switch in android

MAIN ACTIVITY JAVA
package com.example.viraj.aswitch;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.SwitchCompat;
import android.widget.CompoundButton;
import android.widget.Switch;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
Switch aswitch;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        aswitch=(Switch)findViewById(R.id.switch1);
        aswitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton compoundButton, boolean bviraj) {
                if (bviraj==true)
                {
                    Toast.makeText(getApplicationContext(),"THE SWITCH IS ON",Toast.LENGTH_SHORT).show();
                }
                else
                {
                    Toast.makeText(getApplicationContext(),"THE SWITCH IS Off",Toast.LENGTH_SHORT).show();
                }
            }
        });

    }
}

XML

<?xml version="1.0" encoding="utf-8"?>

<android.support.constraint.ConstraintLayout 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"

    tools:context="com.example.viraj.aswitch.MainActivity">

    <Switch

        android:id="@+id/switch1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginLeft="8dp"

        android:layout_marginRight="8dp"

        android:layout_marginTop="197dp"

        android:text="Switch....."

        app:layout_constraintLeft_toLeftOf="parent"

        app:layout_constraintRight_toRightOf="parent"

        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>