Ios 如何在Swift 3中将核心数据导出到CSV？

我想导出实体“日志”的所有数据。我发现以下代码示例： 但这对我不起作用。它没有添加核心数据的数据，我得到的唯一输出是：“这是应用程序将导出的内容：日期、标签、类型” 我的核心数据实体是“Log”，具有以下属性：date（类型：date）、labe1（类型：String）和typ（类型：Double）。 如何将核心数据导出到CSV文件并通过邮件发送？ 谢谢你的帮助：）

我在“logs=[result]”行中得到错误：

---

使用未解析标识符“result”

这是我用于Swift 4.2的解决方案

更新以匹配存储库中的代码。

import UIKit
import CoreData

class ViewController: UIViewController {

    var itemid = 178
    var nametext = "Jones3"
    var amountDouble = 68
    var inventoryDate: Date? = Date()
    var stockStatus = true
    var fetchedStatsArray: [NSManagedObject] = []
    let context = CoreDataStack.context

    override func viewDidLoad() {
        super.viewDidLoad()
        // This add a new record every time the app is run
        storeTranscription()
        // Loads the current data
        getTranscriptions()
    }

    @IBAction func exportButton(_ sender: UIButton) {
        exportDatabase()
    }

    func storeTranscription() {
        //retrieve the entity that we just created
        let entity =  NSEntityDescription.entity(forEntityName: "ItemList", in: context)
        let transc = NSManagedObject(entity: entity!, insertInto: context) as! ItemList

        //set the entity values
        transc.itemID = Double(itemid)
        transc.productname = nametext
        transc.amount = Double(amountDouble)
        transc.stock = stockStatus
        transc.inventoryDate = inventoryDate

        //save the object
        do {
            try context.save()
            print("saved!")
        } catch let error as NSError  {
            print("Could not save \(error), \(error.userInfo)")
        } catch {

        }
    }

    func getTranscriptions () {
        //create a fetch request, telling it about the entity
        let fetchRequest: NSFetchRequest<ItemList> = ItemList.fetchRequest()

        do {
            //go get the results
            let searchResults = try context.fetch(fetchRequest)
            fetchedStatsArray = searchResults as [NSManagedObject]
            //I like to check the size of the returned results!
            print ("num of results = \(searchResults.count)")
            //You need to convert to NSManagedObject to use 'for' loops
            for trans in searchResults as [NSManagedObject] {
                //get the Key Value pairs (although there may be a better way to do that...
                print("\(trans.value(forKey: "productname")!)")
                let mdate = trans.value(forKey: "inventoryDate") as! Date
                print(mdate)
            }

        } catch {
            print("Error with request: \(error)")
        }
    }

    func exportDatabase() {
        let exportString = createExportString()
        saveAndExport(exportString: exportString)
    }

    func saveAndExport(exportString: String) {
        let exportFilePath = NSTemporaryDirectory() + "itemlist.csv"
        let exportFileURL = NSURL(fileURLWithPath: exportFilePath)
        FileManager.default.createFile(atPath: exportFilePath, contents: NSData() as Data, attributes: nil)
        //var fileHandleError: NSError? = nil
        var fileHandle: FileHandle? = nil
        do {
            fileHandle = try FileHandle(forWritingTo: exportFileURL as URL)
        } catch {
            print("Error with fileHandle")
        }

        if fileHandle != nil {
            fileHandle!.seekToEndOfFile()
            let csvData = exportString.data(using: String.Encoding.utf8, allowLossyConversion: false)
            fileHandle!.write(csvData!)

