Ios UITabBar图标文本颜色

我如何更改UITabBar的文本颜色（如果有问题，它包含在UINavigationController中）？ 如果我写这个-

UITabBar.appearance().tintColor = UIColor.greenColor()

UITabBar.appearance().tintColor = UIColor(red: 255, green: 255, blue: 255, alpha: 1.0)

然后颜色会像预期的那样是绿色，但是如果我写这个-

UITabBar.appearance().tintColor = UIColor.greenColor()

UITabBar.appearance().tintColor = UIColor(red: 255, green: 255, blue: 255, alpha: 1.0)

文本变得不可见

同样的道理也适用于

UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.redColor()], forState:.Selected) //red color 

UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor(red: CGFloat(104), green: CGFloat(154), blue: CGFloat(26), alpha: CGFloat(1))], forState:.Selected) //invisible

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请尝试这样写：

UITabBar.appearance().tintColor = UIColor(red: 255.0/255.0, green: 255.0/255.0, blue: 255.0/255.0, alpha: 1.0)

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请尝试这样写：

UITabBar.appearance().tintColor = UIColor(red: 255.0/255.0, green: 255.0/255.0, blue: 255.0/255.0, alpha: 1.0)

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你必须将红色、绿色和蓝色除以255，如下所示

UIColor(red:255/255.0, green:255/255.0, blue: 255/255.0, alpha: 1.0)

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你必须将红色、绿色和蓝色除以255，如下所示

UIColor(red:255/255.0, green:255/255.0, blue: 255/255.0, alpha: 1.0)