状态栏调整 ：

渲染的非常好

不是 完全隐藏， 是状态栏 背景 隐藏。

- (void)viewDidLoad {
    [super viewDidLoad];
    
[self.navigationController setNavigationBarHidden: YES ];
}

#pragma mark - 视图的 生命周期

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear: animated ];
    self.automaticallyAdjustsScrollViewInsets = NO;
    [self.navigationController.view sendSubviewToBack: self.navigationController.navigationBar ];
}

状态栏隐藏：

pragma mark - 视图的 生命周期

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear: animated ];
    if ( [self respondsToSelector: @selector(setNeedsStatusBarAppearanceUpdate) ]){
    
        [self prefersStatusBarHidden ];
        [self performSelector: @selector(setNeedsStatusBarAppearanceUpdate) ];
    }
}


- (BOOL)prefersStatusBarHidden{
    return YES;
}

http://www.jianshu.com/p/8e6973472baa