            fileHandle!.closeFile()

            let firstActivityItem = NSURL(fileURLWithPath: exportFilePath)
            let activityViewController : UIActivityViewController = UIActivityViewController(
                activityItems: [firstActivityItem], applicationActivities: nil)

            activityViewController.excludedActivityTypes = [
                UIActivity.ActivityType.assignToContact,
                UIActivity.ActivityType.saveToCameraRoll,
                UIActivity.ActivityType.postToFlickr,
                UIActivity.ActivityType.postToVimeo,
                UIActivity.ActivityType.postToTencentWeibo
            ]

            self.present(activityViewController, animated: true, completion: nil)
        }
    }

    func createExportString() -> String {
        var itemIDvar: NSNumber?
        var productNamevar: String?
        var amountvar: NSNumber?
        var stockvar: Bool?

        var export: String = NSLocalizedString("itemID, productName, Amount \n", comment: "")
        for (index, itemList) in fetchedStatsArray.enumerated() {
            if index <= fetchedStatsArray.count - 1 {
                itemIDvar = itemList.value(forKey: "itemID") as! NSNumber?
                productNamevar = itemList.value(forKey: "productname") as! String?
                amountvar = itemList.value(forKey: "amount") as! NSNumber?
                stockvar = itemList.value(forKey: "stock") as! Bool?
                let inventoryDatevar = itemList.value(forKey: "inventoryDate") as! Date
                let itemIDString = itemIDvar
                let procductNameSting = productNamevar
                let amountSting = amountvar
                let stockSting = stockvar
                let inventoryDateSting = "\(inventoryDatevar)"
                export += "\(itemIDString!),\(procductNameSting!),\(stockSting!),\(amountSting!),\(inventoryDateSting) \n"
            }
        }
        print("This is what the app will export: \(export)")
        return export
    }   
}

导入UIKit
导入CoreData
类ViewController:UIViewController{
var itemid=178
var nametext=“Jones3”
var amountDouble=68
var inventoryDate:日期？=日期（）
var stockStatus=true
var FETCHEDTSTATSARRAY:[NSManagedObject]=[]
让context=CoreDataStack.context
重写func viewDidLoad（）{
super.viewDidLoad（）
//这将在每次运行应用程序时添加新记录
storeTranscription（）
//加载当前数据
getTranscriptions（）
}
@iAction func exportButton（\发送方：UIButton）{
exportDatabase（）
}
func{
//检索我们刚刚创建的实体
让entity=NSEntityDescription.entity（forEntityName:“ItemList”，在：context中）
将transc=NSManagedObject（entity:entity！，insertInto:context）设为！ItemList
//设置实体值
transc.itemID=Double（itemID）
transc.productname=nametext
交易金额=双倍（金额双倍）
transc.stock=stockStatus
transc.inventoryDate=inventoryDate
//保存对象
做{
尝试context.save（）
打印（“已保存！”）
}将let错误捕获为NSError{
打印（“无法保存\（错误），\（错误.用户信息）”）
}抓住{
}
}
func getTranscriptions（）{
//创建一个获取请求，告诉它有关实体的信息
let fetchRequest:NSFetchRequest=ItemList.fetchRequest（）
做{
//去看看结果
让searchResults=try context.fetch（fetchRequest）
fetchedStatsArray=搜索结果为[NSManagedObject]
//我喜欢检查返回结果的大小！
打印（“结果数=\（searchResults.count）”）
//您需要转换为NSManagedObject才能使用“for”循环
用于将搜索结果转换为[NSManagedObject]{
//获取键值对（尽管可能有更好的方法。。。
打印（\（trans.value（forKey:productname）！）
让mdate=trans.value（forKey:“inventoryDate”）作为！日期
打印（mdate）
}
}抓住{
打印（“请求错误：\（错误）”）
}
}
func exportDatabase（）{
让exportString=createExportString（）
保存和导出（导出字符串：导出字符串）
}
func saveAndExport（导出字符串：字符串）{
让exportFilePath=NSTemporaryDirectory（）+“itemlist.csv”
让exportFileURL=NSURL（fileURLWithPath:exportFilePath）
FileManager.default.createFile（atPath:exportFilePath，内容：NSData（）作为数据，属性：nil）
//var fileHandleError:NSError？=nil
var fileHandle:fileHandle？=nil
做{
fileHandle=try fileHandle（forWritingTo:exportFileURL作为URL）
}抓住{
打印（“文件句柄错误”）
}
如果fileHandle！=nil{
fileHandle！.seekToEndOfFile（）
让csvData=exportString.data（使用：String.Encoding.utf8，allowLossyConversion:false）
fileHandle！.write（csvData！）
fileHandle！.closeFile（）文件
让firstActivityItem=NSURL（fileURLWithPath:exportFilePath）
让activityViewController:UIActivityViewController=UIActivityViewController(
activityItems:[firstActivityItem]，应用程序活动：无）
activityViewController.excludedActivityTypes=[
UIActivity.ActivityType.assignToContact，
UIActivity.ActivityType.saveToCameraRoll，
UIActivity.ActivityType.PostToflicker，
UIActivity.ActivityType.postToVimeo，
UIActivity.ActivityType.postToTencentWeibo
]
self.present（activityViewController，动画：true，完成：nil）
}
}
func createExportString（）->String{
var itemIDvar:NSNumber？
var PRODUCTNAME var:字符串？
var数量var:NSNumber？
瓦尔：布尔？
变量导出：String=NSLocalizedString（“itemID，productName，Amount\n”，注释：“”）
对于fetchedStatsArray.enumerated（）中的（索引、项列表）{
如果索引这是我用于Swift 4.2的解决方案

