activity_main.xml

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

    <com.hamurcuabi.myapplication.CustomToolbarView
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:ctv_showEndIcon="true"
        app:ctv_textStyle="Bold"
        app:ctv_title="Xml test" />

    <Button
        android:id="@+id/btn1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginHorizontal="12dp"
        android:layout_marginTop="100dp"
        android:layout_marginBottom="12dp"
        android:text="Type 1"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="12dp"
        android:text="Type 2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="12dp"
        android:text="Type 3"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</LinearLayout>

attrs.xml

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

    <declare-styleable name="CustomToolbarView">
        <attr name="ctv_textStyle" format="enum">
            <enum name="Normal" value="0" />
            <enum name="Bold" value="1" />
        </attr>
        <attr name="ctv_title" format="string" />
        <attr name="ctv_showEndIcon" format="boolean" />
    </declare-styleable>

</resources>

CustomToolbarView.kt

package com.hamurcuabi.myapplication

import android.content.Context
import android.graphics.Typeface
import android.util.AttributeSet
import android.view.LayoutInflater
import android.view.View
import android.widget.FrameLayout
import androidx.core.view.isVisible
import com.hamurcuabi.myapplication.databinding.ViewCustomToolbarBinding

class CustomToolbarView @JvmOverloads constructor(
    context: Context,
    attributeSet: AttributeSet? = null,
    defStyle: Int = 0
) : FrameLayout(context, attributeSet, defStyle) {

    private val binding = ViewCustomToolbarBinding
        .inflate(LayoutInflater.from(context), this, true)

    init {
        binding.root.id=View.generateViewId()
        context.obtainStyledAttributes(attributeSet, R.styleable.CustomToolbarView).apply {
            val title: String? = getString(R.styleable.CustomToolbarView_ctv_title)
            val showEndIcon = getBoolean(R.styleable.CustomToolbarView_ctv_showEndIcon, false)
            val textStyle = getInt(R.styleable.CustomToolbarView_ctv_textStyle, CustomToolbarViewTextStyle.Normal.type)

            recycle()
            updateTitle(title)
            showEndIcon(showEndIcon)
            updateTitleStyle(textStyle)
        }
    }

    private fun updateTitleStyle(type: Int) {
        val style = when (CustomToolbarViewTextStyle.fromValue(type)) {
            CustomToolbarViewTextStyle.Normal -> {
                Typeface.NORMAL
            }
            CustomToolbarViewTextStyle.Bold -> {
                Typeface.BOLD
            }
        }
        binding.tvTitle.setTypeface(null, style)
    }

    fun updateTitleStyle(style: CustomToolbarViewTextStyle) {
        updateTitleStyle(style.type)
    }

    fun updateTitle(title: String?) {
        binding.tvTitle.text = title
    }

    fun showEndIcon(isVisible: Boolean) {
        binding.imgEnd.isVisible = isVisible
    }

}

enum class CustomToolbarViewTextStyle(val type: Int) {
    Normal(0),
    Bold(1);

    companion object {

        fun fromValue(type: Int): CustomToolbarViewTextStyle {
            return values().firstOrNull { it.type == type } ?: Normal
        }
    }

}

view_custom_toolbar.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"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/imgStart"
        android:layout_width="36dp"
        android:layout_height="36dp"
        android:padding="8dp"
        android:src="@drawable/ic_arrow"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="dsadsa"
        android:textColor="@color/black"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="@id/imgStart"
        app:layout_constraintEnd_toStartOf="@id/imgEnd"
        app:layout_constraintStart_toEndOf="@id/imgStart"
        app:layout_constraintTop_toTopOf="@id/imgStart" />

    <ImageView
        android:id="@+id/imgEnd"
        android:layout_width="36dp"
        android:layout_height="36dp"
        android:padding="8dp"
        android:src="@drawable/ic_add"
        app:layout_constraintBottom_toBottomOf="@id/imgStart"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="@id/imgStart" />

</androidx.constraintlayout.widget.ConstraintLayout>