Android : Android back option in action bar

When I created an activity it automatically added a back to main activity option in the action bar. It looks like those are the functions that do it:

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

Is there a way to make it go back using finish()? Right now it looks like it resets some values that are saved and I want to keep them. When I tried working with finish() it didn't do it but i'm not sure how to use it in the action bar.