更新以匹配存储库中的代码。

import UIKit
import CoreData

class ViewController: UIViewController {

    var itemid = 178
    var nametext = "Jones3"
    var amountDouble = 68
    var inventoryDate: Date? = Date()
    var stockStatus = true
    var fetchedStatsArray: [NSManagedObject] = []
    let context = CoreDataStack.context

    override func viewDidLoad() {
        super.viewDidLoad()
        // This add a new record every time the app is run
        storeTranscription()
        // Loads the current data
        getTranscriptions()
    }

    @IBAction func exportButton(_ sender: UIButton) {
        exportDatabase()
    }

    func storeTranscription() {
        //retrieve the entity that we just created
        let entity =  NSEntityDescription.entity(forEntityName: "ItemList", in: context)
        let transc = NSManagedObject(entity: entity!, insertInto: context) as! ItemList

        //set the entity values
        transc.itemID = Double(itemid)
        transc.productname = nametext
        transc.amount = Double(amountDouble)
        transc.stock = stockStatus
        transc.inventoryDate = inventoryDate

        //save the object
        do {
            try context.save()
            print("saved!")
        } catch let error as NSError  {
            print("Could not save \(error), \(error.userInfo)")
        } catch {

        }
    }

    func getTranscriptions () {
        //create a fetch request, telling it about the entity
        let fetchRequest: NSFetchRequest<ItemList> = ItemList.fetchRequest()

        do {
            //go get the results
            let searchResults = try context.fetch(fetchRequest)
            fetchedStatsArray = searchResults as [NSManagedObject]
            //I like to check the size of the returned results!
            print ("num of results = \(searchResults.count)")
            //You need to convert to NSManagedObject to use 'for' loops
            for trans in searchResults as [NSManagedObject] {
                //get the Key Value pairs (although there may be a better way to do that...
                print("\(trans.value(forKey: "productname")!)")
                let mdate = trans.value(forKey: "inventoryDate") as! Date
                print(mdate)
            }

        } catch {
            print("Error with request: \(error)")
        }
    }

    func exportDatabase() {
        let exportString = createExportString()
        saveAndExport(exportString: exportString)
    }

    func saveAndExport(exportString: String) {
        let exportFilePath = NSTemporaryDirectory() + "itemlist.csv"
        let exportFileURL = NSURL(fileURLWithPath: exportFilePath)
        FileManager.default.createFile(atPath: exportFilePath, contents: NSData() as Data, attributes: nil)
        //var fileHandleError: NSError? = nil
        var fileHandle: FileHandle? = nil
        do {
            fileHandle = try FileHandle(forWritingTo: exportFileURL as URL)
        } catch {
            print("Error with fileHandle")
        }

        if fileHandle != nil {
            fileHandle!.seekToEndOfFile()
            let csvData = exportString.data(using: String.Encoding.utf8, allowLossyConversion: false)
            fileHandle!.write(csvData!)

