScroller_showTrack, showTrack)
+			bubbleSize = getSize(R.styleable.FastScroller_bubbleSize, size.ordinal)
+			textSize = getDimension(R.styleable.FastScroller_bubbleTextSize, bubbleSize.textSize)
+		}
+
+		setTrackColor(trackColor)
+		setHandleColor(handleColor)
+		setBubbleColor(bubbleColor)
+		setBubbleTextColor(textColor)
+		setHideScrollbar(hideScrollbar)
+		setBubbleVisible(showBubble, showBubbleAlways)
+		setTrackVisible(showTrack)
+
+		bubbleView.setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize)
+	}
+
+	interface FastScrollListener {
+
+		fun onFastScrollStart(fastScroller: FastScroller)
+
+		fun onFastScrollStop(fastScroller: FastScroller)
+	}
+
+	interface SectionIndexer {
+
+		fun getSectionText(position: Int): CharSequence
+	}
+}

app/src/main/java/org/koitharu/kotatsu/base/ui/widgets/KotatsuCoordinatorLayout.kt

@@ -7,14 +7,9 @@ import android.util.AttributeSet
 import android.view.View
 import androidx.coordinatorlayout.widget.CoordinatorLayout
 import androidx.core.view.doOnLayout
-import androidx.core.view.isVisible
 import androidx.customview.view.AbsSavedState
-import androidx.fragment.app.FragmentContainerView
-import androidx.viewpager.widget.ViewPager
 import com.google.android.material.appbar.AppBarLayout
-import com.google.android.material.tabs.TabLayout
 import org.koitharu.kotatsu.utils.ext.findChild
-import org.koitharu.kotatsu.utils.ext.findDescendant
 
 class KotatsuCoordinatorLayout @JvmOverloads constructor(
 	context: Context,

app/src/main/java/org/koitharu/kotatsu/details/ui/DetailsFragment.kt

@@ -229,7 +229,7 @@ class DetailsFragment :
 				return
 			}
 			imageViewCover.newImageRequest(scrobbling.coverUrl)
-				.crossfade(true)
+				.crossfade((300 * context?.animatorDurationScale!!).toInt())
 				.placeholder(R.drawable.ic_placeholder)
 				.fallback(R.drawable.ic_placeholder)
 				.error(R.drawable.ic_placeholder)
@@ -331,6 +331,7 @@ class DetailsFragment :
 		binding.root.updatePadding(
 			left = insets.left,
 			right = insets.right,
+			bottom = insets.bottom
 		)
 	}
 
@@ -357,7 +358,7 @@ class DetailsFragment :
 		val request = ImageRequest.Builder(context ?: return)
 			.target(binding.imageViewCover)
 			.data(imageUrl)
-			.crossfade(true)
+			.crossfade((300 * context?.animatorDurationScale!!).toInt())
 			.referer(manga.publicUrl)
 			.lifecycle(viewLifecycleOwner)
 		lastResult?.drawable?.let {

app/src/main/java/org/koitharu/kotatsu/details/ui/adapter/ChaptersAdapter.kt

@@ -3,12 +3,13 @@ package org.koitharu.kotatsu.details.ui.adapter
 import androidx.recyclerview.widget.DiffUtil
 import com.hannesdorfmann.adapterdelegates4.AsyncListDifferDelegationAdapter
 import org.koitharu.kotatsu.base.ui.list.OnListItemClickListener
+import org.koitharu.kotatsu.base.ui.widgets.FastScroller
 import org.koitharu.kotatsu.details.ui.model.ChapterListItem
 import kotlin.jvm.internal.Intrinsics
 
 class ChaptersAdapter(
 	onItemClickListener: OnListItemClickListener<ChapterListItem>,
-) :	AsyncListDifferDelegationAdapter<ChapterListItem>(DiffCallback()) {
+) :	AsyncListDifferDelegationAdapter<ChapterListItem>(DiffCallback()), FastScroller.SectionIndexer {
 
 	init {
 		setHasStableIds(true)
@@ -39,4 +40,8 @@ class ChaptersAdapter(
 			return null
 		}
 	}
+
+	override fun getSectionText(position: Int): CharSequence {
+		return items[position].chapter.number.toString()
+	}
 }

app/src/main/java/org/koitharu/kotatsu/details/ui/scrobbling/ScrobblingInfoBottomSheet.kt

