How to use Radio button in Android?

This example demonstrates how do I use Radio button in android.
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/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=".MainActivity">
   <RadioGroup
      android:id="@+id/radioGender"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true">
   <RadioButton
      android:id="@+id/radioMale"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/radioMale"
      android:checked="true" />
   <RadioButton
      android:id="@+id/radioFemale"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/radioFemale" />
   </RadioGroup>
   <Button
      android:layout_below="@id/radioGender"
      android:id="@+id/btnDisplay"
      android:layout_centerInParent="true"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/btnDisplay" />
</RelativeLayout>
Step 3 − Add the following code to src/MainActivity.java
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
   RadioGroup radioGroup;
   RadioButton radioButton;
   Button button;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      addListenerButton();
   }
   private void addListenerButton() {
      radioGroup = findViewById(R.id.radioGender);
      button = findViewById(R.id.btnDisplay);
      button.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            int selectedID = radioGroup.getCheckedRadioButtonId();
            radioButton = findViewById(selectedID);
            Toast.makeText(MainActivity.this, radioButton.getText(),Toast.LENGTH_SHORT).show();
         }
      });
   }
}
Step 4 − Open res/values/strings.xml and add the following code
<resources>
   <string name="app_name">ample</string>
   <string name="radioMale">Male</string>
   <string name="radioFemale">Female</string>
   <string name="btnDisplay">Display</string>
</resources>
Step 5 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.sample">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −
Click here to download the project code.