ios中隐藏导航栏后，modal时出现白色闪动

从无导航页面导航进到下级页面，导航栏一闪而过，也很简单，再在压栈控制器里面再坐下处理，代码如下：

-(void)viewWillDisappear:(BOOL)animated{

    [super viewWillDisappear:animated];

    if (self.parentViewController.childViewControllers.count > 0) {

        [self.navigationController setNavigationBarHidden:YES animated:YES];

    }else{

        [self.navigationController setNavigationBarHidden:NO animated:YES];

    }
}

仅做记录！