Android RadioGroup & RadioButton Tutorial

1- RadioButton & RadioGroup

RadioButton is a view in Android which is usually used with RadioGroup. In which, RadioGroup is container which contains RadioButtons, when you check and chose a radio button in group, all other radio button in group will be deselected.

Here are image that RadioButton grouped in different groups..
RadioGroup can arrange  RadioButton horizontally or vertically.

2- RadioGroup & RadioButtons example

Create a project named AndroidRadioDemo.
  • Application interface design (See SLIDE):

The application interface:
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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="org.o7planning.androidradiodemo.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Game Settings"
        android:id="@+id/textView"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Game character"
        android:id="@+id/textView2"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="39dp" />

    <RadioGroup
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:layout_below="@+id/textView2"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="38dp"
        android:id="@+id/radioGroup_character">

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Male"
            android:id="@+id/radioButton_male"
            android:checked="true" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Female"
            android:id="@+id/radioButton_female"
            android:checked="false" />
    </RadioGroup>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Difficulty Level"
        android:id="@+id/textView3"
        android:layout_below="@+id/radioGroup_character"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <RadioGroup
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_below="@+id/textView3"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="15dp"
        android:orientation="horizontal"
        android:id="@+id/radioGroup_diffLevel">

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Easy"
            android:id="@+id/radioButton_easy"
            android:checked="false" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Medium"
            android:id="@+id/radioButton_medium"
            android:checked="true" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hard"
            android:id="@+id/radioButton_hard"
            android:checked="false" />
    </RadioGroup>

    <Button
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Save"
        android:id="@+id/button_save"
        android:layout_below="@+id/radioGroup_diffLevel"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="41dp" />

</RelativeLayout>
MainActivity.java
package org.o7planning.androidradiodemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

   private RadioGroup radioGroupCharacter;
   private RadioButton radioButtonMale;
   private RadioButton radioButtonFemale;

   private RadioGroup radioGroupDiffLevel;

   private Button buttonSave;


   private String LOGTAG = "AndroidRadioDemo";



   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);

       //
       this.radioGroupCharacter= (RadioGroup) this.findViewById(R.id.radioGroup_character);
       this.radioButtonMale = (RadioButton) this.findViewById(R.id.radioButton_male);
       this.radioButtonFemale  =  (RadioButton)this.findViewById(R.id.radioButton_female);

       this.radioGroupDiffLevel= (RadioGroup) this.findViewById(R.id.radioGroup_diffLevel);

       this.buttonSave= (Button) this.findViewById(R.id.button_save);

       // When radio group "Difficulty Level" checked change.
       this.radioGroupDiffLevel.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
           @Override
           public void onCheckedChanged(RadioGroup group, int checkedId) {
                doOnDifficultyLevelChanged(group, checkedId);
           }
       });

       // When radio button "Female" checked change.
       this.radioButtonMale.setOnCheckedChangeListener(new RadioButton.OnCheckedChangeListener() {

           @Override
           public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
               doOnGameCharacterChanged(buttonView,isChecked);
           }
       });

       // When radio button "Male" checked change.
       this.radioButtonFemale.setOnCheckedChangeListener(new RadioButton.OnCheckedChangeListener() {

           @Override
           public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
               doOnGameCharacterChanged(buttonView,isChecked);
           }
       });

       // When button "Save" clicked.
       this.buttonSave.setOnClickListener(new Button.OnClickListener() {
           @Override
           public void onClick(View v) {
               doSave();
           }
       });
   }


   // When radio group "Difficulty Level" checked change.
   private void doOnDifficultyLevelChanged(RadioGroup group, int checkedId) {
       int checkedRadioId = group.getCheckedRadioButtonId();

       if(checkedRadioId== R.id.radioButton_easy) {
           Toast.makeText(this,"You choose the level of difficulty: Easy",Toast.LENGTH_SHORT).show();
       } else if(checkedRadioId== R.id.radioButton_medium ) {
           Toast.makeText(this,"You choose the level of difficulty: Medium",Toast.LENGTH_SHORT).show();
       } else if(checkedRadioId== R.id.radioButton_hard) {
           Toast.makeText(this,"You choose the level of difficulty: Hard",Toast.LENGTH_SHORT).show();
       }
   }

   // When radio button checked change.
   private void doOnGameCharacterChanged(CompoundButton buttonView, boolean isChecked)  {
       RadioButton radio =(RadioButton) buttonView;

       Log.i(LOGTAG, "RadioButton "+ radio.getText()+" : "+ isChecked);
   }

   // When button "Save" clicked.
   private void doSave()  {
       int difficultyLevel = this.radioGroupDiffLevel.getCheckedRadioButtonId();
       int gameCharacter = this.radioGroupCharacter.getCheckedRadioButtonId();

       RadioButton radioButtonDiffLevel = (RadioButton) this.findViewById(difficultyLevel);
       RadioButton radioButtonGameCharacter = (RadioButton) this.findViewById(gameCharacter);

       String message ="Difficulty Level: "+ radioButtonDiffLevel.getText()
                    +", Game Character: " + radioButtonGameCharacter.getText() ;

       Toast.makeText(this,message,Toast.LENGTH_LONG).show();
   }
}
Running apps: