RadioButton is a widget used in android which provides functionality to choose a single option from multiple sets of options. This is generally used when we want the user to select only one option from the set of given options. In this article, we will take a look at How to use Radio Buttons on Android.
Note: This Android article covers in both Java and Kotlin languages.
Step by Step Implementation
Step 1: Create a New Project in Android Studio
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio.
Step 2: Working with the activity_main.xml file
Navigate to app > res > layout > activity_main.xml and add the below code to it. Comments are added in the code to get to know in detail.
XML
<?xml version="1.0" encoding="utf-8"?><RelativeLayout android:id="@+id/idRLContainer" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".MainActivity"> <!--on below line we are creating a text for our app--> <TextView android:id="@+id/idTVHeading" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_above="@id/idTVStatus" android:layout_centerInParent="true" android:layout_margin="20dp" android:gravity="center" android:padding="10dp" android:text="Radio Button in Android" android:textAlignment="center" android:textColor="@color/black" android:textSize="20sp" android:textStyle="bold" /> <!--on below line we are creating a text view--> <TextView android:id="@+id/idTVStatus" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_above="@id/idRadioGroup" android:layout_centerInParent="true" android:layout_margin="20dp" android:gravity="center" android:padding="10dp" android:text="Status" android:textAlignment="center" android:textColor="@color/black" android:textSize="20sp" android:textStyle="bold" /> <!--on below line we are creating a radio group--> <RadioGroup android:id="@+id/idRadioGroup" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:gravity="center"> <!--on below line we are creating a radio buttons--> <RadioButton android:id="@+id/idBtnJavaRadio" android:layout_width="150dp" android:layout_height="wrap_content" android:padding="4dp" android:text="Java" android:textAlignment="center" android:textColor="@color/black" android:textSize="20sp" /> <RadioButton android:id="@+id/idBtnKotlinRadio" android:layout_width="150dp" android:layout_height="wrap_content" android:padding="4dp" android:text="Kotlin" android:textAlignment="center" android:textColor="@color/black" android:textSize="20sp" /> <RadioButton android:id="@+id/idBtnFlutterRadio" android:layout_width="150dp" android:layout_height="wrap_content" android:padding="4dp" android:text="Flutter" android:textAlignment="center" android:textColor="@color/black" android:textSize="20sp" /> </RadioGroup> </RelativeLayout> |
Step 3: Working with the MainActivity file
Navigate to app > java > your app’s package name > MainActivity file and add the code below. Comments are added in the code to get to know in detail.
Kotlin
package com.gtappdevelopers.kotlingfgproject import android.os.Bundleimport android.widget.RadioButtonimport android.widget.RadioGroupimport android.widget.TextViewimport androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() { // on below line we are creating a variable. lateinit var radioGrp: RadioGroup lateinit var statusTV: TextView override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) // on below line we are initializing our variables. radioGrp = findViewById(R.id.idRadioGroup) statusTV = findViewById(R.id.idTVStatus) radioGrp.setOnCheckedChangeListener { group, checkedId -> // Get the selected Radio Button val radioButton = group .findViewById(checkedId) as RadioButton // on below line we are setting // text for our status text view. statusTV.text = radioButton.text } }} |
Java
package com.gtappdevelopers.kotlingfgproject; import android.os.Bundle;import android.widget.RadioButton;import android.widget.RadioGroup;import android.widget.TextView;import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { // on below line we are creating a variable. private RadioGroup radioGrp; private TextView statusTV; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // on below line we are initializing our variables. radioGrp = findViewById(R.id.idRadioGroup); statusTV = findViewById(R.id.idTVStatus); radioGrp.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { @Override public void onCheckedChanged(RadioGroup group, int checkedId) { // Get the selected Radio Button RadioButton radioButton = group.findViewById(checkedId); // on below line we are setting text // for our status text view. statusTV.setText(radioButton.getText()); } }); }} |
Now run your application to see the output of it.
Output:
