04 UITabBar的隐藏问题

    // 1. 设置self.tabBarController.tabBar.hidden = YES;
    self.tabBarController.tabBar.hidden = YES;
    
    //2.如果在push跳转时需要隐藏tabBar，设置self.hidesBottomBarWhenPushed=YES;
    self.hidesBottomBarWhenPushed=YES;
    NextViewController *next = [[NextViewController alloc] init];
    [self.navigationController pushViewController:next animated:YES];
    self.hidesBottomBarWhenPushed = NO;
    // 并在push后设置self.hidesBottomBarWhenPushed = NO;
    // 这样back回来的时候，tabBar会恢复正常显示。