Roll custom fast scroller

Drop the old IndicatorFastScroll library from Auxio and replace it with a hyper-specialized variant designed specifically for Auxio.
This not only eliminates a source of hacks/problems/bloat, it also removes a dependency on jcenter (Which is shutting down soon)

app/build.gradle

@@ -97,9 +97,6 @@ dependencies {
     // Material
     implementation 'com.google.android.material:material:1.3.0'
 
-    // Fast-Scroll
-    implementation 'com.reddit:indicator-fast-scroll:1.3.0'
-
     // Dialogs
     implementation 'com.afollestad.material-dialogs:core:3.3.0'
     implementation 'com.afollestad.material-dialogs:files:3.3.0'

app/src/main/java/org/oxycblt/auxio/songs/CobaltScrollThumb.kt

@@ -1,119 +0,0 @@
-package org.oxycblt.auxio.songs
-
-import android.content.Context
-import android.graphics.drawable.GradientDrawable
-import android.os.Build
-import android.util.AttributeSet
-import android.view.MotionEvent
-import android.view.View
-import android.view.ViewGroup
-import android.widget.TextView
-import androidx.constraintlayout.widget.ConstraintLayout
-import androidx.core.view.children
-import androidx.core.view.isVisible
-import androidx.core.widget.TextViewCompat
-import androidx.dynamicanimation.animation.DynamicAnimation
-import androidx.dynamicanimation.animation.SpringAnimation
-import androidx.dynamicanimation.animation.SpringForce
-import com.reddit.indicatorfastscroll.FastScrollItemIndicator
-import com.reddit.indicatorfastscroll.FastScrollerView
-import org.oxycblt.auxio.R
-import org.oxycblt.auxio.ui.Accent
-import org.oxycblt.auxio.ui.addIndicatorCallback
-import org.oxycblt.auxio.ui.inflater
-
-/**
- * A slimmed-down variant of [com.reddit.indicatorfastscroll.FastScrollerThumbView] designed
- * specifically for Auxio. Also fixes a memory leak that occurs from a bug fix they added.
- * @author OxygenCobalt
- */
-class CobaltScrollThumb @JvmOverloads constructor(
-    context: Context,
-    attrs: AttributeSet? = null,
-    defStyleAttr: Int = -1
-) : ConstraintLayout(context, attrs, defStyleAttr) {
-    private val thumbView: ViewGroup
-    private val textView: TextView
-    private val thumbAnim: SpringAnimation
-
-    init {
-        context.inflater.inflate(R.layout.fast_scroller_thumb_view, this, true)
-
-        val accent = Accent.get().getStateList(context)
-
-        thumbView = findViewById<ViewGroup>(R.id.fast_scroller_thumb).apply {
-            textView = findViewById(R.id.fast_scroller_thumb_text)
-
-            backgroundTintList = accent
-
-            // Workaround for API 21 tint bug
-            if (Build.VERSION.SDK_INT == Build.VERSION_CODES.LOLLIPOP) {
-                (background as GradientDrawable).apply {
-                    mutate()
-                    color = accent
-                }
-            }
-        }
-
-        textView.apply {
-            isVisible = true
-            TextViewCompat.setTextAppearance(this, R.style.TextAppearance_ThumbIndicator)
-        }
-
-        thumbAnim = SpringAnimation(thumbView, DynamicAnimation.TRANSLATION_Y).apply {
-            spring = SpringForce().also {
-                it.dampingRatio = SpringForce.DAMPING_RATIO_NO_BOUNCY
-            }
-        }
-
-        visibility = View.INVISIBLE
-        isActivated = false
-
-        post {
-            visibility = View.VISIBLE
-        }
-    }
-
-    /**
-     * Set up this view with a [FastScrollerView]. Should only be called once.
-     */
-    fun setup(scrollView: FastScrollerView) {
-        scrollView.addIndicatorCallback { indicator, centerY, _ ->
-            thumbAnim.animateToFinalPosition(centerY.toFloat() - (thumbView.measuredHeight / 2))
-
-            if (indicator is FastScrollItemIndicator.Text) {
-                textView.text = indicator.text
-            }
-        }
-
-        @Suppress("ClickableViewAccessibility")
-        scrollView.setOnTouchListener { _, event ->
-            scrollView.onTouchEvent(event)
-            scrollView.performClick()
-
-            val action = event.actionMasked
-            val actionValid = action != MotionEvent.ACTION_UP && action != MotionEvent.ACTION_CANCEL
-
-            isActivated = if (actionValid) {
-                isPointerOnItem(scrollView, event.y.toInt())
-            } else {
-                false
-            }
-
-            true
-        }
-    }
-
-    /**
-     * Hack that determines whether the pointer is currently on the [scrollView] or not.
-     */
-    private fun isPointerOnItem(scrollView: FastScrollerView, touchY: Int): Boolean {
-        scrollView.children.forEach { child ->
-            if (touchY in (child.top until child.bottom)) {
-                return true
-            }
-        }
-
-        return false
-    }
-}

