注意hidesBottomBarWhenPushed调用的时机,是在push方法调用之前调用

简单的处理方式,自定义UINavigationController重写push方法,把下面的代码放进去即可

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

    NSArray *viewControllers = self.viewControllers;
    if (viewControllers.count == 0) {
        viewController.hidesBottomBarWhenPushed = NO;
    } else {
        viewController.hidesBottomBarWhenPushed = YES;
    }
    // 必须在super之前执行hidesBottomBarWhenPushed
    [super pushViewController:viewController animated:animated];

}