Radio button and Checkbox widget in Android

 RadioButton:-

This widget is used to choose a single option in a group of options.

Android provides <RadioGroup> class to manage RadioButton Grouping and SubGrouping.

<RadioButton>:  class is used to provide a RadioButton view on Android Activity.

Example of RadioButton

Code for Activity Design File:-

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    android:paddingTop="120dp"
    tools:context=".MainActivity9">

    <RadioGroup
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Basic Course"
            android:id="@+id/rbbasic">

        </RadioButton>
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Advance Course"
            android:id="@+id/rbadvance">

        </RadioButton>

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Placement Course"
            android:id="@+id/rbplacement">

        </RadioButton>
    </RadioGroup>


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click"
        android:id="@+id/btnradio">

    </Button>
</LinearLayout>

Code for Activity Class File

package com.example.additionapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.Toast;

public class MainActivity9 extends AppCompatActivity {

    RadioButton rb1,rb2,rb3;
    Button btn;
    String s="";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main9);
        rb1 = findViewById(R.id.rbbasic);
        rb2 = findViewById(R.id.rbadvance);
        rb3 = findViewById(R.id.rbplacement);
        btn = findViewById(R.id.btnradio);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               if(rb1.isChecked())
               {
                   s = rb1.getText().toString();
               }
               else if(rb2.isChecked())
               {
                   s = rb2.getText().toString();
               }
               else
               {
                   s = rb3.getText().toString();
               }

               Toast.makeText(getApplicationContext(),s,Toast.LENGTH_SHORT).show();
            }


        });

    }
}

Checkbox widget:-

We can choose multiple options in a group of options,  Android provides Checkbox class to implement Checkbox Widget in the android application.

<Checkbox>

Checkbox provide is a checked method to check that checkbox is checked or not, if it is checked then it returns true otherwise it returns false.

StringBuffer class will be used to store multiple String type data under the checkbox.

Syntax of StringBuffer

StringBuffer sb = new StringBuffer();

Example of CheckBox:-

Code of Design File or XML File:-

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity10">

    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/chkc"
        android:text="C"></CheckBox>
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/chkcpp"
        android:text="CPP"></CheckBox>
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/chkds"
        android:text="DS"></CheckBox>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click"
        android:onClick="fun"
        android:id="@+id/btnchk">

    </Button>

</LinearLayout>

Code of Java or Activity File:-

package com.example.additionapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;

public class MainActivity10 extends AppCompatActivity {


    CheckBox chk1,chk2,chk3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main10);
        chk1 = findViewById(R.id.chkc);
        chk2 = findViewById(R.id.chkcpp);
        chk3 = findViewById(R.id.chkds);

    }

    public  void fun(View v)
    {
        StringBuffer sb = new StringBuffer();
        if(chk1.isChecked())
        {
            sb.append(chk1.getText().toString() + " ");
        }
        if(chk2.isChecked())
        {
            sb.append(chk2.getText().toString() + " ");
        }
        if(chk3.isChecked())
        {
            sb.append(chk3.getText().toString() + " ");
        }

        Toast.makeText(getApplicationContext(),sb.toString(), Toast.LENGTH_SHORT).show();
    }
}