app/src/main/java/org/oxycblt/auxio/songs/FastScrollThumb.kt

@@ -0,0 +1,81 @@
+package org.oxycblt.auxio.songs
+
+import android.content.Context
+import android.graphics.drawable.GradientDrawable
+import android.os.Build
+import android.util.AttributeSet
+import android.view.View
+import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.core.view.isVisible
+import androidx.core.widget.TextViewCompat
+import androidx.databinding.DataBindingUtil
+import androidx.dynamicanimation.animation.DynamicAnimation
+import androidx.dynamicanimation.animation.SpringAnimation
+import androidx.dynamicanimation.animation.SpringForce
+import org.oxycblt.auxio.R
+import org.oxycblt.auxio.databinding.ViewScrollThumbBinding
+import org.oxycblt.auxio.ui.Accent
+import org.oxycblt.auxio.ui.inflater
+
+/**
+ * The companion thumb for [FastScrollView]. This does not need any setup, instead pass it as an
+ * argument to [FastScrollView.setup].
+ * This code is fundamentally an adaptation of Reddit's IndicatorFastScroll, targeted towards
+ * Auxio specifically. Check them out here: https://github.com/reddit/IndicatorFastScroll/
+ * @author OxygenCobalt
+ */
+class FastScrollThumb @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null,
+    defStyleAttr: Int = -1
+) : ConstraintLayout(context, attrs, defStyleAttr) {
+    private val thumbAnim: SpringAnimation
+    private val binding = DataBindingUtil.inflate<ViewScrollThumbBinding>(
+        context.inflater, R.layout.view_scroll_thumb, this, true
+    )
+
+    init {
+        val accent = Accent.get().getStateList(context)
+
+        binding.thumbLayout.apply {
+            backgroundTintList = accent
+
+            // Workaround for API 21 tint bug
+            if (Build.VERSION.SDK_INT == Build.VERSION_CODES.LOLLIPOP) {
+                (background as GradientDrawable).apply {
+                    mutate()
+                    color = accent
+                }
+            }
+        }
+
+        binding.thumbText.apply {
+            isVisible = true
+            TextViewCompat.setTextAppearance(this, R.style.TextAppearance_ThumbIndicator)
+        }
+
+        thumbAnim = SpringAnimation(binding.thumbLayout, DynamicAnimation.TRANSLATION_Y).apply {
+            spring = SpringForce().also {
+                it.dampingRatio = SpringForce.DAMPING_RATIO_NO_BOUNCY
+            }
+        }
+
+        visibility = View.INVISIBLE
+        isActivated = false
+
+        post {
+            visibility = View.VISIBLE
+        }
+    }
+
+    /**
+     * Make the thumb jump to a new position and update its text to the given [indicator].
+     * This is not meant for use outside of the main [FastScrollView] code, don't use it.
+     */
+    fun jumpTo(indicator: FastScrollView.Indicator, centerY: Int) {
+        binding.thumbText.text = indicator.char.toString()
+        thumbAnim.animateToFinalPosition(
+            centerY.toFloat() - (binding.thumbLayout.measuredHeight / 2)
+        )
+    }
+}

