让UIBarButtonItem的image显示自身颜色,而不是

let image = UIImage(named: "设置icon")?.imageWithRenderingMode(UIImageRenderingMode.AlwaysOriginal)
self.navigationItem.rightBarButtonItem = UIBarButtonItem(image: image, style: UIBarButtonItemStyle.Plain, target: self, action: "jumpToSetting")

更新Swift3

let image = UIImage(named:"设置icon")?.withRenderingMode(.alwaysOriginal)