            fileHandle!.closeFile()

            let firstActivityItem = NSURL(fileURLWithPath: exportFilePath)
            let activityViewController : UIActivityViewController = UIActivityViewController(
                activityItems: [firstActivityItem], applicationActivities: nil)

            activityViewController.excludedActivityTypes = [
                UIActivity.ActivityType.assignToContact,
                UIActivity.ActivityType.saveToCameraRoll,
                UIActivity.ActivityType.postToFlickr,
                UIActivity.ActivityType.postToVimeo,
                UIActivity.ActivityType.postToTencentWeibo
            ]

            self.present(activityViewController, animated: true, completion: nil)
        }
    }

    func createExportString() -> String {
        var itemIDvar: NSNumber?
        var productNamevar: String?
        var amountvar: NSNumber?
        var stockvar: Bool?

        var export: String = NSLocalizedString("itemID, productName, Amount \n", comment: "")
        for (index, itemList) in fetchedStatsArray.enumerated() {
            if index <= fetchedStatsArray.count - 1 {
                itemIDvar = itemList.value(forKey: "itemID") as! NSNumber?
                productNamevar = itemList.value(forKey: "productname") as! String?
                amountvar = itemList.value(forKey: "amount") as! NSNumber?
                stockvar = itemList.value(forKey: "stock") as! Bool?
                let inventoryDatevar = itemList.value(forKey: "inventoryDate") as! Date
                let itemIDString = itemIDvar
                let procductNameSting = productNamevar
                let amountSting = amountvar
                let stockSting = stockvar
                let inventoryDateSting = "\(inventoryDatevar)"
                export += "\(itemIDString!),\(procductNameSting!),\(stockSting!),\(amountSting!),\(inventoryDateSting) \n"
            }
        }
        print("This is what the app will export: \(export)")
        return export
    }   
}

导入UIKit
导入CoreData
类ViewController:UIViewController{
var itemid=178
var nametext=“Jones3”
var amountDouble=68
var inventoryDate:日期？=日期（）
var stockStatus=true
var FETCHEDTSTATSARRAY:[NSManagedObject]=[]
让context=CoreDataStack.context
重写func viewDidLoad（）{
super.viewDidLoad（）
//这将在每次运行应用程序时添加新记录
storeTranscription（）
//加载当前数据
getTranscriptions（）
}
@iAction func exportButton（\发送方：UIButton）{
exportDatabase（）
}
func{
//检索我们刚刚创建的实体
让entity=NSEntityDescription.entity（forEntityName:“ItemList”，在：context中）
将transc=NSManagedObject（entity:entity！，insertInto:context）设为！ItemList
//设置实体值
    do {
        let results = try context.execute(fetchRequest)
    }
    catch {
        print(error)
    }

import UIKit
import CoreData

class ViewController: UIViewController {

    var itemid = 178
    var nametext = "Jones3"
    var amountDouble = 68
    var inventoryDate: Date? = Date()
    var stockStatus = true
    var fetchedStatsArray: [NSManagedObject] = []
    let context = CoreDataStack.context

    override func viewDidLoad() {
        super.viewDidLoad()
        // This add a new record every time the app is run
        storeTranscription()
        // Loads the current data
        getTranscriptions()
    }

    @IBAction func exportButton(_ sender: UIButton) {
        exportDatabase()
    }

    func storeTranscription() {
        //retrieve the entity that we just created
        let entity =  NSEntityDescription.entity(forEntityName: "ItemList", in: context)
        let transc = NSManagedObject(entity: entity!, insertInto: context) as! ItemList