@@ -27,6 +27,7 @@ import org.koitharu.kotatsu.image.ui.ImageActivity
 import org.koitharu.kotatsu.scrobbling.domain.model.ScrobblingInfo
 import org.koitharu.kotatsu.scrobbling.domain.model.ScrobblingStatus
 import org.koitharu.kotatsu.scrobbling.ui.selector.ScrobblingSelectorBottomSheet
+import org.koitharu.kotatsu.utils.ext.animatorDurationScale
 import org.koitharu.kotatsu.utils.ext.enqueueWith
 import org.koitharu.kotatsu.utils.ext.getDisplayMessage
 
@@ -110,7 +111,7 @@ class ScrobblingInfoBottomSheet :
 		ImageRequest.Builder(context ?: return)
 			.target(binding.imageViewCover)
 			.data(scrobbling.coverUrl)
-			.crossfade(true)
+			.crossfade((300 * context?.animatorDurationScale!!).toInt())
 			.lifecycle(viewLifecycleOwner)
 			.placeholder(R.drawable.ic_placeholder)
 			.fallback(R.drawable.ic_placeholder)

app/src/main/java/org/koitharu/kotatsu/tracker/ui/FeedFragment.kt

@@ -23,6 +23,7 @@ import org.koitharu.kotatsu.tracker.ui.adapter.FeedAdapter
 import org.koitharu.kotatsu.tracker.work.TrackWorker
 import org.koitharu.kotatsu.utils.ext.addMenuProvider
 import org.koitharu.kotatsu.utils.ext.getDisplayMessage
+import org.koitharu.kotatsu.utils.ext.getThemeColor
 
 class FeedFragment :
 	BaseFragment<FragmentFeedBinding>(),
@@ -56,7 +57,11 @@ class FeedFragment :
 			)
 			addItemDecoration(decoration)
 		}
-		binding.swipeRefreshLayout.isEnabled = false
+		with(binding.swipeRefreshLayout) {
+			setProgressBackgroundColorSchemeColor(context.getThemeColor(com.google.android.material.R.attr.colorPrimary))
+			setColorSchemeColors(context.getThemeColor(com.google.android.material.R.attr.colorOnPrimary))
+			isEnabled = false
+		}
 		addMenuProvider(FeedMenuProvider(binding.recyclerView, viewModel))
 
 		viewModel.content.observe(viewLifecycleOwner, this::onListChanged)

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

@@ -15,8 +15,10 @@ import android.view.ViewPropertyAnimator
 import android.view.Window
 import android.view.animation.Animation
 import androidx.activity.result.ActivityResultLauncher
+import androidx.annotation.DrawableRes
 import androidx.constraintlayout.motion.widget.MotionScene
 import androidx.core.app.ActivityOptionsCompat
+import androidx.core.content.ContextCompat
 import androidx.core.view.children
 import androidx.core.view.descendants
 import androidx.lifecycle.Lifecycle
@@ -122,6 +124,8 @@ fun Window.setNavigationBarTransparentCompat(context: Context, elevation: Float
 val Context.animatorDurationScale: Float
 	get() = Settings.Global.getFloat(this.contentResolver, Settings.Global.ANIMATOR_DURATION_SCALE, 1f)
 
+internal fun Context.getCompatDrawable(@DrawableRes drawableId: Int) = ContextCompat.getDrawable(this, drawableId)
+
 fun ViewPropertyAnimator.applySystemAnimatorScale(context: Context): ViewPropertyAnimator = apply {
 	this.duration = (this.duration * context.animatorDurationScale).toLong()
 }

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

@@ -13,7 +13,7 @@ import org.koitharu.kotatsu.utils.progress.ImageRequestIndicatorListener
 
 fun ImageView.newImageRequest(url: String?) = ImageRequest.Builder(context)
 	.data(url)
-	.crossfade(true)
+	.crossfade((300 * context.animatorDurationScale).toInt())
 	.target(this)
 
 fun ImageRequest.Builder.enqueueWith(loader: ImageLoader) = loader.enqueue(build())

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

@@ -0,0 +1,9 @@
+package org.koitharu.kotatsu.utils.ext
+
+import android.graphics.drawable.Drawable
+import androidx.annotation.ColorInt
+import androidx.core.graphics.drawable.DrawableCompat
+
+internal fun Drawable.setCompatTint(@ColorInt color: Int) = DrawableCompat.setTint(this, color)
+
+internal fun Drawable.wrap(): Drawable = DrawableCompat.wrap(this)

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

@@ -0,0 +1,19 @@
+package org.koitharu.kotatsu.utils.ext
+
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.StaggeredGridLayoutManager
+
+internal val RecyclerView.LayoutManager?.firstVisibleItemPosition
+	get() = when (this) {
+		is LinearLayoutManager -> findFirstVisibleItemPosition()
+		is StaggeredGridLayoutManager -> findFirstVisibleItemPositions(null)[0]
+		else -> 0
+	}
+
+internal val RecyclerView.LayoutManager?.isLayoutReversed
+	get() = when (this) {
+		is LinearLayoutManager -> reverseLayout
+		is StaggeredGridLayoutManager -> reverseLayout
+		else -> false
+	}

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

@@ -5,6 +5,7 @@ import android.graphics.Rect
 import android.view.View
 import android.view.ViewGroup
 import android.view.inputmethod.InputMethodManager
+import androidx.core.view.ViewCompat
 import androidx.core.view.children
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -145,3 +146,5 @@ fun RecyclerView.invalidateNestedItemDecorations() {
 		it.invalidateItemDecorations()
 	}
 }
+
+internal val View.compatPaddingStart get() = ViewCompat.getPaddingStart(this)

app/src/main/res/drawable/fastscroll_bubble.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:shape="rectangle">
+
+	<tools:solid android:color="#777777" />
+
+	<corners
+		android:topLeftRadius="@dimen/fastscroll_bubble_radius"
+		android:topRightRadius="@dimen/fastscroll_bubble_radius"
+		android:bottomLeftRadius="@dimen/fastscroll_bubble_radius"
+		android:bottomRightRadius="8dp" />
+
+	<size
+		android:height="@dimen/fastscroll_bubble_size"
+		android:width="@dimen/fastscroll_bubble_size" />
+
+	<padding
+		android:left="@dimen/fastscroll_bubble_padding"
+		android:right="@dimen/fastscroll_bubble_padding" />
+
+</shape>

app/src/main/res/drawable/fastscroll_bubble_small.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:shape="rectangle">
+
+	<tools:solid android:color="#777777" />
+
+	<corners
+		android:topLeftRadius="@dimen/fastscroll_bubble_radius_small"
+		android:topRightRadius="@dimen/fastscroll_bubble_radius_small"
+		android:bottomLeftRadius="@dimen/fastscroll_bubble_radius_small"
+		android:bottomRightRadius="8dp" />
+
+	<size
+		android:height="@dimen/fastscroll_bubble_size_small"
+		android:width="@dimen/fastscroll_bubble_size_small" />
+
+	<padding
+		android:left="@dimen/fastscroll_bubble_padding_small"
+		android:right="@dimen/fastscroll_bubble_padding_small" />
+
+</shape>

