Create a Custom View using Canvas Template

import android.annotation.SuppressLint
import android.content.Context
import android.graphics.*
import android.util.AttributeSet
import android.view.View


class ShaderBackground : View {

   
    private lateinit var paint: Paint
    /** The screen half width.  */
    private var screenHalfWidth = 0f
    /** The screen half height.  */
    private var screenHalfHeight = 0f
    /** The screen width.  */
    private var screenWidth = 0f
    /** The screen height.  */
    private var screenHeight = 0f


    constructor(context: Context) : super(context) {
        init()
    }

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        init()
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(
        context,
        attrs,
        defStyleAttr
    ) {
        init()
    }

    private fun init() {
        paint = Paint();
        paint.strokeWidth = 10f;
        paint.style = Paint.Style.FILL_AND_STROKE;
        paint.isDither = true
    }


    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        screenWidth = MeasureSpec.getSize(widthMeasureSpec).toFloat()
        screenHeight = MeasureSpec.getSize(heightMeasureSpec).toFloat()
        screenHalfWidth = (screenWidth / 2)
        screenHalfHeight = (screenHeight / 2)
        setMeasuredDimension(screenWidth.toInt(), screenHeight.toInt())
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
    }

    @SuppressLint("DrawAllocation")
    override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)

        var gradient = RadialGradient(
            panelHalfWidth,
            topShaderCenterY,
            panelWidth,
            Color.BLUE, Color.BLACK,
            Shader.TileMode.CLAMP
        )
        paint.shader = gradient
        //LEFT TOP
        paint.color = Color.BLUE;
        canvas!!.drawRect(0f, 0f, 200, 100, paint)
        //LEFT BOTTOM
        paint.color = Color.BLUE;
        canvas.drawRect(0f, screenHeight-200, 100, screenHeight, paint)

        //RIGHT TOP
        paint.color = Color.RED;
        canvas!!.drawRect(screenwidth-200, 0f, screenWidth, screenHalfHeight, paint)
        //RIGHT BOTTOM
        paint.color = Color.GREEN;
        canvas.drawRect(screenwidth-200, screenHeight-200,screenwidth,screenHeight, paint)
    }

}

The result will be 4 rectangles on 4 sides of the view