app/src/main/java/org/oxycblt/auxio/songs/FastScrollView.kt

@@ -0,0 +1,217 @@
+package org.oxycblt.auxio.songs
+
+import android.content.Context
+import android.os.Build
+import android.util.AttributeSet
+import android.util.TypedValue
+import android.view.Gravity
+import android.view.HapticFeedbackConstants
+import android.view.MotionEvent
+import android.widget.LinearLayout
+import android.widget.TextView
+import androidx.appcompat.widget.AppCompatTextView
+import androidx.core.widget.TextViewCompat
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import org.oxycblt.auxio.R
+import org.oxycblt.auxio.logD
+import org.oxycblt.auxio.ui.Accent
+import org.oxycblt.auxio.ui.resolveAttr
+import org.oxycblt.auxio.ui.toColor
+import kotlin.math.ceil
+import kotlin.math.min
+
+/**
+ * A view that allows for quick scrolling through a [RecyclerView] with many items. Unlike other
+ * fast-scrollers, this one displays indicators instead of simply a scroll bar.
+ * This code is fundamentally an adaptation of Reddit's IndicatorFastScroll, targeted towards
+ * Auxio specifically. Check them out here: https://github.com/reddit/IndicatorFastScroll/
+ * @author OxygenCobalt
+ */
+class FastScrollView @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null,
+    defStyleAttr: Int = -1
+) : LinearLayout(context, attrs, defStyleAttr) {
+
+    // --- BASIC SETUP ---
+
+    private var mRecycler: RecyclerView? = null
+    private var mThumb: FastScrollThumb? = null
+    private var mGetItem: ((Int) -> Char)? = null
+
+    // --- INDICATORS ---
+
+    /** Representation of a single Indicator character in the view */
+    data class Indicator(val char: Char, val pos: Int)
+
+    private var indicators = listOf<Indicator>()
+
+    private val indicatorText: TextView
+    private val activeColor = Accent.get().color.toColor(context)
+    private val inactiveColor = android.R.attr.textColorSecondary.resolveAttr(context)
+
+    // --- STATE ---
+
+    private var hasPostedItemUpdate = false
+    private var lastPos = -1
+
+    init {
+        isFocusableInTouchMode = true
+        isClickable = true
+        gravity = Gravity.CENTER
+
+        val textPadding = TypedValue.applyDimension(
+            TypedValue.COMPLEX_UNIT_DIP, 4F, resources.displayMetrics
+        )
+
+        // Making this entire view a TextView will cause distortions due to the touch calculations
+        // using a height that is not wrapped to the text.
+        indicatorText = AppCompatTextView(context).apply {
+            gravity = Gravity.CENTER
+            includeFontPadding = false
+
+            TextViewCompat.setTextAppearance(this, R.style.TextAppearance_FastScroll)
+            setLineSpacing(textPadding, lineSpacingMultiplier)
+            setTextColor(inactiveColor)
+        }
+
+        addView(indicatorText)
+    }
+
+    /**
+     * Set up this view with a [RecyclerView] and a corresponding [FastScrollThumb].
+     */
+    fun setup(recycler: RecyclerView, thumb: FastScrollThumb, getItem: (Int) -> Char) {
+        check(mRecycler == null) { "Only set up this view once." }
+
+        mRecycler = recycler
+        mThumb = thumb
+        mGetItem = getItem
+
+        postIndicatorUpdate()
+    }
+
+    // --- INDICATOR UPDATES ---
+
+    private fun postIndicatorUpdate() {
+        if (!hasPostedItemUpdate) {
+            hasPostedItemUpdate = true
+
+            post {
+                val recycler = requireNotNull(mRecycler)
+
+                if (recycler.isAttachedToWindow && recycler.adapter != null) {
+                    updateIndicators()
+                }
+
+                hasPostedItemUpdate = false
+            }
+        }
+    }
+
+    private fun updateIndicators() {
+        val recycler = requireNotNull(mRecycler)
+        val getItem = requireNotNull(mGetItem)
+
+        indicators = 0.until(recycler.adapter!!.itemCount).mapNotNull { pos ->
+            Indicator(getItem(pos), pos)
+        }.distinctBy { it.char }
+
+        val textHeight = TypedValue.applyDimension(
+            TypedValue.COMPLEX_UNIT_SP, 14F, resources.displayMetrics
+        )
+
+        // If the scroller size is too small to contain all the entries, truncate entries
+        // so that the fast scroller entries fit.
+        val maxEntries = height / textHeight
+
+        if (indicators.size > maxEntries.toInt()) {
+            val truncateInterval = ceil(indicators.size / maxEntries).toInt()
+
+            check(truncateInterval > 1) {
+                "Needed to truncate, but truncateInterval was 1 or lower anyway"
+            }
+
+            logD("More entries than screen space, truncating by $truncateInterval.")
+
+            indicators = indicators.filterIndexed { index, _ ->
+                index % truncateInterval == 0
+            }
+        }
+
+        indicatorText.apply {
+            tag = indicators
+            text = indicators.joinToString("\n") { it.char.toString() }
+        }
+    }
+
+    // --- TOUCH ---
+
+    @Suppress("ClickableViewAccessibility")
+    override fun onTouchEvent(event: MotionEvent): Boolean {
+        performClick()
+
+        val success = handleTouch(event.action, event.y.toInt())
+
+        // Depending on the results, update the visibility of the thumb and the pressed state of
+        // this view.
+        isPressed = success
+        mThumb?.isActivated = success
+
+        return success
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private fun handleTouch(action: Int, touchY: Int): Boolean {
+        if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
+            indicatorText.setTextColor(inactiveColor)
+            lastPos = -1
+
+            return false
+        }
+
+        if (touchY in (indicatorText.top until indicatorText.bottom)) {
+            val textHeight = indicatorText.height / indicators.size
+            val indicatorIndex = min(
+                (touchY - indicatorText.top) / textHeight, indicators.lastIndex
+            )
+
+            val centerY = y.toInt() + (textHeight / 2) + (indicatorIndex * textHeight)
+
+            val touchedIndicator = indicators[indicatorIndex]
+
+            selectIndicator(touchedIndicator, centerY)
+
+            return true
+        }
+
+        return false
+    }
+
+    private fun selectIndicator(indicator: Indicator, indicatorCenterY: Int) {
+        if (indicator.pos != lastPos) {
+            lastPos = indicator.pos
+            indicatorText.setTextColor(activeColor)
+
+            // Stop any scroll momentum and snap-scroll to the position
+            mRecycler?.apply {
+                stopScroll()
+                (layoutManager as LinearLayoutManager).scrollToPositionWithOffset(
+                    indicator.pos, 0
+                )
+            }
+
+            mThumb?.jumpTo(indicator, indicatorCenterY)
+
+            performHapticFeedback(
+                if (Build.VERSION.SDK_INT >= 27) {
+                    // Dragging across a scroller is closer to moving a text handle
+                    HapticFeedbackConstants.TEXT_HANDLE_MOVE
+                } else {
+                    HapticFeedbackConstants.KEYBOARD_TAP
+                }
+            )
+        }
+    }
+}

