In the below code first I have added a Switch button in main layout. Here I have created two-state toggle switch that can select between two options. The user may drag the thumb back and forth to choose the selected option. In MainActivity I have used onCheckedChanged method and toast function. See the below code it will clearly described how to make On/Off switch button .

Step(1)-Main.xml layout-

<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:layout_marginTop="100dp"
    android:padding="5dp"
    tools:context=".MainActivity" >

    <Switch
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Switch"
    android:id="@+id/mySwitch"

    android:layout_centerHorizontal="true"
        android:checked="false" />

    android:layout_alignParentLeft=true
    android:layout_alignParentTop=true
    android:layout_marginLeft=48dp
    android:layout_marginTop=26dp
    android:height=50dp
    android:text=@string/switch_text
    android:textSize=50sp
    android:switchMinWidth=70sp
    android:switchPadding=60sp/>
</RelativeLayout>

Step(2)-MainActivity-

public class MainActivity extends Activity {
    private Switch mySwitch;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mySwitch=(Switch)findViewById(R.id.mySwitch);

        mySwitch.setChecked(true);
     mySwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
         @Override
     public void onCheckedChanged(CompoundButton buttonView,boolean isChecked){

             if(isChecked){
                 Toast.makeText(getApplicationContext(),
                         "Notification Switch is Off",Toast.LENGTH_SHORT).show();
             }
         }
         });
     }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

}