Android : Handling back button in case of multiple setContentView's

I have an activity, say FirstActivity, and multiple views that are utilized by it. Views are switched by clicking buttons on screen. Currently, I handle back button (to return to previous view) this way:

    @Override
    public boolean onKeyDown (int keyCode,KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (current == ViewNum.VIEW_DEFAULT) {
                return super.onKeyDown(keyCode,event);
            }
            else {
                setContentView(R.layout.firstactivitynew);
                configureUI();
                return true;
            }
        }
        else {
            return super.onKeyDown(keyCode,event);
        }
    }
}

This, obviously, works only if I have one nested contentView, and this is a case. However, I have a feel that there is something terribly wrong with this way of handling this. Is there any 'standard' way to handle this?