swift - 使用 NSDate() 作为 Parse.com 的键保存字典失败

Question

我正在尝试将 [NSDate: Double] 类型的字典保存到 PFUser.currentUser's 记录中:

let user = PFUser.currentUser()!
let date = NSDate()
user["savedDictionary"] = [date: 1.0] // error, see below. ["test": 1.0] works though

user.saveInBackgroundWithBlock { (success: Bool, error: NSError?) -> Void in
    if error == nil {
        print("Dictionary uploaded!")
    } else {
       print(error)
    }
}

我得到的错误:

Caught "NSInvalidArgumentException" with reason "Invalid (non-string) key in JSON dictionary":

此错误还会导致 PFUser.currentUser 注销。

Answer 1

将日期键转换为字符串:

let date = NSDate()
let df = NSDateFormatter()

// set a format. just an example
// 2012-01-04T08:21:04.674+02:00
df.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'SSSZZZZZ"


let str = df.stringFromDate(date)
assert(str != nil)

myDict[str] = value