app/src/main/res/drawable/fastscroll_handle.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:shape="rectangle">
+
+	<tools:solid android:color="#555555" />
+
+	<corners android:radius="@dimen/fastscroll_handle_radius" />
+
+	<size
+		android:height="@dimen/fastscroll_handle_height"
+		android:width="@dimen/fastscroll_handle_width" />
+
+</shape>

app/src/main/res/drawable/fastscroll_track.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:shape="rectangle">
+
+	<tools:solid android:color="#CCCCCC" />
+
+	<size android:width="@dimen/fastscroll_track_width" />
+
+</shape>

app/src/main/res/layout-w720dp/fragment_chapters.xml

@@ -6,13 +6,13 @@
 	android:layout_width="match_parent"
 	android:layout_height="match_parent">
 
-	<androidx.recyclerview.widget.RecyclerView
+	<org.koitharu.kotatsu.base.ui.widgets.FastScrollRecyclerView
 		android:id="@+id/recyclerView_chapters"
 		android:layout_width="match_parent"
 		android:layout_height="match_parent"
 		android:clipToPadding="false"
 		android:orientation="vertical"
-		app:fastScrollEnabled="true"
+		app:handleColor="?attr/colorTertiary"
 		app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
 		tools:listitem="@layout/item_chapter" />
 

app/src/main/res/layout/fast_scroller.xml

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2022 Randy Webster. All rights reserved.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<merge
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools">
+
+	<TextView
+		android:id="@+id/fastscroll_bubble"
+		android:layout_width="wrap_content"
+		android:layout_height="wrap_content"
+		android:layout_gravity="end"
+		android:gravity="center"
+		android:maxLines="1"
+		android:visibility="gone"
+		tools:background="@drawable/fastscroll_bubble"
+		tools:text="A"
+		tools:textColor="#ffffff"
+		tools:visibility="visible" />
+
+	<FrameLayout
+		android:id="@+id/fastscroll_scrollbar"
+		android:layout_width="wrap_content"
+		android:layout_height="match_parent"
+		android:paddingEnd="@dimen/fastscroll_scrollbar_padding_end"
+		android:paddingStart="@dimen/fastscroll_scrollbar_padding_start"
+		android:visibility="gone"
+		tools:visibility="visible">
+
+		<ImageView
+			android:id="@+id/fastscroll_track"
+			android:layout_width="wrap_content"
+			android:layout_height="match_parent"
+			android:layout_gravity="center_horizontal"
+			tools:ignore="ContentDescription"
+			tools:src="@drawable/fastscroll_track" />
+
+		<ImageView
+			android:id="@+id/fastscroll_handle"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:layout_gravity="center_horizontal"
+			tools:ignore="ContentDescription"
+			tools:src="@drawable/fastscroll_handle" />
+
+	</FrameLayout>
+
+</merge>

app/src/main/res/layout/fragment_chapters.xml

@@ -17,7 +17,7 @@
 		tools:listitem="@layout/item_branch"
 		tools:visibility="visible" />
 
-	<androidx.recyclerview.widget.RecyclerView
+	<org.koitharu.kotatsu.base.ui.widgets.FastScrollRecyclerView
 		android:id="@+id/recyclerView_chapters"
 		android:layout_width="0dp"
 		android:layout_height="0dp"
@@ -28,8 +28,11 @@
 		android:layout_alignParentBottom="true"
 		android:clipToPadding="false"
 		android:orientation="vertical"
-		app:fastScrollEnabled="true"
+		app:bubbleColor="?attr/colorTertiary"
+		app:bubbleTextColor="?attr/colorOnTertiary"
+		app:handleColor="?attr/colorTertiary"
 		app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
+		app:showBubble="true"
 		tools:listitem="@layout/item_chapter" />
 
 	<com.google.android.material.progressindicator.CircularProgressIndicator

app/src/main/res/layout/fragment_feed.xml

@@ -7,7 +7,11 @@
 	android:layout_width="match_parent"
 	android:layout_height="match_parent">
 
