Question

我试图理解为什么我不能从我的字典类型的AnyObject中获取swift String。如果我执行println（fileCreationDate）它可以工作，但我需要一个实际的字符串来处理。因此，当我尝试将其转换为NSString时（因为它是一个不像String的结构，一个结构），它是零。这就是我所拥有的：

if let atts = fileManager.attributesOfItemAtPath(fileLocation.path!, error:&err) as? Dictionary<String, AnyObject> {

                println(atts)

                if let fileCreationDate:AnyObject = atts["NSFileCreationDate"] {

                    println(fileCreationDate) //prints a date
                    var mystring:NSString! = fileCreationDate as? NSString 
                    println(mystring) //prints nil
}

谢谢！

Answer 1

你必须使用if和条件强制转换为NSDate将anyObject转换为NSDate，你可以根据需要设置日期格式。

if let atts = NSFileManager.defaultManager().attributesOfItemAtPath(myUrl.path!, error:nil) as? Dictionary<String, AnyObject> {
    if let fileCreationDate = atts["NSFileCreationDate"] as? NSDate {
        println(fileCreationDate)
        let mystring = fileCreationDate.description
        println(mystring)
    }
}


extension String {
    var fileExists: Bool {
        return NSFileManager.defaultManager().fileExistsAtPath(self)
    }
    var fileAttributes: [String:AnyObject] {
        return fileExists ? NSFileManager.defaultManager().attributesOfItemAtPath(self, error:nil) as Dictionary<String, AnyObject> : [:]
    }
    var fileCreationDate:NSDate {
        return fileAttributes["NSFileCreationDate"] as NSDate
    }
    var fileGroupOwnerAccountName:String{
        return fileAttributes["NSFileGroupOwnerAccountName"] as String
    }
    var fileType: String {
        return fileAttributes["NSFileType"] as String
    }
    var fileHFSTypeCode: Int {
        return fileAttributes["NSFileHFSTypeCode"] as Int
    }
    var fileExtendedAttributes:[String:AnyObject] {
        return fileAttributes["NSFileExtendedAttributes"] as [String:AnyObject]
    }
    var fileSystemNumber: Int {
        return fileAttributes["NSFileSystemNumber"] as Int
    }
    var fileOwnerAccountName: String {
        return fileAttributes["NSFileOwnerAccountName"] as String
    }
    var fileReferenceCount: Int {
        return fileAttributes["NSFileReferenceCount"] as Int
    }
    var fileModificationDate: NSDate {
        return fileAttributes["NSFileModificationDate"] as NSDate
    }
    var fileExtensionHidden: Bool {
        return fileAttributes["NSFileExtensionHidden"] as Bool
    }
    var fileSize: Int {
        return fileAttributes["NSFileSize"] as Int
    }
    var fileGroupOwnerAccountID: Int {
        return fileAttributes["NSFileGroupOwnerAccountID"] as Int
    }
    var fileOwnerAccountID: Int {
        return fileAttributes["NSFileOwnerAccountID"] as Int
    }
    var filePosixPermissions: Int {
        return fileAttributes["NSFilePosixPermissions"] as Int
    }
    var fileHFSCreatorCode: Int {
        return fileAttributes["NSFileHFSCreatorCode"] as Int
    }
    var fileSystemFileNumber: Int {
        return fileAttributes["NSFileSystemFileNumber"] as Int
    }
}

将AnyObject转换为NSString为Swift String

1 个答案: