As your child Activity is just on the top of your Parent Activity, no need of this method
NavUtils.navigateUpFromSameTask(this);
write like
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == android.R.id.home) {
Intent result = new Intent((String) null);
result.putExtra(MyConstants.INTENT_EXTRA_RESULT, true);
setResult(RESULT_OK, result);
finish();
return true;
} else {
return super.onOptionsItemSelected(item);
}
}
finish your Child Activity when home button is pressed.