如何在SWIFT中访问UIColor的扩展？ [英] How to access extension of UIColor in SWIFT?

问题描述

我对swift很新，并尝试创建UIColor类的扩展名为

i am very new to swift and trying to create an extension of UIColor class as

extension UIColor{

    func getCustomBlueColor() -> UIColor{

    return UIColor(red:0.043, green:0.576 ,blue:0.588 , alpha:1.00)

    }

在此之后，我将方法视为

After this i accessed the method as

btnShare.setTitleColor(UIColor.getCustomBlueColor(**UIColor**), forState: UIControlState.Normal)

我不知道我应该作为这个陈述的参数传递。

I dont know what I should pass as an argument to this statement.

推荐答案

你已经定义了一个实例方法 ，这意味着您只能在 UIColor 实例上调用
：

You have defined an instance method, which means that you can call it only on an UIColor instance:

let col = UIColor().getCustomBlueColor()
// or in your case:
btnShare.setTitleColor(UIColor().getCustomBlueColor(), forState: .Normal)

编译器错误缺少参数的发生是因为
实例方法是Swift中的Curried函数，
所以我t可以等效地被称为

The compiler error "missing argument" occurs because Instance Methods are Curried Functions in Swift, so it could equivalently be called as

let col = UIColor.getCustomBlueColor(UIColor())()

（但这样做会很奇怪，而且我只将它添加到
解释错误信息的来源来自。）

(But that would be a strange thing to do, and I have added it only to explain where the error message comes from.)

但你真正想要的是类型方法（ class func ）

extension UIColor{
    class func getCustomBlueColor() -> UIColor{
        return UIColor(red:0.043, green:0.576 ,blue:0.588 , alpha:1.00)
    }
}

被称为

let col = UIColor.getCustomBlueColor()
// or in your case:
btnShare.setTitleColor(UIColor.getCustomBlueColor(), forState: .Normal)

，无需先创建 UIColor 实例。

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