app/src/main/java/org/oxycblt/auxio/songs/SongsFragment.kt

@@ -1,29 +1,21 @@
 package org.oxycblt.auxio.songs
 
-import android.os.Build
 import android.os.Bundle
-import android.util.TypedValue
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
 import androidx.recyclerview.widget.GridLayoutManager
-import androidx.recyclerview.widget.LinearLayoutManager
-import androidx.recyclerview.widget.RecyclerView
-import com.reddit.indicatorfastscroll.FastScrollItemIndicator
-import com.reddit.indicatorfastscroll.FastScrollerView
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentSongsBinding
 import org.oxycblt.auxio.logD
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.ui.Accent
-import org.oxycblt.auxio.ui.addIndicatorCallback
 import org.oxycblt.auxio.ui.canScroll
+import org.oxycblt.auxio.ui.fixAnimInfoLeak
 import org.oxycblt.auxio.ui.getSpans
 import org.oxycblt.auxio.ui.newMenu
-import kotlin.math.ceil
 
 /**
  * A [Fragment] that shows a list of all songs on the device.
@@ -73,75 +65,21 @@ class SongsFragment : Fragment() {
             }
         }
 
-        binding.songFastScroll.setup(binding.songRecycler, binding.songFastScrollThumb)
+        binding.songFastScroll.setup(binding.songRecycler, binding.songFastScrollThumb) { pos ->
+            val char = musicStore.songs[pos].name.first
+
+            if (char.isDigit()) '#' else char
+        }
 
         logD("Fragment created.")
 
         return binding.root
     }
 
-    /**
-     * Perform the (Frustratingly Long and Complicated) FastScrollerView setup.
-     * TODO: Roll FastScrollerView yourself and eliminate its dependency, you're already customizing it enough as it is.
-     */
-    private fun FastScrollerView.setup(recycler: RecyclerView, thumb: CobaltScrollThumb) {
-        var truncateInterval: Int = -1
-        val indicatorTextSize = TypedValue.applyDimension(
-            TypedValue.COMPLEX_UNIT_SP, 14F,
-            resources.displayMetrics
-        )
+    override fun onDestroyView() {
+        super.onDestroyView()
 
