当我按下iPhone上的tabber项目（在底部）时，是否有任何功能被调用？

Say I have a tabber item a that displays a view v1, now I push sv1 while viewing v1. If I press the tabber icon at the bottom, then I have seen that it takes me back to view v1. Is it the default behavior? Is there any function called when I press tabbar item on iPhone?Say I have a tabber item a that displays a view