push時隐藏tabBar的正确使用

self.hidesBottomBarWhenPushed = YES;

有時候push過去時會正常隐藏tabBar，但是push back後tabBar又不顯示了，此時可以重寫navigationController的pushViewController方法

“`

-(void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated{

viewController.hidesBottomBarWhenPushed = YES;

[super pushViewController:viewController animated:animated];
 viewController.hidesBottomBarWhenPushed = NO;
           

}

“`