        //set the entity values
        transc.itemID = Double(itemid)
        transc.productname = nametext
        transc.amount = Double(amountDouble)
        transc.stock = stockStatus
        transc.inventoryDate = inventoryDate

        //save the object
        do {
            try context.save()
            print("saved!")
        } catch let error as NSError  {
            print("Could not save \(error), \(error.userInfo)")
        } catch {

        }
    }

    func getTranscriptions () {
        //create a fetch request, telling it about the entity
        let fetchRequest: NSFetchRequest<ItemList> = ItemList.fetchRequest()

        do {
            //go get the results
            let searchResults = try context.fetch(fetchRequest)
            fetchedStatsArray = searchResults as [NSManagedObject]
            //I like to check the size of the returned results!
            print ("num of results = \(searchResults.count)")
            //You need to convert to NSManagedObject to use 'for' loops
            for trans in searchResults as [NSManagedObject] {
                //get the Key Value pairs (although there may be a better way to do that...
                print("\(trans.value(forKey: "productname")!)")
                let mdate = trans.value(forKey: "inventoryDate") as! Date
                print(mdate)
            }

        } catch {
            print("Error with request: \(error)")
        }
    }

    func exportDatabase() {
        let exportString = createExportString()
        saveAndExport(exportString: exportString)
    }

    func saveAndExport(exportString: String) {
        let exportFilePath = NSTemporaryDirectory() + "itemlist.csv"
        let exportFileURL = NSURL(fileURLWithPath: exportFilePath)
        FileManager.default.createFile(atPath: exportFilePath, contents: NSData() as Data, attributes: nil)
        //var fileHandleError: NSError? = nil
        var fileHandle: FileHandle? = nil
        do {
            fileHandle = try FileHandle(forWritingTo: exportFileURL as URL)
        } catch {
            print("Error with fileHandle")
        }

        if fileHandle != nil {
            fileHandle!.seekToEndOfFile()
            let csvData = exportString.data(using: String.Encoding.utf8, allowLossyConversion: false)
            fileHandle!.write(csvData!)

            fileHandle!.closeFile()

            let firstActivityItem = NSURL(fileURLWithPath: exportFilePath)
            let activityViewController : UIActivityViewController = UIActivityViewController(
                activityItems: [firstActivityItem], applicationActivities: nil)

            activityViewController.excludedActivityTypes = [
                UIActivity.ActivityType.assignToContact,
                UIActivity.ActivityType.saveToCameraRoll,
                UIActivity.ActivityType.postToFlickr,
                UIActivity.ActivityType.postToVimeo,
                UIActivity.ActivityType.postToTencentWeibo
            ]

            self.present(activityViewController, animated: true, completion: nil)
        }
    }

    func createExportString() -> String {
        var itemIDvar: NSNumber?
        var productNamevar: String?
        var amountvar: NSNumber?
        var stockvar: Bool?

        var export: String = NSLocalizedString("itemID, productName, Amount \n", comment: "")
        for (index, itemList) in fetchedStatsArray.enumerated() {
            if index <= fetchedStatsArray.count - 1 {
                itemIDvar = itemList.value(forKey: "itemID") as! NSNumber?
                productNamevar = itemList.value(forKey: "productname") as! String?
                amountvar = itemList.value(forKey: "amount") as! NSNumber?
                stockvar = itemList.value(forKey: "stock") as! Bool?
                let inventoryDatevar = itemList.value(forKey: "inventoryDate") as! Date
                let itemIDString = itemIDvar
                let procductNameSting = productNamevar
                let amountSting = amountvar
                let stockSting = stockvar
                let inventoryDateSting = "\(inventoryDatevar)"
                export += "\(itemIDString!),\(procductNameSting!),\(stockSting!),\(amountSting!),\(inventoryDateSting) \n"
            }
        }
        print("This is what the app will export: \(export)")
        return export
    }   
}