swift - 在 Swift 中创建 CSV 文件并写入文件

Question

我有一个我制作的应用程序，它有一个 UITableView 和 todoItems 作为它的 array。它工作完美，我有一个导出按钮，可以从 UITableView 数据创建一个 CSV 文件并将其通过电子邮件发送出去:

// Variables
var toDoItems:[String] = []
var convertMutable: NSMutableString!
var incomingString: String = ""
var datastring: NSString!

// Mail alert if user does not have email setup on device
func showSendMailErrorAlert() {
    let sendMailErrorAlert = UIAlertView(title: "Could Not Send Email", message: "Your device could not send e-mail.  Please check e-mail configuration and try again.", delegate: self, cancelButtonTitle: "OK")
    sendMailErrorAlert.show()
}
// MARK: MFMailComposeViewControllerDelegate Method
func mailComposeController(controller: MFMailComposeViewController, didFinishWithResult result: MFMailComposeResult, error: NSError?) {
    controller.dismissViewControllerAnimated(true, completion: nil)
}

// CSV Export Button
@IBAction func csvExport(sender: AnyObject) {
    // Convert tableView String Data to NSMutableString
    convertMutable = NSMutableString();
    for item in toDoItems
    {
        convertMutable.appendFormat("%@\r", item)
    }

    print("NSMutableString: \(convertMutable)")

    // Convert above NSMutableString to NSData
    let data = convertMutable.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)
    if let d = data { // Unwrap since data is optional and print
        print("NSData: \(d)")
    }

    //Email Functions
    func configuredMailComposeViewController() -> MFMailComposeViewController {
        let mailComposerVC = MFMailComposeViewController()
        mailComposerVC.mailComposeDelegate = self
        mailComposerVC.setSubject("CSV File Export")
        mailComposerVC.setMessageBody("", isHTML: false)
        mailComposerVC.addAttachmentData(data!, mimeType: "text/csv", fileName: "TodoList.csv")

        return mailComposerVC
    }

    // Compose Email
    let mailComposeViewController = configuredMailComposeViewController()
    if MFMailComposeViewController.canSendMail() {
        self.presentViewController(mailComposeViewController, animated: true, completion: nil)
    } else {
        self.showSendMailErrorAlert() // One of the MAIL functions
    }
}

我的问题是如何创建相同的 CSV 文件，而不是通过电子邮件将其保存到文件中？我是编程新手，仍在学习 Swift 2。我知道代码部分 (data!, mimeType: "text/csv", fileName: "TodoList.csv") 将文件创建为一个附件。我在网上查过这个，试图理解路径和目录对我来说很难。我的最终目标是让另一个 UITableView 列出这些“已保存”的 CSV 文件。有人可以帮忙吗？谢谢!

我将以下 IBAction 添加到我的项目中:

// Save Item to Memory
@IBAction func saveButton(sender: UIBarButtonItem) {
    // Convert tableView String Data to NSMutableString
    convertMutable = NSMutableString();
    for item in toDoItems
    {
        convertMutable.appendFormat("%@\r", item)
    }

    print("NSMutableString: \(convertMutable)")

    // Convert above NSMutableString to NSData
    let data = convertMutable.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)
    if let d = data { // Unwrap since data is optional and print
        print("NSData: \(d)")
    }

    let path = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSString

    func writeToFile(_: convertMutable, path: String, atomically useAuxiliaryFile: Bool, encoding enc: UInt) throws {

    }

}

Answer 1

多年来，我一直在努力寻找一个像样的简单答案。

这是我发现的创建 csv 文件的最佳方法，甚至是您希望它成为的目录并写入它。

//First make sure you know your file path, you can get it from user input or whatever
//Keep the path clean of the name for now
var filePath = "/Users/Johnson/Documents/NEW FOLDER/"
//then you need to pick your file name
let fileName = "AwesomeFile.csv"
//You should probably have some data to put in it
//You can even convert your array to a string by appending all of it's elements
let fileData = "This,is,just,some,dummy,data"

// Create a FileManager instance this will help you make a new folder if you don't have it already
let fileManager = FileManager.default 

//Create your target directory
do {
   try fileManager.createDirectory(atPath: filePath!, withIntermediateDirectories: true, attributes: nil)
   //Now it's finally time to complete the path
   filePath! += fileName!
        }
        catch let error as NSError {
            print("Ooops! Something went wrong: \(error)")
        }

//Then simply write to the file
do {
   // Write contents to file
   try fileData.write(toFile: filePath!, atomically: true, encoding: String.Encoding.utf8)
   print("Writing CSV to: \(filePath!)")
}
        catch let error as NSError {
            print("Ooops! Something went wrong: \(error)")
        }

附言。刚刚注意到这个问题是一年前的，但我希望它能帮助像我这样苦苦挣扎的新手，当他们像我一样不可避免地偶然发现它时。