How to do it...

There are only a few changes needed to get the results:

1. First of all, open MainActivity.java and add the following constant to the class:

public static final String REQUEST_RESULT="REQUEST_RESULT"; 

2. Next, change the way the intent is called by modifying the onClickSwitchActivity() method to expect a result:

public void onClickSwitchActivity(View view) {
    EditText editText = (EditText)findViewById(R.id.editTextData);
    String text = editText.getText().toString();
    Intent intent = new Intent(this, SecondActivity.class);
    intent.putExtra(Intent.EXTRA_TEXT,text);
    startActivityForResult(intent,1);
}

3. Then, add this new method to receive the result:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode==RESULT_OK) {
        Toast.makeText(this, Integer.toString(data.getIntExtra(REQUEST_RESULT, 
                0)), Toast.LENGTH_LONG).show();
    }
}

4. Finally, modify onClickClose in SecondActivity.java to set the return value as follows:

public void onClickClose(View view) { 
    Intent returnIntent = new Intent(); 
    returnIntent.putExtra(MainActivity.REQUEST_RESULT,42); 
    setResult(RESULT_OK, returnIntent); 
    finish(); 
}