This class is an extension to facilitate the use of AutoSizing on AppCompatTextView.

AutoSizingExt.kt

mport android.support.v4.widget.TextViewCompat
import android.support.v7.widget.AppCompatTextView
import android.util.TypedValue
import android.widget.TextView

/*
 * This class is an extension to facilitate the use of AutoSizing on AppCompatTextView.
 */

// Default

// Dimensions for uniform scaling are minTextSize = 12sp, maxTextSize = 112sp, and granularity = 1px.

fun AppCompatTextView.setAutoSizeTextTypeWithDefault(autoSizeTextType: Int) {
    TextViewCompat.setAutoSizeTextTypeWithDefaults(this, autoSizeTextType)
}

fun AppCompatTextView.setAutoSizeTextDefaultUniform() {
    TextViewCompat.setAutoSizeTextTypeWithDefaults(this, TextViewCompat.AUTO_SIZE_TEXT_TYPE_UNIFORM)
}

fun AppCompatTextView.setAutoSizeTextDefaultNone() {
    TextViewCompat.setAutoSizeTextTypeWithDefaults(this, TextViewCompat.AUTO_SIZE_TEXT_TYPE_NONE)
}

// Granularity

fun AppCompatTextView.setAutoSizeTextGranularity(autoSizeMinTextSize: Int, autoSizeMaxTextSize: Int, autoSizeStepGranularity: Int, unit: Int) {
    TextViewCompat.setAutoSizeTextTypeUniformWithConfiguration(this, autoSizeMinTextSize, autoSizeMaxTextSize, autoSizeStepGranularity, unit)
}

fun AppCompatTextView.setAutoSizeTextDefaultGranularity(autoSizeMinTextSize: Int, autoSizeMaxTextSize: Int) {
    val autoSizeStepGranularity = 2
    TextViewCompat.setAutoSizeTextTypeUniformWithConfiguration(this, autoSizeMinTextSize, autoSizeMaxTextSize, autoSizeStepGranularity, TypedValue.COMPLEX_UNIT_SP)
}

fun AppCompatTextView.setAutoSizeTextGranularitySp(autoSizeMinTextSize: Int, autoSizeMaxTextSize: Int, autoSizeStepGranularity: Int) {
    TextViewCompat.setAutoSizeTextTypeUniformWithConfiguration(this, autoSizeMinTextSize, autoSizeMaxTextSize, autoSizeStepGranularity, TypedValue.COMPLEX_UNIT_SP)
}

// Preset sizes

fun AppCompatTextView.setAutoSizeTextPresetSizes(autoSizeTextSizes: IntArray) {
    TextViewCompat.setAutoSizeTextTypeUniformWithPresetSizes(this, autoSizeTextSizes, TypedValue.COMPLEX_UNIT_SP)
}

fun AppCompatTextView.setAutoSizeTextPresetSizes(autoSizeTextSizes: IntArray, unit: Int) {
    TextViewCompat.setAutoSizeTextTypeUniformWithPresetSizes(this, autoSizeTextSizes, unit)
}

fun AppCompatTextView.setAutoSizeTextDefaultPresetSizes(textView: TextView) {
    val autoSizeTextSizes = intArrayOf(10, 12, 16, 20, 40, 100)
    TextViewCompat.setAutoSizeTextTypeUniformWithPresetSizes(textView, autoSizeTextSizes, TypedValue.COMPLEX_UNIT_SP)
}