@interface ViewController ()      {          BOOL isflage;      }      @end            @implementation ViewController            - (void)viewDidLoad      {          [super viewDidLoad];          // Do any additional setup after loading the view from its nib.          isflage = YES;          [self.navigationController setNavigationBarHidden:isflage animated:YES];            }            #pragma mark onClick            -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event      {          isflage = !isflage;          [self.navigationController setNavigationBarHidden:isflage animated:YES];      }            @end

上述代码的实现结果就是：

先隐藏navigationController，之后点击会显示，再点击又会隐藏，超简单吧。

同样tabBarController也是同样的实现结果。