-        // API 22 and below don't support the state color, so just use the accent.
-        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.M) {
-            textColor = Accent.get().getStateList(requireContext())
-        }
-
-        setupWithRecyclerView(
-            recycler,
-            { pos ->
-                val char = musicStore.songs[pos].name.first
-
-                FastScrollItemIndicator.Text(
-                    // Use "#" if the character is a digit, also has the nice side-effect of
-                    // truncating extra numbers.
-                    if (char.isDigit()) "#" else char.toString()
-                )
-            },
-            null, false
-        )
-
-        showIndicator = { _, i, total ->
-            if (truncateInterval == -1) {
-                // If the scroller size is too small to contain all the entries, truncate entries
-                // so that the fast scroller entries fit.
-                val maxEntries = (height / (indicatorTextSize + textPadding))
-
-                if (total > maxEntries.toInt()) {
-                    truncateInterval = ceil(total / maxEntries).toInt()
-
-                    check(truncateInterval > 1) {
-                        "Needed to truncate, but truncateInterval was 1 or lower anyway"
-                    }
-
-                    logD("More entries than screen space, truncating by $truncateInterval.")
-                } else {
-                    truncateInterval = 1
-                }
-            }
-
-            // Any items that need to be truncated will be hidden
-            (i % truncateInterval) == 0
-        }
-
-        addIndicatorCallback { _, _, pos ->
-            recycler.apply {
-                (layoutManager as LinearLayoutManager).scrollToPositionWithOffset(pos, 0)
-
-                stopScroll()
-            }
-        }
-
-        thumb.setup(this)
+        fixAnimInfoLeak()
     }
 
     /**

app/src/main/java/org/oxycblt/auxio/ui/InterfaceUtils.kt

@@ -10,6 +10,7 @@ import android.graphics.drawable.AnimatedVectorDrawable
 import android.graphics.drawable.Drawable
 import android.os.Build
 import android.util.DisplayMetrics
+import android.util.TypedValue
 import android.view.LayoutInflater
 import android.view.View
 import android.view.WindowManager
@@ -23,8 +24,6 @@ import androidx.core.content.ContextCompat
 import androidx.fragment.app.Fragment
 import androidx.recyclerview.widget.RecyclerView
 import com.google.android.material.button.MaterialButton
-import com.reddit.indicatorfastscroll.FastScrollItemIndicator
-import com.reddit.indicatorfastscroll.FastScrollerView
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.logE
 import kotlin.reflect.KClass
@@ -129,6 +128,24 @@ fun Int.toDrawable(context: Context) = ContextCompat.getDrawable(context, this)
  */
 fun Int.toAnimDrawable(context: Context) = toDrawable(context) as AnimatedVectorDrawable
 
+/**
+ * Resolve this int into a color as if it was an attribute
+ */
+fun Int.resolveAttr(context: Context): Int {
+    // Convert the attribute into its color
+    val resolvedAttr = TypedValue()
+    context.theme.resolveAttribute(this, resolvedAttr, true)
+
+    // Then convert it to a proper color
+    val color = if (resolvedAttr.resourceId != 0) {
+        resolvedAttr.resourceId
+    } else {
+        resolvedAttr.data
+    }
+
+    return color.toColor(context)
+}
+
 /**
  * Create a [Toast] from a [String]
  * @param context [Context] required to create the toast
@@ -137,22 +154,6 @@ fun String.createToast(context: Context) {
     Toast.makeText(context.applicationContext, this, Toast.LENGTH_SHORT).show()
 }
 
-/**
- * Shortcut that allows me to add a indicator callback to [FastScrollerView] without
- * the nightmarish boilerplate that entails.
- */
-fun FastScrollerView.addIndicatorCallback(
-    callback: (indicator: FastScrollItemIndicator, centerY: Int, pos: Int) -> Unit
-) {
-    itemIndicatorSelectedCallbacks += object : FastScrollerView.ItemIndicatorSelectedCallback {
-        override fun onItemIndicatorSelected(
-            indicator: FastScrollItemIndicator,
-            indicatorCenterY: Int,
-            itemPosition: Int
-        ) = callback(indicator, indicatorCenterY, itemPosition)
-    }
-}
-
 // --- CONFIGURATION ---
 
