onclicknotregistering

package com.example.admin.myapplication;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;


public class MyActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);
    }

    public void changeText(){

        final Button button = (Button) findViewById(R.id.button1);
        final TextView text = (TextView)findViewById(R.id.largetext);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                button.setText("Button has been pressed");
                text.setText("The large text has been changed");
            }
        });

    }
}