MainActivity.java

package com.dam.fran.ventanas;


import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    Button boton;
    EditText texto;

    @Override
    protected void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        boton = (Button) findViewById(R.id.button);
        texto = (EditText)findViewById(R.id.editText);

        boton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Creamos el Intent
                Intent intent =
                        new Intent(MainActivity.this, Segunda.class);

                //Creamos la información a pasar entre actividades
                Bundle b = new Bundle();
                b.putString("NOMBRE", texto.getText().toString());


                //Añadimos la información al intent
                intent.putExtras(b);

                //Iniciamos la nueva actividad
                startActivity(intent);
            }
        });


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}