 /**
@@ -253,8 +254,8 @@ private fun isSystemBarOnBottom(activity: Activity): Boolean {
 // --- HACKY NIGHTMARES ---
 
 /**
- * Use reflection to fix a memory leak in the [Fragment] source code where the focused view will
- * never be cleared. I can't believe I have to do this.
+ * Use ***REFLECTION*** to fix a memory leak in the [Fragment] source code where the focused view
+ * will never be cleared. I can't believe I have to do this.
  */
 fun Fragment.fixAnimInfoLeak() {
     try {

app/src/main/res/color/color_scroll_tints.xml

@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:color="?attr/colorPrimary" android:state_pressed="true" />
-    <item android:color="?android:attr/textColorSecondary" />
-</selector>

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

@@ -31,7 +31,7 @@
             app:layout_constraintTop_toBottomOf="@+id/song_toolbar"
             tools:listitem="@layout/item_song" />
 
-        <com.reddit.indicatorfastscroll.FastScrollerView
+        <org.oxycblt.auxio.songs.FastScrollView
             android:id="@+id/song_fast_scroll"
             android:layout_width="wrap_content"
             android:layout_height="0dp"
@@ -39,7 +39,7 @@
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintTop_toBottomOf="@+id/song_toolbar" />
 
-        <org.oxycblt.auxio.songs.CobaltScrollThumb
+        <org.oxycblt.auxio.songs.FastScrollThumb
             android:id="@+id/song_fast_scroll_thumb"
             android:layout_width="@dimen/width_thumb_view"
             android:layout_height="0dp"

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

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout>
+    <merge 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"
+        tools:layout_height="match_parent"
+        tools:layout_width="@dimen/fast_scroller_thumb_size"
+        tools:parentTag="androidx.constraintlayout.widget.ConstraintLayout">
+
+        <FrameLayout
+            android:id="@+id/thumb_layout"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:background="@drawable/thumb_circle"
+            android:elevation="@dimen/fast_scroller_thumb_elevation"
+            android:stateListAnimator="@animator/fast_scroll_thumb"
+            app:layout_constraintDimensionRatio="W,1:1"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent">
+
+            <TextView
+                android:id="@+id/thumb_text"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:gravity="center"
+                tools:text="A" />
+
+        </FrameLayout>
+    </merge>
+</layout>

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

@@ -16,7 +16,6 @@
         <item name="popupMenuStyle">@style/Widget.CustomPopup</item>
         <item name="colorControlNormal">@color/control_color</item>
         <item name="alertDialogTheme">@style/Theme.CustomDialog</item>
-        <item name="indicatorFastScrollerStyle">@style/FastScrollTheme</item>
         <item name="colorControlHighlight">@color/selection_color</item>
         <item name="colorControlActivated">?attr/colorPrimary</item>
         <item name="cornerRadius">0dp</item>
@@ -99,15 +98,10 @@
         <item name="android:fontFamily">@font/inter_exbold</item>
     </style>
 
-    <!-- Fast scroll theme -->
-    <style name="FastScrollTheme" parent="Widget.IndicatorFastScroll.FastScroller">
-        <item name="android:textAppearance">@style/TextAppearance.FastScroll</item>
-        <item name="android:textColor">@color/color_scroll_tints</item>
-    </style>
-
     <!-- Fast scroll text appearance -->
     <style name="TextAppearance.FastScroll" parent="TextAppearance.AppCompat.Body2">
         <item name="android:fontFamily">@font/inter_semibold</item>
+        <item name="android:lineSpacingExtra">@dimen/padding_tiny</item>
     </style>
 
     <!-- Fast scroll thumb appearance -->

build.gradle

@@ -5,8 +5,15 @@ buildscript {
 
     repositories {
         google()
-        jcenter() // TODO: Remove JCenter when Exoplayer migrates
         mavenCentral()
+
+        // TODO: Eliminate Exoplayer when it migrates to GMaven
+        jcenter {
+            content {
+                includeGroup("org.jetbrains.trove4j")
+                includeGroup("com.google.android.exoplayer")
+            }
+        }
     }
 
     dependencies {
@@ -22,8 +29,14 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
         mavenCentral()
+
+        jcenter {
+            content {
+                includeGroup("org.jetbrains.trove4j")
+                includeGroup("com.google.android.exoplayer")
+            }
+        }
     }
 }