android kotlin - Create GradientDrawable Programmatically

MainActivity.kt

package com.example.jetpack

import android.graphics.Color
import android.graphics.drawable.GradientDrawable
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {

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

        // set image view drawable liner gradient
        imageView.setImageDrawable(linearGradientDrawable())

        // set image view drawable radial gradient
        imageView2.setImageDrawable(radialGradientDrawable())

        // set image view drawable sweep gradient
        imageView3.setImageDrawable(sweepGradientDrawable())
    }
}


// method to generate linear gradient drawable
private fun linearGradientDrawable():GradientDrawable{
    return GradientDrawable().apply {
        colors = intArrayOf(
            Color.parseColor("#008000"),
            Color.parseColor("#8DB600"),
            Color.parseColor("#D0FF14")
        )
        gradientType = GradientDrawable.LINEAR_GRADIENT
        shape = GradientDrawable.RECTANGLE
        orientation = GradientDrawable.Orientation.BOTTOM_TOP

        // border around drawable
        setStroke(5,Color.parseColor("#4B5320"))
    }
}


// method to generate radial gradient drawable
private fun radialGradientDrawable():GradientDrawable{
    return GradientDrawable().apply {
        colors = intArrayOf(
            Color.parseColor("#DA1884"),
            Color.parseColor("#FFF600"),
            Color.parseColor("#800020")
        )
        gradientType = GradientDrawable.RADIAL_GRADIENT
        shape = GradientDrawable.RECTANGLE

        gradientRadius = 350F

        // border around drawable
        setStroke(5,Color.parseColor("#CD5700"))
    }
}


// method to generate sweep gradient drawable
private fun sweepGradientDrawable():GradientDrawable{
    return GradientDrawable().apply {
        colors = intArrayOf(
            Color.parseColor("#00BFFF"),
            Color.parseColor("#00CC99"),
            Color.parseColor("#D70040"),
            Color.parseColor("#F7E7CE"),
            Color.parseColor("#DFFF00")
        )
        gradientType = GradientDrawable.SWEEP_GRADIENT
        shape = GradientDrawable.RECTANGLE

        // border around drawable
        setStroke(5,Color.parseColor("#232B2B"))
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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/constraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="0dp"
        android:layout_height="150dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:srcCompat="@tools:sample/avatars" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Linear Gradient"
        app:layout_constraintEnd_toEndOf="@+id/imageView"
        app:layout_constraintStart_toStartOf="@+id/imageView"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="0dp"
        android:layout_height="150dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="24dp"
        android:layout_marginEnd="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView"
        tools:srcCompat="@tools:sample/avatars" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Radial Gradient"
        app:layout_constraintEnd_toEndOf="@+id/imageView2"
        app:layout_constraintStart_toStartOf="@+id/imageView2"
        app:layout_constraintTop_toBottomOf="@+id/imageView2" />

    <ImageView
        android:id="@+id/imageView3"
        android:layout_width="0dp"
        android:layout_height="150dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="24dp"
        android:layout_marginEnd="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2"
        tools:srcCompat="@tools:sample/avatars" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Sweep Gradient"
        app:layout_constraintEnd_toEndOf="@+id/imageView3"
        app:layout_constraintStart_toStartOf="@+id/imageView3"
        app:layout_constraintTop_toBottomOf="@+id/imageView3" />

</androidx.constraintlayout.widget.ConstraintLayout>