跳转界面，隐藏tabbar

废话不多说，直接上代码

// 1.先设置tabbarContriller的tabBar.hidden = YES;
self.tabbarController.tabBar.hidden = YES;
// nav的push后需要隐藏tabBar
self.hidesBottomBarWhenPushed = YES;
HelpVC *vcHelp = [[HelpVC alloc]initWithNibName:HELP_XIB bundle:nil];
[self.navigationController pushViewController:vcHelp animated:YES];
// 3. 在nav的push后再重新设置NO,这样nav的pop回来时候，tabor会恢复正常显示
self.hidesBottomBarWhenPushed = NO;