隐藏导航栏方法
1。在push到下一个Controller中或者viewDidDisappear中加入，隐藏Controller的tabBar
self.hidesBottomBarWhenPushed = NO;
或者
self.controller.hidesBottomBarWhenPushed = NO
2. 指定初始化的界面
You should never access the tab bar view of a tab bar controller directly. To configure the tabs of a tab bar controller, you assign the view controllers that provide the root view for each tab to the viewControllersproperty. The order in which you specify the view controllers determines the order in which they appear in the tab bar. When setting this property, you should also assign a value to the selectedViewController property to indicate which view controller is selected initially. (You can also select view controllers by array index using the selectedIndex property.)