Android Custom Toolbar Back Button Example kotlin

Output:

1/  Modify the acitvity_main.xml file.

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
    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">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <com.google.android.material.appbar.MaterialToolbar
            android:id="@+id/customToolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:title="Custom Toolbar"
            app:navigationIcon="@drawable/baseline_arrow_back_ios_new_24"
            app:titleTextColor="@android:color/white" />
    </com.google.android.material.appbar.AppBarLayout>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="Custom Toolbar Example"
        android:textSize="18sp" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

2/  Modify the MainActivity.kt file.

package com.microappvalley.androidcustomtoolbarbackbuttonexamplekotlin

import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.google.android.material.appbar.MaterialToolbar

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

        val toolbar: MaterialToolbar = findViewById(R.id.customToolbar)
        setSupportActionBar(toolbar)

        supportActionBar?.setDisplayHomeAsUpEnabled(true)
        supportActionBar?.setDisplayShowHomeEnabled(true)

        toolbar.setNavigationOnClickListener {
            Toast.makeText(this@MainActivity, "Back button clicked", Toast.LENGTH_SHORT).show()
            finish()
        }
    }
}