AlertDialog With Custom Layout - Android Studio - Kotlin

In this example, we will add custom layout into alert dialog by clicking on a Button. See the following example:

activity_main.xml

Add the following code in the activity_main.xml file.

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:layout_margin="15dp"
    tools:context=".MainActivity">

        <Button
            android:id="@+id/btn_custom_alert_dialog"
            android:layout_marginTop="10dp"
            android:background="@color/colorAccent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textAllCaps="false"
            android:textColor="#000000"
            android:text="Custom Alert Dialog"/>

        <TextView
            android:id="@+id/txt_display_info"
            android:layout_marginTop="20dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="18dp"
            android:textColor="#000000"/>

</LinearLayout>
Create info_dialog.xml:  res-> layout-> info_dialog.xml
info_dialog.xml
Add the following code in the info_dialog.xml file.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp"
    android:orientation="vertical">

    <EditText
        android:id="@+id/edt_dia_first_name"
        android:hint="Enter First Name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:layout_margin="5dp"
        android:background="#E7E7E7"/>

    <EditText
        android:id="@+id/edt_dia_second_name"
        android:hint="Enter Second Name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:layout_margin="5dp"
        android:background="#E7E7E7"/>

    <EditText
        android:id="@+id/edt_dia_last_name"
        android:hint="Enter Last Name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:layout_margin="5dp"
        android:background="#E7E7E7"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:gravity="center">

        <Button
            android:id="@+id/btn_dia_submit"
            android:layout_margin="5dp"
            android:layout_weight="1"
            android:text="Submit"
            android:textAllCaps="false"
            android:background="@color/colorAccent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

        <Button
            android:id="@+id/btn_dia_cancel"
            android:layout_margin="5dp"
            android:layout_weight="1"
            android:textAllCaps="false"
            android:text="Cancel"
            android:background="@color/colorAccent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

    </LinearLayout>
</LinearLayout>

MainActivity.kt
Add the following code in the MainActivity.kt class.
package com.study.kotlinkatta

import android.os.Bundle
import android.view.LayoutInflater
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.info_dialog.view.*

class MainActivity : AppCompatActivity() {

    lateinit var btn_custom_alert_dialog: Button
    lateinit var txt_display_info: TextView

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

          txt_display_info = findViewById(R.id.txt_display_info)
          btn_custom_alert_dialog = findViewById(R.id.btn_custom_alert_dialog)
          btn_custom_alert_dialog.setOnClickListener {

              fun_custom_alert_dialog()
          }
        }

    private fun fun_custom_alert_dialog() {

        val alert_DialogView = LayoutInflater.from(this).inflate(R.layout.info_dialog, null)
        val mBuilder = AlertDialog.Builder(this)
            .setView(alert_DialogView)
            .setTitle("Info Dialog")
        val  alertDialog = mBuilder.show()
        var edt_dia_first_name: EditText
        var edt_dia_second_name: EditText
        var edt_dia_last_name: EditText
        var btn_dia_submit: Button
        var btn_dia_cancel: Button

        edt_dia_first_name = alert_DialogView.findViewById(R.id.edt_dia_first_name)
        edt_dia_second_name = alert_DialogView.findViewById(R.id.edt_dia_second_name)
        edt_dia_last_name = alert_DialogView.findViewById(R.id.edt_dia_last_name)

        btn_dia_submit = alert_DialogView.findViewById(R.id.btn_dia_submit)
        btn_dia_submit.setOnClickListener {
            val str_first_name = alert_DialogView.edt_dia_first_name.text.toString()
            val str_second_name = alert_DialogView.edt_dia_second_name.text.toString()
            val str_last_name = alert_DialogView.edt_dia_last_name.text.toString()

            if(str_first_name.equals("") || str_second_name.equals("") || str_last_name.equals("")){
                Toast.makeText(this,"Please enter details.",Toast.LENGTH_SHORT).show()
            }else {
                alertDialog.dismiss()
                txt_display_info.setText("Info:-" + "\nFirst Name:" + str_first_name + "\nSecond Name: " + str_second_name + "\nLast Name: " + str_last_name)
            }
        }

        btn_dia_cancel = alert_DialogView.findViewById(R.id.btn_dia_cancel)
        alert_DialogView.btn_dia_cancel.setOnClickListener {
            alertDialog.dismiss()
        }
    }
}
Output: