Android Radio Button Using Kotlin With Example

In this article, we will learn about android Radio Button using Kotlin. We will go through various example that demonstrates how to use different attributes of Radio Button.

In this article, we will get answer to questions like –

What is Radio Button?
Why should we consider Radio Button while designing ui for any app?
What are possibilities using Radio Button while designing ui? etc.

Let’s have a quick demo of things we want to cover in this tutorial –

Output

Tutorialwing Android Kotlin Radio Button Output

Getting Started

We can define android Radio Button widget as below –

An Android Radio Button is a two states button that can either be selected or unselected. There is no other option. Also, It can not be unselected, by clicking on it, once it is selected. That’s why we use this widget with radio group. When we use several radio buttons in a radio group, selecting one radio button make sure other radio buttons in the radio group are unselected.

Now, how do we use Radio Button in android application ?

Creating New Project

At first, we will create an application.
So, follow steps below to create any android project in Kotlin –

Step	Description
1.	Open Android Studio (Ignore if already done).
2.	Go to File => New => New Project. This will open a new window. Then, under Phone and Tablet section, select Empty Activity. Then, click Next.
3.	In next screen, select project name as RadioButton. Then, fill other required details.
4.	Then, clicking on Finish button creates new project.

Newbie in Android ?

Some very important concepts (Recommended to learn before you move ahead)

Install Android Studio

Create New Project in Android Studio

Android Project Structure

Run / Debug / Test Android App

Before we move ahead, we need to setup for viewBinding to access Android Radio Button Using Kotlin file without using findViewById() method.

Setup ViewBinding

Add viewBinding true in app/build.gradle file.

 
 android { 
 	// OTHER CODE... 
 	buildFeatures { 
 		viewBinding true 
 	} 
 }

Now, set content in activity using view binding.
Open MainActivity.kt file and write below code in it.

 
 class MainActivity : AppCompatActivity() { 
 	
 	private lateinit var binding: ActivityMainBinding 
 	
 	override fun onCreate(savedInstanceState: Bundle?) { 
 		super.onCreate(savedInstanceState) 
 		binding = ActivityMainBinding.inflate(layoutInflater) 
 		val view = binding.root 
 		setContentView(view) 
 	} 
 }

Now, we can access view in Kotlin file without using findViewById() method.

Using Radio Button in Kotlin

Follow steps below to use Radio Button in newly created project –

Open res/values/strings.xml folder. Then, add below code in it –

<resources>
    <string name="app_name">RadioButton</string>
    <string name="male">Male</string>
    <string name="female">Female</string>
</resources>

Open res/layout/activity_main.xml file. Then, add below code in it –

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <RadioGroup
        android:id="@+id/radioGroup"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingStart="20dp"
        android:paddingEnd="20dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent">

        <RadioButton
            android:id="@+id/radioMale"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="10dp"
            android:text="@string/male"/>

        <RadioButton
            android:id="@+id/radioFemale"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="10dp"
            android:text="@string/female"/>

    </RadioGroup>

</androidx.constraintlayout.widget.ConstraintLayout>

We can also access it in Kotlin File, MainActivity.kt, as below –

package com.tutorialwing.radiobutton

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import com.tutorialwing.radiobutton.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

	private lateinit var binding: ActivityMainBinding

	override fun onCreate(savedInstanceState: Bundle?) {
		super.onCreate(savedInstanceState)
		binding = ActivityMainBinding.inflate(layoutInflater)
		val view = binding.root
		setContentView(view)

		setOnCheckedChangeListener()
	}

	private fun setOnCheckedChangeListener() {
		binding.radioGroup.setOnCheckedChangeListener { group, checkedId ->
			val text = "You selected: " + if (R.id.radioMale == checkedId) "male" else "female"
			Toast.makeText(applicationContext, text, Toast.LENGTH_SHORT).show()
		}
	}
}

Now, run the application. We will get output as below –

Tutorialwing Android Kotlin Radio Button Output

Different Attributes of Radio Button in XML

Now, we will see how to use different attributes of Android Radio Button using Kotlin to customise it –

Set Id of Radio Button

Many a time, we need id of View to access it in kotlin file or create ui relative to that view in xml file. So, we can set id of Radio Button using android:id attribute like below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        />

Here, we have set id of Radio Button as radioButton_ID using android:id=”” attribute. So, if we need to reference this Radio Button, we need to use this id – radioButton_ID.
Learn to Set ID of Radio Button Dynamically

Set Width of Radio Button

We use android:layout_width=”” attribute to set width of Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        />

Width can be either “MATCH_PARENT” or “WRAP_CONTENT” or any fixed value (like 20dp, 30dp etc.).
Learn to Set Width of Radio Button Dynamically

Set Height of Radio Button

We use android:layout_height=”” attribute to set height of Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

Height can be either “MATCH_PARENT” or “WRAP_CONTENT” or any fixed value.
Learn to Set Height of Radio Button Dynamically

Set Padding of Radio Button

We use android:padding=”” attribute to set padding of Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        />

Here, we have set padding of 10dp in Radio Button using android:padding=”” attribute.
Learn to Set Padding of Radio Button Dynamically

Set Margin of Radio Button

We use android:layout_margin=”” attribute to set margin of Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        />

Here, we have set margin of 10dp in Radio Button using android:layout_margin=”” attribute.
Learn to Set Margin of Radio Button Dynamically

Set Background of Radio Button

We use android:background=”” attribute to set background of Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#ff0000"
        />

Here, we have set background of color #ff0000 in Radio Button using android:background=”” attribute.
Learn to Set Background of Radio Button Dynamically

