RadioGroup Android Application

Introduction

In this article, we will learn how to use RadioGroup to manage multiple RadioButtons in an Android application. We will check one example to understand how it works in an android application.

What is a RadioGroup?

A RadioGroup is used to create a multiple-exclusion scope for a set of radio buttons. Checking one radio button that belongs to a radio group unchecks any previously checked radio button within the same group. Intially, all of the radio buttons are unchecked.

Pre-requisites

This article is for beginners who have just started developing android apps and want to know the basics. This post may not help you in real-world project development but, is a short working demonstration of RadioGroup and RadioButton control in Android.

RadioGroup in Android

I have developed a very simple example using RadioGroup, I have dragged two TextViews, five RadioButtons and a RadioGroup to my activity_my.xml. Furthermore, some backgroud colouring was added using layout editor in Android Studio.

In the code, setOnCheckedChangeListener listens to onCheckedChanged events on the RadioGroup. A very simple logic is added to identify which RadioButton was selected.

activity_my.xml

<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"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MyActivity"
    android:id="@+id/radio"
    android:background="#ffc5bdff">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Select your favoutire  movie Genre"
        android:id="@+id/textViewSelection"
        android:layout_above="@+id/radioButtonActionMovies"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginBottom="70dp" />
    <RadioGroup
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/radioGroup"
        android:layout_alignTop="@+id/textViewSelection"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="53dp">
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Action Movies"
            android:id="@+id/radioButtonActionMovies"
            android:layout_above="@+id/radioButtonAnimationMovies"
            android:layout_alignLeft="@+id/radioButtonAnimationMovies"
            android:layout_alignStart="@+id/radioButtonAnimationMovies"
            android:checked="false" />
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Animation Movies"
            android:id="@+id/radioButtonAnimationMovies"
            android:layout_centerVertical="true"
            android:layout_centerHorizontal="true"
            android:checked="false" />
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Horror Movies"
            android:id="@+id/radioButtonHorrorMovies"
            android:layout_below="@+id/radioButtonAnimationMovies"
            android:layout_alignLeft="@+id/radioButtonAnimationMovies"
            android:layout_alignStart="@+id/radioButtonAnimationMovies"
            android:checked="false" />
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Comedy Movies"
            android:id="@+id/radioButtonComedyMovies"
            android:layout_below="@+id/radioButtonHorrorMovies"
            android:layout_alignLeft="@+id/radioButtonHorrorMovies"
            android:layout_alignStart="@+id/radioButtonHorrorMovies"
            android:checked="false" />
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Sci-Fi Movies"
            android:id="@+id/radioButtonSciFiMovies"
            android:layout_below="@+id/radioButtonComedyMovies"
            android:layout_alignLeft="@+id/radioButtonComedyMovies"
            android:layout_alignStart="@+id/radioButtonComedyMovies"
            android:checked="false" />
    </RadioGroup>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="You Selected: "
        android:id="@+id/textViewChoice"
        android:layout_below="@+id/radioGroup"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:textStyle="bold"
        android:theme="@android:style/Animation.Toast" />
</RelativeLayout>

MyActivity.java

package app.radiobuttoncode.about.me.radiobutton;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.CompoundButton;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MyActivity extends ActionBarActivity {

    //declaring local variables
    public RadioGroup radioGroup;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

        //initializing variables
        radioGroup=(RadioGroup)findViewById(R.id.radioGroup);
       
        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener()
        {
                public void onCheckedChanged(RadioGroup group, int checkedId) {
                // checkedId is the RadioButton selected
                RadioButton rb=(RadioButton)findViewById(checkedId);
                textViewChoice.setText("You Selected "+rb.getText());
                //Toast.makeText(getApplicationContext(), rb.getText(), Toast.LENGTH_SHORT).show();
            }
        });
    }
}