Java Android Program to Change the Displayed Text alongside the Application Icon at Runtime

package com.example.change_text_displayed_action_bar;
 
import android.annotation.SuppressLint;
import android.app.ActionBar;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
 
@SuppressLint("NewApi")
public class MainActivity extends Activity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button change = (Button)findViewById(R.id.button1);
        change.setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                ActionBar actionBar = getActionBar();
                actionBar.setSubtitle("Changed text");
                actionBar.setTitle("And the magic happens!!!!"); 
            }
        });
    }
 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
 
}