Set Visibility of Radio Button

We use android:visibility=”” attribute to set visibility of Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        />

Here, we have set visibility of Radio Button using android:visiblity=”” attribute. Visibility can be of three types – gone, visible and invisible
Learn to Set Visibility of Radio Button Dynamically

Set Text of Radio Button

We use android:text=”” attribute to set text of Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        />

Here, we have set text (“Hello Tutorialwing”) in Radio Button using android:text=”” attribute.
Similarly, we can set any text using this attribute.
Learn to Set Text of Radio Button Dynamically

Set Color of Text in Radio Button

We use android:textColor=”” attribute to set color of text in Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textColor="#ffffff"     
        />

Here, we have set color (#ffffff i.e. white) of text (“Hello Tutorialwing”) in Radio Button using android:textColor=”” attribute. Similarly, we can set any color using this attribute.
Learn to Set Color of Radio Button Dynamically

Set Gravity of Radio Button

We use android:gravity=”” attribute to set gravity of text in Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:gravity="center_horizontal"
        />

Here, we have set gravity of text in Radio Button using android:gravity=”” attribute. Attribute value can be – “center_horizontal”, “center”, “center_vertical” etc.
Learn to Set Gravity of Radio Button Dynamically

Set Text in Uppercase, Lowercase

If we need to show text of Radio Button in uppercase or lowercase etc.

Set text in uppercase

We can use android:textAllCaps=”true” attribute to set text in uppercase. We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textAllCaps="true"
        />

Attribute android:textAllCaps=”true” sets text in uppercase. So, HELLO TUTORIALWING is set in Radio Button.

By default, false is set in this attribute. So, Whatever value is written in android:text=”” attribute, it will be set as it is. For example,

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textAllCaps="false"
        />

Above code will set Hello Tutorialwing to Radio Button.

How do we set text in lowercase?

Answer –

In xml file – write all the text in lowercase.

In kotlin file – take text as string. Then, convert it in lowercase. Then, set it to Radio Button.

Learn to Set Text in Uppercase or Lowercase Dynamically

Set Size of Text in Radio Button

We use android:textSize=”” attribute to set size of text in Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textSize="20sp"
        />

Here, we have set size of text in Radio Button using android:textSize=”” attribute.
Learn to Set Size of Text of Radio Button Dynamically

Set Style (Bold/italic) of Text in Radio Button

We use android:textStyle=”” attribute to set style (bold, italic etc.) of text in Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:textStyle="bold"
        />

Here, we have set style of text in Radio Button using android:textStyle=”” attribute. This attribute can take bold, italic or normal.
Learn to Set Style of Text of Radio Button Dynamically

Set Letter Spacing of Text in Radio Button

We use android:letterSpacing=”” attribute to set spacing between letters of text in Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:letterSpacing="1"
        />

Here, we have set spacing between letters of text in Radio Button using android:letterSpacing=”” attribute.
Learn to Set Letter Spacing of Text of Radio Button Dynamically

Set Typeface of Text in Radio Button

We use android:typeface=”” attribute to set typeface in Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:typeface="sans"
        />

Here, we have set typeface of text in Radio Button using android:typeface=”” attribute. This attribute can take values – “sans”, “normal”, “monospace” or “normal”.
Learn to Set Typeface of Radio Button Dynamically

Set fontFamily of Text in Radio Button

We use android:fontFamily=”” attribute to set fontFamily of text in Radio Button.
We can do it as below –

    <RadioButton
        android:id="@+id/radioButton_ID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Tutorialwing"
        android:fontFamily="sans-serif"
        />

Here, we have set fontFamily (Here, sans-serif) of text in Radio Button using android:fontFamily=”sans-serif” attribute.

Till now, we have see how to use android Radio Button using Kotlin. We have also gone through different attributes of Radio Button to perform certain task. Let’s have a look at list of such attributes and it’s related task.

Different Attributes of Android Radio Button Widget

Below are the various attributes that are used to customise android Radio Button Widget. However, you can check the complete list of attributes of Radio Button in it’s official documentation site. Here, we are going to list some of the important attributes of this widget –

Attributes of Radio Button widget are inherited from TextView, Compound Button and View. Some of the popular
attributes of Radio Button inherited from TextView are –

Sr.	XML Attributes	Description
1.	android:ems	Defines width of view in ems.
2.	android:gravity	It decides how text inside this view will be aligned. For example, center, left, right etc.
3.	android:height	Specifies height of the view.
4.	android:maxWidth	Specifies maximum allowed width of the view.
5.	android:minWidth	Specifies minimum allowed width of the view.
6.	android:width	Specifies width of the view.

Attributes of Radio Button inherited from Compound Button are –

Sr.	XML Attributes	Description
1.	android:button	Drawable for button graphic
2.	android:buttonTint	Specifies Tint to button graphic
3.	android:buttonTintMode	Blending mode used to apply the button graphic tint.

Attributes of Radio Button inherited from View are –

Sr.	XML Attributes	Description
1.	android:id	Specifies unique id of the view.
2.	android:padding	Specifies padding of view.
3.	android:onClick	Decides what to do when view is clicked.
4.	android:visibility	Decides whether to show or hide the view.
5.	android:tooltipText	Text to be shown when cursor id hovered on this view.
6.	android:background	Sets background to view.
7.	android:alpha	Sets alpha in view.

We have seen different attributes of Radio Button and how to use it. If you wish to visit post to learn more about it

Thus, we have seen what is Radio Button, how can we use android Radio Button using Kotlin ? etc. We also went through different attributes of android Radio Button.