我想导出我的实体“Log”的所有数据。我找到了这个代码示例： https://gist.github.com/kenechilearnscode/2d5d35f550f593332319 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，典型” 我的核心数据实体是“Log”，其属性为：date（type：date），labe1（type：String）和typ（type：Double）。 如何将核心数据导出到CSV文件并通过Mail发送？ 感谢您的帮助:)）
var logs : [Log] = []
func createExportString() -> String {
var date: NSDate? = NSDate()
var labe1: String?
var typ: Double
var export: String = NSLocalizedString("date, label, typ, \n", comment: "")
for (index, log) in logs.enumerated() {
if index < logs.count - 1 {
date = Date() as? NSDate
label = log.value(forKey: "time") as? String
typ = (log.value(forKey: "type") as? Double)!
let dateString = "\(log.date!)"
let labelString = "\(log.labe1!)"
let typeString = "\(log.typ)"
export += dateString + "," + labelString + "," + typeString + "," + "\n"
}
}
print("This is what the app will export: \(export)")
return export
}
func exportDatabase() {
var exportString = createExportString()
saveAndExport(exportString: exportString)
}
func saveAndExport(exportString: String) {
let exportFilePath = NSTemporaryDirectory() + "export.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 = [
UIActivityType.assignToContact,
UIActivityType.saveToCameraRoll,
UIActivityType.postToFlickr,
UIActivityType.postToVimeo,
UIActivityType.postToTencentWeibo
]
self.present(activityViewController, animated: true, completion: nil)
}
}
编辑：
我尝试添加这些：
let context = DatabaseController.persistentContainer.viewContext
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Log")
let result = try! NSManagedObjectContext.execute(fetchRequest)
logs = [result]
但我收到错误：“在'NSManagedObjectContext'类型上使用实例成员'execute';你的意思是使用'NSManagedObjectContext'类型的值吗？”
编辑2：
有了这些：
do {
let results = try context.execute(fetchRequest)
}
catch {
print(error)
}
我在“logs = [result]：”行中收到错误： 使用未解析的标识符'result'
答案 0 :(得分：3)
这是我用于 Swift 3 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: NSDate? = NSDate()
var stockStatus = true
var fetchedStatsArray: [NSManagedObject] = []
override func viewDidLoad() {
super.viewDidLoad()
storeTranscription()
getTranscriptions()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func exportButton(_ sender: UIButton) {
exportDatabase()
}
func getContext () -> NSManagedObjectContext {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
return appDelegate.persistentContainer.viewContext
}
func storeTranscription() {
let context = getContext()
//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 getContext().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 = [
UIActivityType.assignToContact,
UIActivityType.saveToCameraRoll,
UIActivityType.postToFlickr,
UIActivityType.postToVimeo,
UIActivityType.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
}
}