How to strikethrough text programmatically in android

In this tutorial implements the example strikethrough programmatically.

Activity_main.xml

<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:background="@android:color/white"

    android:padding="16dp"

    tools:context=".MainActivity" >

    <TextView

        android:id="@+id/tv"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:padding="15dp"

        android:text="Example: textview strikethrough programmatically"

        android:textSize="25dp" />

    <Button

        android:id="@+id/btn"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_below="@id/tv"

        android:text="Strike Through" />

</RelativeLayout>

MainActivity.java

package com.androidbeginner.testcode;

import android.app.Activity;

import android.graphics.Paint;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

public class MainActivity extends Activity {

       @Override

       protected void onCreate(Bundle savedInstanceState) {

              super.onCreate(savedInstanceState);

              setContentView(R.layout.registration_form);

              final TextView tv = (TextView) findViewById(R.id.tv);

              Button btn = (Button) findViewById(R.id.btn);

              btn.setOnClickListener(new View.OnClickListener() {

                     @Override

                     public void onClick(View v) {

                           tv.setPaintFlags(tv.getPaintFlags()

                                         | Paint.STRIKE_THRU_TEXT_FLAG);

                     }

              });

       }

}