handle navigationBar hide and sh

我们只需要将需要进行导航栏隐藏与展示的vc放到baseNavigationController控制器下，并在该控制器的代理里去操作指定控制器的导航栏的隐藏即可，无需在控制器里做任何操作。
具体实现如下：

#import "BaseNavigationController.h"

#import "NoNavTargetVC.h"

@interface BaseNavigationController ()<UINavigationControllerDelegate, UIGestureRecognizerDelegate>

@end

@implementation BaseNavigationController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.delegate = self;
    
    id target = self.interactivePopGestureRecognizer.delegate;
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:target action:NSSelectorFromString(@"handleNavigationTransition:")];
    [self.view addGestureRecognizer:pan];
    self.interactivePopGestureRecognizer.enabled = NO;
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
    if (self.viewControllers.count > 0) {
        viewController.hidesBottomBarWhenPushed = YES;
    }
    [super pushViewController:viewController animated:animated];
}


#pragma mark - UINavigationControllerDelegate

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    BOOL isHideNav = [viewController isKindOfClass:[NoNavTargetVC class]];
    
    NSLog(@"isHide = %d", isHideNav);
    [self setNavigationBarHidden:isHideNav animated:YES];
}

@end

也可以这样：

在需要隐藏的VC里重写：

- (void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    
    self.navigationController.navigationBarHidden = YES;
}

- (void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    
    self.navigationController.navigationBarHidden = NO;
}