Scrolling With a SeekBar

build.gradle

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.1.0-beta01'
    implementation 'androidx.core:core-ktx:1.2.0-alpha01'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta1'
    testImplementation 'junit:junit:4.13-beta-3'
    androidTestImplementation 'androidx.test:runner:1.2.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
}

layout.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <ScrollView
            android:id="@+id/scrollView"
            android:layout_width="0dp"
            android:layout_height="0dp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toTopOf="@id/seekBar"
            >

        <TextView
                android:id="@+id/scrollableTextView"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="PASTE A VERY LONG TEXT HERE"
                />

    </ScrollView>

    <SeekBar
            android:padding="32dp"
            android:id="@+id/seekBar"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toBottomOf="@id/scrollView"
            app:layout_constraintBottom_toBottomOf="parent"
            />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.kt

 override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        scrollView.viewTreeObserver.addOnGlobalLayoutListener {
            val scroll: Int = getScrollRange(scrollView)
            seekBar.min = 0
            seekBar.max = scroll

            seekBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
                override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
                    scrollView.scrollTo(0, progress)
                }

                override fun onStartTrackingTouch(seekBar: SeekBar) {
                }

                override fun onStopTrackingTouch(seekBar: SeekBar) {
                }
            })
        }
    }

    private fun getScrollRange(scrollView: ScrollView): Int {

        var scrollRange = 0
        if (scrollView.childCount > 0) {
            val child = scrollView.getChildAt(0)
            scrollRange =
                Math.max(0, child.height - (scrollView.height - scrollView.paddingBottom - scrollView.paddingTop))
        }

        return scrollRange
    }