iOS NaviagtionController

//堆栈上的顶部视图控制器        62行
@property(nullable, nonatomic,readonly,strong) UIViewController *topViewController; 




/**************/
//设置导航条的标题的大小和颜色
self.navigationController.navigationBar.titleTextAttributes = @{NSFontAttributeName:[UIFont systemFontOfSize:19], NSForegroundColorAttributeName:UIColor.whiteColor};

//设置导航条左右两侧的文字的颜色(包括返回图标)
self.navigationController.navigationBar.tintColor = UIColor.whiteColor;

//自定义导航条的title
self.navigationItem.titleView = self.titleView;

//设置导航条的背景色
self.navigationController.navigationBar.barTintColor = UIColor.whiteColor;