Swift - 将Int转换为枚举：Int [英] Swift - Cast Int into enum:Int

问题描述

我是Swift的新手（本周开始），我正在从Objective-C迁移我的应用程序。我在Objective-C中基本上有以下代码可以正常工作：

I am very new to Swift (got started this week) and I'm migrating my app from Objective-C. I have basically the following code in Objective-C that works fine:

typedef enum : int {
    MyTimeFilter1Hour = 1,
    MyTimeFilter1Day = 2,
    MyTimeFilter7Day = 3,
    MyTimeFilter1Month = 4,
} MyTimeFilter;

...

- (void)selectFilter:(id)sender
{
    self.timeFilterSelected = (MyTimeFilter)((UIButton *)sender).tag;
    [self closeAnimated:YES];
}

将其翻译成Swift时，我做了以下事情：

When translating it to Swift, I did the following:

enum MyTimeFilter : Int {
    case OneHour = 1
    case OneDay = 2
    case SevenDays = 3
    case OneMonth = 4
}

...

@IBAction func selectFilter(sender: AnyObject) {
    self.timeFilterSelected = (sender as UIButton).tag as MyTimeFilter
    self.close(true)
}

通过这样做，我得到错误：

By doing that, I get the error :

'Int'不能转换为'MyTimeFilter'

'Int' is not convertible to 'MyTimeFilter'

我不知道我的方法（使用标签属性）是否是最好的，但无论如何我需要在我的应用程序的不同位置进行此类投射。有没有人知道如何摆脱这个错误？

I don't know if my approach (using the tag property) is the best, but anyway I need to do this kind of casting in different places in my app. Does anyone have an idea of how to get rid of this error?

谢谢！

推荐答案

使用 rawValue 初始值设定项：它是为 enum s自动生成的初始值设定项。

Use the rawValue initializer: it's an initializer automatically generated for enums.

self.timeFilterSelected = MyTimeFilter(rawValue: (sender as UIButton).tag)!

参见： Swift编程语言§枚举

注意：这个答案已经改变了。早期版本的Swift使用类方法 fromRaw（）将原始值转换为枚举值。

NOTE: This answer has changed. Earlier version of Swift use the class method fromRaw() to convert raw values to enumerated values.

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