Question

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：

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：

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：

'Int'不能转换为'MyTimeFilter'

我不知道我的方法（使用标签属性）是否最好，但无论如何我需要在我的应用程序中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？

谢谢！

Answer 1

使用rawValue初始值设定项：它是为enum自动生成的初始值设定项。

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

请参阅：The Swift Programming Language § Enumerations

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。

Answer 2

使用Enum进行比较，如下所示：

enum LoanType: Int {
    case FHA , VA, CONS, CASH
}
var loanType = LoanType.FHA

比较：

if loanType == .FHA
     {
      print("FHA")
     }

改变价值：

loanType = .CASH

Answer 3

详细说明Jeffery Thomas的答案。为了安全起见，请在使用前放置一个保护声明，将其解开，这样可以避免崩溃

{


"mapping": {
    "_doc": {
      "properties": {
        "@timestamp": {
          "type": "date"
        },
        "@version": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "address": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "city_code": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "contact_no": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "date_added": {
          "type": "date"
        },
        "date_updated": {
          "type": "date"
        },
        "featured": {
          "type": "long"
        },
        "id": {
          "type": "long"
        },
        "location_id": {
          "type": "long"
        },
        "main_cate": {
          "type": "long"
        },
        "name": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "slug": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "source": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "state_code": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },
        "status": {
          "type": "long"
        },
        "zip_code": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        }
      }
    }
  }
}

Swift - 将Int转换为枚举：Int

3 个答案: