Android - recoger parametros

Intent i = new Intent(this, Mascota2Activity.class);

        startActivityForResult(i,this.requestCode);

@Override

    protected void onActivityResult(int requestCode, int resultCode, Intent data){

        if(requestCode==this.requestCode && resultCode==RESULT_OK) {

            String res = data.getExtras().getString("resultado");

        }

    }

private static final int REQUEST_AC_A = 1;

    private static final int REQUEST_AC_B = 2;

// un botón que abre un activity    

public void boton1_click(View view) {

        Intent i = new Intent(this, ActivityA.class);

        startActivityForResult(i, REQUEST_AC_A);

    }

// otro botón, abre otra diferente

    public void boton2_click(View view) {

        Intent i = new Intent(this, ActivityB.class);

        startActivityForResult(i, REQUEST_AC_B);

    }

    @Override

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        super.onActivityResult(requestCode, resultCode, data);

        if(resultCode == RESULT_OK) {

            switch(requestCode) { // aquí se usa para ver cual terminó

                case REQUEST_AC_A:

                    // procesar el retorno de la ActivityA

                break;

                case REQUEST_AC_B:

                    // procesar el retorno de la ActivityB

                break;

            }

        }

    }

package charly.izquierdofp.es.curso;

import android.content.Intent;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.EditText;

import android.widget.ImageView;

import android.widget.LinearLayout;

import android.widget.RadioGroup;

public class Mascota1Activity extends AppCompatActivity {

    EditText txtNombre;

    RadioGroup rg;

    int requestCode = 1;

    LinearLayout layout;

    ImageView img;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_mascota1);

        txtNombre = (EditText) findViewById(R.id.txtNombre);

        rg = (RadioGroup) findViewById(R.id.RbSexo);

        layout = (LinearLayout) findViewById(R.id.layout);

    }

    /*@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_t4_a17, 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.activity_mascota1) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

    public void PulsaBoton(View view) {

        Intent i = new Intent(this, Mascota2Activity.class);

        i.putExtra("nombre", txtNombre.getText().toString());

        String sexo = "o";

        if (rg.getCheckedRadioButtonId() == R.id.RbFemenino)

            sexo = "a";

        i.putExtra("sexo", sexo);

        startActivityForResult(i, requestCode);

    }

    @Override

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode == this.requestCode && resultCode == RESULT_OK) {

            int id = data.getExtras().getInt("id");

            layout.removeView(img);

            img = new ImageView(this);

            switch (id) {

                case R.id.Perro:

                    img.setImageResource(R.drawable.perro);

                    break;

                case R.id.Gato:

                    img.setImageResource(R.drawable.gato);

                    break;

                case R.id.Hamster:

                    img.setImageResource(R.drawable.hamster);

                    break;

                case R.id.Pez:

                    img.setImageResource(R.drawable.pez);

                    break;

            }

            layout.addView(img);

        }

    }

}

img = new ImageView(this);