Custom LinearLayout

SectionWithHeader.txt

This is how you set up a custom layout in kotlin, with a linearlayout and 3 textviews but these are embedded so a little
trick here to get the properties setters and getters needs to be done.  May not be the most efficient way but it works

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="DetailSectionHeaderText">
        <attr name="title" format="string" />
        <attr name="info" format="string" />
        <attr name="details" format="string" />
    </declare-styleable>

</resources>

row_detail_header_with_text.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <LinearLayout
        android:id="@+id/ll_activity_detail_section_header"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:background="@color/colorPrimary"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/tv_activity_detail_section_header_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Title"
            android:textColor="#ffffff" />

        <TextView
            android:id="@+id/tv_activity_detail_section_header_info"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Info: Awesome"
            android:textColor="#ffffff"/>

    </LinearLayout>

    <TextView
        android:id="@+id/tv_activity_detail_section_header_details"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginEnd="16dp"/>

</LinearLayout>

DetailSectionHeaderText.kt

import android.content.Context
import android.util.AttributeSet
import android.widget.LinearLayout
import com.matthewscorp.detail.R
import kotlinx.android.synthetic.main.row_detail_header_with_text.view.*

class DetailSectionHeaderText(context: Context?, attrs: AttributeSet?) : LinearLayout(context, attrs) {
    var title: String by Delegates.observable("") {
        _, _, new ->
        titleView.text = new
        invalidate()
    }

    var info: String by Delegates.observable("") {
        _, _, new ->
        infoView.text = new
        if (new == "") {
            infoView.visibility = View.GONE
            titleView.gravity = Gravity.CENTER_HORIZONTAL
        } else {
            infoView.visibility = View.VISIBLE
        }
        invalidate()
    }

    var detail: String by Delegates.observable("") {
        _, _, new ->
        detailView.text = new
        invalidate()
    }

    private lateinit var titleView: TextView
    private lateinit var infoView: TextView
    private lateinit var detailView: TextView

    init {
        context?.let {
            inflate(context, R.layout.row_detail_header_text, this)
            val titleView = tv_activity_detail_section_header_title
            val infoView = tv_activity_detail_section_header_info
            val detailView = tv_activity_detail_section_header_details

            val attributes = context.obtainStyledAttributes(attrs, R.styleable.DetailSectionHeaderText)
            title = attributes.getString(R.styleable.DetailSectionHeaderText_title)
            info = attributes.getString(R.styleable.DetailSectionHeaderText_info)
            detail = attributes.getString(R.styleable.DetailSectionHeaderText_details)
            attributes.recycle()
        }
    }
}

Because of the title, info and detail vars you are able to set these properties easily by calling in the activity code
using kotlinx the id name of the layout.  Say you insert the layout and use the id detailview_activity_details_section_one
then you would set the properties dynamically in your activity by calling:

detailview_activity_details_section_one.title = "Some Title"
detailview_activity_details_section_one.info = "Some Info"
detailview_activity_details_section_one.detail = "Some Long detail description"