Android Radio Button Example Using Kotlin

1. Creating New Project in Kotlin

• Open Android Studio.
• Go to File => New => New Project.Give Name To your application. Then, check Include Kotlin Support and click next button.
• Select minimum SDK you need. However, we have selected 21 as minimum SDK. Then, click next button.
• Then, select Empty Activity => click next => click finish.

2.Here We take Radio Group and inside Radio Group we take two Radio Button.We Provide Text to Radio Button Male and Female.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.dharmendra.radiobutton.MainActivity">


    <RadioGroup
        android:id="@+id/radioGroup"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="30dp"
        android:layout_marginTop="49dp"
        android:gravity="center">

        <RadioButton
            android:id="@+id/male"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Male" />

        <RadioButton
            android:id="@+id/female"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:text="Female" />

    </RadioGroup>


    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/radioGroup"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="56dp"
        android:text="Click" />

    <TextView
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignStart="@+id/radioGroup"
        android:layout_marginTop="22dp"
        android:text="Select Gender"
        android:textColor="@android:color/black"
        android:textStyle="bold" />

</RelativeLayout>

3.MainActivity.kt

package com.dharmendra.radiobutton

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.widget.Button
import android.widget.RadioButton
import android.widget.RadioGroup
import android.widget.Toast

class MainActivity : AppCompatActivity() {

    //To Store Selected Value
    private var selection = ""

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

        //FindViewByID for Radio Group and Button

        val radioGroup = findViewById<RadioButton>(R.id.radioGroup) as RadioGroup
        val btn=findViewById<Button>(R.id.button) as Button

        //On click For radioGroup

        radioGroup.setOnCheckedChangeListener { group, ID ->
            when (ID) {
                R.id.male -> {
                    
                    //If you Salected Male
                    selection = "Male"
                }
                R.id.female -> {
                    //If you Salected Female
                    selection = "Female"
                }
            }
        }

        //OnClick For Button

        btn.setOnClickListener {
            if(selection.isEmpty())
                Toast.makeText(this@MainActivity,"Please Select Any One",Toast.LENGTH_LONG).show()

            else
                Toast.makeText(this@MainActivity,"You have Selected "+selection,Toast.LENGTH_LONG).show()
        }
    }
}

Output