ios Swift - 将 Int 转换为 enum:Int
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/25276775/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Swift - Cast Int into enum:Int
提问by Marcos Duarte
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:
我对 Swift 非常陌生（本周开始使用）并且我正在从 Objective-C 迁移我的应用程序。我基本上在 Objective-C 中有以下代码可以正常工作：
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];
}
When translating it to Swift, I did the following:
将其翻译为 Swift 时，我执行了以下操作：
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)
}
By doing that, I get the error :
通过这样做，我得到了错误：
'Int' is not convertible to 'MyTimeFilter'
“Int”不可转换为“MyTimeFilter”
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?
我不知道我的方法（使用 tag 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这种类型的转换。有没有人知道如何摆脱这个错误？
Thanks!
谢谢！
回答by Jeffery Thomas
Use the rawValueinitializer: it's an initializer automatically generated for enums.
使用rawValue初始化器：它是为enums自动生成的初始化器。
self.timeFilterSelected = MyTimeFilter(rawValue: (sender as UIButton).tag)!
see: The Swift Programming Language § Enumerations
请参阅：Swift 编程语言 § 枚举
NOTE: This answer has changed. Earlier version of Swift use the class method fromRaw()to convert raw values to enumerated values.
注意：此答案已更改。早期版本的 Swift 使用类方法fromRaw()将原始值转换为枚举值。
回答by Alok
Swift 5
斯威夫特 5
@IBAction func selectFilter(sender: AnyObject) {
timeFilterSelected = MyTimeFilter(rawValue: sender.tag)
}
回答by Abraham Gonzalez
elaborating on Jeffery Thomas's answer. to be safe place a guard statement unwrap the cast before using it, this will avoid crashes
详细说明杰弗里·托马斯的回答。为安全起见，在使用之前将保护语句解开强制转换，这将避免崩溃
@IBAction func selectFilter(sender: AnyObject) {
guard let filter = MyTimeFilter(rawValue: (sender as UIButton).tag) else {
return
}
timeFilterSelected = filter
}
