Android studio Toolbar using kotlin

        Mainactivity Xml 

<?xml version="1.0" encoding="utf-8"?>
       <android.support.constraint.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/appbar_layout_activity"        android:layout_width="match_parent"        android:layout_height="match_parent"        tools:context="com.andelachatbot.smithnwokocha.myapplication.MainActivity">

           <android.support.v7.widget.Toolbar               android:id="@+id/toolbar"               android:layout_width="0dp"               android:layout_height="200dp"               android:background="@drawable/andelaalc"               android:minHeight="?attr/actionBarSize"               android:theme="?attr/actionBarTheme"               app:layout_constraintEnd_toEndOf="parent"               app:layout_constraintStart_toStartOf="parent"
               app:layout_constraintTop_toTopOf="parent" />
    <TextView        android:id="@+id/textView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginEnd="174dp"        android:layout_marginStart="152dp"        android:layout_marginTop="19dp"        android:text="About Andela Learning Community"        android:textAlignment="center"        android:textColor="@android:color/black"        android:textSize="18sp"        android:textStyle="bold"        app:layout_constraintEnd_toEndOf="parent"        app:layout_constraintStart_toStartOf="parent"        app:layout_constraintTop_toBottomOf="@+id/toolbar" />
    <View        android:id="@+id/view"        android:layout_width="match_parent"        android:layout_height="5dp"        android:layout_marginTop="1dp"        android:background="@color/colorPrimary"        app:layout_constraintLeft_toLeftOf="parent"        app:layout_constraintRight_toRightOf="parent"        app:layout_constraintTop_toBottomOf="@+id/textView" />
    <View        android:layout_width="match_parent"        android:layout_height="5dp"        android:layout_marginTop="19dp"        android:background="@color/colorPrimary"        app:layout_constraintLeft_toLeftOf="parent"        app:layout_constraintRight_toRightOf="parent"        app:layout_constraintTop_toBottomOf="@+id/toolbar" />
    <TextView        android:id="@+id/textView2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginBottom="35dp"        android:text="@string/tech"        android:textAlignment="center"        android:textColor="@android:color/black"        android:textSize="18sp"        app:layout_constraintBottom_toTopOf="@+id/button"        app:layout_constraintHorizontal_bias="0.0"        app:layout_constraintLeft_toLeftOf="parent"        app:layout_constraintRight_toRightOf="parent" />
    <Button        android:id="@+id/button"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginBottom="4dp"
        android:background="@android:color/holo_orange_dark"        android:text="Chat Bot"        app:layout_constraintBottom_toBottomOf="parent"        app:layout_constraintLeft_toLeftOf="parent"        app:layout_constraintRight_toRightOf="parent" />
</android.support.constraint.ConstraintLayout>

Kotlin Code

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val toolbar = findViewById<Toolbar>(R.id.toolbar)
        setSupportActionBar(toolbar)
        if (supportActionBar != null) {
            supportActionBar?.setDisplayHomeAsUpEnabled(true)
            supportActionBar?.setDisplayShowTitleEnabled(false)
            supportActionBar?.setDisplayShowHomeEnabled(false)
        }