修改navigationController标题的字体和颜色

// 标题字体和颜色

NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:

[UIColor whiteColor], NSForegroundColorAttributeName,

[UIFont boldSystemFontOfSize:21], NSFontAttributeName,

nil];

[self.navigationController.navigationBar setTitleTextAttributes:attributes];