Android Radio Buttons Using Kotlin With Example

Radio buttons allow the user to select one option at a time. A RadioButton as two states, selected and unselected.

Create a new Project in Kotlin

1. Open Android Studio.
2. Go to File => New => New Project. Write application name . Then, check Include Kotlin Support and click next button.
3. Select minimum SDK you need. However, we have selected 17 as minimum SDK. Then, click next button
4. Then, select Empty Activity => click next => click finish.
5. You will get a newly created project successfully if you have followed steps properly.

Use the below code to Implement a Radio Buttons with Kotlin

MainActivity.kt

activity_main.xml

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.*
import kotlinx.android.synthetic.main.activity_main.*
import android.widget.RadioGroup
import android.widget.Toast

class MainActivity : AppCompatActivity() {

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


//Radio button on click change

radio_group.setOnCheckedChangeListener(
    RadioGroup.OnCheckedChangeListener{
        group, checkedId ->

        val radio_langange: RadioButton = findViewById(checkedId)


        Toast.makeText(applicationContext," On Checked change :${radio_langange.text}",Toast.LENGTH_SHORT).show()


    }
)

        // Get radio group selected status and text using button click event
      button.setOnClickListener{
           // Get the checked radio button id from radio group
           var id: Int = radio_group.checkedRadioButtonId
          if (id!=-1){ // If any radio button checked from radio group
              // Get the instance of radio button using id
               val radio:RadioButton = findViewById(id)
            Toast.makeText(applicationContext,"On button click : ${radio.text}",
                 Toast.LENGTH_SHORT).show()
            }else{
                // If no radio button checked in this radio group
               Toast.makeText(applicationContext,"On button click : nothing selected",
                   Toast.LENGTH_SHORT).show()
          }
      }
   }

    // Get the selected radio button text using radio button on click listener
    fun radio_button_click(view: View){
      // Get the clicked radio button instance
      val radio: RadioButton = findViewById(radio_group.checkedRadioButtonId)
       Toast.makeText(applicationContext,"On click : ${radio.text}",
         Toast.LENGTH_SHORT).show()
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/root_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:padding="16dp"
>
    <RadioGroup
            android:layout_marginTop="30dp"
            android:id="@+id/radio_group"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#bccdd5"
            android:padding="15dp"
    >
        <TextView
                android:id="@+id/title"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Which is your favorite languages?"
                android:textStyle="bold"
                android:textSize="20sp"
        />
        <RadioButton
                android:id="@+id/tvenglish"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="English"
                android:onClick="radio_button_click"
        />
        <RadioButton
                android:id="@+id/tvspanish"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Spanish"
                android:onClick="radio_button_click"
        />
        <RadioButton
                android:id="@+id/tvfrench"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="French"
                android:onClick="radio_button_click"
        />
        <RadioButton
                android:id="@+id/tvmalayalam"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Malayalam"
                android:onClick="radio_button_click"
        />
    </RadioGroup>

    <Button

            android:id="@+id/button"
            android:layout_gravity="center"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="15dp"
            android:text="Get Selected Language"
    />
</LinearLayout>

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