-	<androidx.recyclerview.widget.RecyclerView
+	<FrameLayout
+		android:layout_width="match_parent"
+		android:layout_height="match_parent">
+
+		<org.koitharu.kotatsu.base.ui.widgets.FastScrollRecyclerView
 			android:id="@+id/recyclerView"
 			android:layout_width="match_parent"
 			android:layout_height="match_parent"
@@ -17,8 +21,10 @@
 			android:paddingTop="@dimen/grid_spacing_outer"
 			android:paddingRight="@dimen/list_spacing"
 			android:paddingBottom="@dimen/grid_spacing_outer"
-		app:fastScrollEnabled="true"
+			app:trackColor="?attr/colorOutline"
 			app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
 			tools:listitem="@layout/item_feed" />
 
+	</FrameLayout>
+
 </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

app/src/main/res/layout/fragment_library.xml

@@ -1,15 +1,24 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.recyclerview.widget.RecyclerView
+<FrameLayout
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
-	android:id="@+id/recyclerView"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:id="@+id/swipeRefreshLayout"
 	android:layout_width="match_parent"
 	android:layout_height="match_parent"
 	android:clipToPadding="false"
-	android:orientation="vertical"
 	android:paddingLeft="@dimen/list_spacing"
 	android:paddingTop="@dimen/grid_spacing_outer"
 	android:paddingRight="@dimen/list_spacing"
-	android:paddingBottom="@dimen/grid_spacing_outer"
+	android:paddingBottom="@dimen/grid_spacing_outer">
-	app:fastScrollEnabled="true"
+
-	app:layoutManager="org.koitharu.kotatsu.base.ui.list.FitHeightLinearLayoutManager" />
+	<org.koitharu.kotatsu.base.ui.widgets.FastScrollRecyclerView
+		android:id="@+id/recyclerView"
+		android:layout_width="match_parent"
+		android:layout_height="match_parent"
+		android:orientation="vertical"
+		app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
+		app:handleColor="?attr/colorTertiary"
+		tools:listitem="@layout/item_feed" />
+
+</FrameLayout>

app/src/main/res/layout/fragment_list.xml

@@ -7,6 +7,10 @@
 	android:layout_width="match_parent"
 	android:layout_height="match_parent">
 
+	<FrameLayout
+		android:layout_width="match_parent"
+		android:layout_height="match_parent">
+
 		<androidx.recyclerview.widget.RecyclerView
 			android:id="@+id/recyclerView"
 			android:layout_width="match_parent"
@@ -17,8 +21,10 @@
 			android:paddingRight="@dimen/list_spacing"
 			android:paddingTop="@dimen/grid_spacing_outer"
 			android:paddingBottom="@dimen/grid_spacing_outer"
-		app:fastScrollEnabled="true"
+			app:handleColor="?attr/colorTertiary"
 			tools:layoutManager="org.koitharu.kotatsu.base.ui.list.FitHeightLinearLayoutManager"
 			tools:listitem="@layout/item_manga_list" />
 
+	</FrameLayout>
+
 </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

app/src/main/res/layout/fragment_list_simple.xml

@@ -1,17 +1,24 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.recyclerview.widget.RecyclerView
+<FrameLayout
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	xmlns:tools="http://schemas.android.com/tools"
-	android:id="@+id/recyclerView"
+	android:id="@+id/swipeRefreshLayout"
 	android:layout_width="match_parent"
 	android:layout_height="match_parent"
 	android:clipToPadding="false"
-	android:orientation="vertical"
 	android:paddingLeft="@dimen/list_spacing"
 	android:paddingTop="@dimen/grid_spacing_outer"
 	android:paddingRight="@dimen/list_spacing"
-	android:paddingBottom="@dimen/grid_spacing_outer"
+	android:paddingBottom="@dimen/grid_spacing_outer">
-	app:fastScrollEnabled="true"
+
-	app:layoutManager="org.koitharu.kotatsu.base.ui.list.FitHeightLinearLayoutManager"
+	<org.koitharu.kotatsu.base.ui.widgets.FastScrollRecyclerView
-	tools:listitem="@layout/item_manga_list" />
+		android:id="@+id/recyclerView"
+		android:layout_width="match_parent"
+		android:layout_height="match_parent"
+		android:orientation="vertical"
+		app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
+		app:handleColor="?attr/colorTertiary"
+		tools:listitem="@layout/item_feed" />
+
+</FrameLayout>

app/src/main/res/layout/sheet_chapters.xml

@@ -22,13 +22,13 @@
 
 	</com.google.android.material.appbar.AppBarLayout>
 
-	<androidx.recyclerview.widget.RecyclerView
+	<org.koitharu.kotatsu.base.ui.widgets.FastScrollRecyclerView
 		android:id="@+id/recyclerView"
 		android:layout_width="match_parent"
 		android:layout_height="wrap_content"
 		android:clipToPadding="false"
 		android:orientation="vertical"
-		app:fastScrollEnabled="true"
+		app:handleColor="?attr/colorOutline"
 		app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
 		tools:listitem="@layout/item_chapter" />
 

app/src/main/res/values/attrs.xml

@@ -52,4 +52,20 @@
 		<attr name="progressStyle" format="reference" />
 	</declare-styleable>
 
+	<declare-styleable name="FastScroller">
+		<attr format="boolean" name="hideScrollbar" />
+		<attr format="boolean" name="showBubble" />
+		<attr format="boolean" name="showBubbleAlways" />
+		<attr format="boolean" name="showTrack" />
+		<attr format="color" name="bubbleColor" />
+		<attr format="color" name="bubbleTextColor" />
+		<attr format="color" name="handleColor" />
+		<attr format="color" name="trackColor" />
+		<attr format="dimension" name="bubbleTextSize" />
+		<attr format="enum" name="bubbleSize">
+			<enum name="normal" value="0" />
+			<enum name="small" value="1" />
+		</attr>
+	</declare-styleable>
+
 </resources>

app/src/main/res/values/dimens.xml

@@ -36,4 +36,27 @@
 	<dimen name="dialog_radius">8dp</dimen>
 
 	<dimen name="appwidget_corner_radius_inner">8dp</dimen>
+
+	<!-- FastScroller -->
+	<dimen name="fastscroll_bubble_radius">44dp</dimen>
+	<dimen name="fastscroll_bubble_size">88dp</dimen>
+	<dimen name="fastscroll_bubble_text_size">48sp</dimen>
+	<dimen name="fastscroll_bubble_padding">16dp</dimen>
+
+	<dimen name="fastscroll_bubble_radius_small">32dp</dimen>
+	<dimen name="fastscroll_bubble_size_small">64dp</dimen>
+	<dimen name="fastscroll_bubble_text_size_small">36sp</dimen>
+	<dimen name="fastscroll_bubble_padding_small">12dp</dimen>
+
+	<dimen name="fastscroll_handle_height">58dp</dimen>
+	<dimen name="fastscroll_handle_width">6dp</dimen>
+	<dimen name="fastscroll_handle_radius">4dp</dimen>
+
+	<dimen name="fastscroll_track_width">1dp</dimen>
+
+	<dimen name="fastscroll_scrollbar_margin_top">8dp</dimen>
+	<dimen name="fastscroll_scrollbar_margin_bottom">8dp</dimen>
+	<dimen name="fastscroll_scrollbar_padding_start">6dp</dimen>
+	<dimen name="fastscroll_scrollbar_padding_end">6dp</dimen>
+
 </resources>

app/src/main/res/values/ids.xml

@@ -3,4 +3,5 @@
     <item name="toolbar" type="id" />
     <item name="container" type="id" />
     <item name="action_leaks" type="id" />
+	<item name="fast_scroller" type="id" />
 </resources>