将核心数据结构导出到附加到邮件的 .csv 文件 XCODE 8.1 Swift 3
Exporting Core Data structure to .csv file attached to mail XCODE 8.1 Swift 3
我正在制作一个应用程序，它需要从核心数据中获取一个托管对象数组并将其导出到一个 csv 文件，我计划将该文件附加到使用 mfMailComposer 系统发送的电子邮件中。我将数据正确存储在核心数据系统中，并且邮件编辑器功能似乎可以正常工作。当我试图找到导出数据的正确过程时遇到了障碍。
我已经仔细研究了这两个 post 试图确定解决方案：
从 2012 年开始，似乎非常过时：
how to export Core Data to CSV
从 2016 年开始，最近，但是 swift 3 和 Xcode 8 已经发布，我担心这也已经过时了：
我一直在尝试尝试第二个 link 中提出的解决方案，但是大部分代码在输入时都被标记为不正确，所以我相信它现在已经随着升级而过时了。
下面的代码基于第二个 post，因此可能已过时，但为了提供我正在尝试完成的过程的参考...
// Called by the press of xcode UI button
@IBAction func ExportToCSV(_ sender: AnyObject)
{
// Make our mail composer controller and fill it with the proper information
let mailComposeViewController = configuredMailComposeViewController()
// If the composer is functioning properly ...
if MFMailComposeViewController.canSendMail()
{
// ... Present the generated mail composer controller
self.present(mailComposeViewController, animated: true, completion: nil)
}
else
{
// ... Otherwise, show why it is not working properly
self.showSendMailErrorAlert()
}
}
// Used to set up the body of the outgoing email
func configuredMailComposeViewController() -> MFMailComposeViewController
{
// Establish the controller from scratch
let mailComposerVC = MFMailComposeViewController()
mailComposerVC.mailComposeDelegate = self
// Set preset information included in the email
mailComposerVC.setSubject("Generic email subject")
mailComposerVC.setMessageBody("Generic email body", isHTML: false)
// Turn core data for responses into a .csv file
// Pull core data in
var CoreDataResultsList = [NSManagedObject]()
// Register the proper delegate and managed context
let appDelegate =
UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
// Pull the data from core data
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ItemResponses")
do {
let results =
try managedContext!.fetch(fetchRequest)
CoreDataResultsList = results as! [NSManagedObject]
} catch let error as NSError {
print("Could not fetch \(error), \(error.userInfo)")
}
// Take the managed object array and turn it into a .csv sring to write in the file
let csvString = writeCoreObjectsToCSV(objects: CoreDataResultsList, named: "Generic name")
let data = csvString.dataUsingEncoding(NSUTF8StringEncoding)
mailComposerVC.addAttachmentData(data, mimeType: "text/csv", fileName: "GenericFilename.csv")
return mailComposerVC
}
// Takes a managed object and writes it to the .csv file ..?
func writeCoreObjectsToCSV(objects: [NSManagedObject], named: String) -> String
{
// Make sure we have some data to export
guard objects.count > 0 else
{
return ""
}
let firstObject = objects[0]
let attribs = Array(firstObject.entity.attributesByName.keys)
// The attires.reduce function is throwing an error about originally using combine as in the second post, used auto fix, but noteworthy.
//Now gives an error that says "No '+' candidates produce the expected contextual result type NSString"
let csvHeaderString = (attribs.reduce("", {([=12=] as String) + "," + }) as NSString).substringFromIndex(1) + "\n"
// This function says that substring from index has been renamed as well as a few other lines within it
let csvArray = objects.map({object in
(attribs.map({((object.valueForKey([=12=]) ?? "NIL") as AnyObject).description}).reduce("",combine: {[=12=] + "," + }) as NSString).substringFromIndex(1) + "\n"
})
// Again with the reduce issue
let csvString = csvArray.reduce("", combine: +)
return csvHeaderString + csvString
}
新代码的底部我在第二个 post 的建议代码中评论的多个错误以及使用 xCode 的自动修复功能后的相关问题。
在此先感谢您帮助我解决这个问题。我只是在寻找将核心数据导出为 .csv 文件并将其发送出去的最新方法。谢谢！
我最终解决了这个问题。起初我不明白 .csv 文件是怎么写的，直到我看到 "comma-separated values" 的缩写。然后一切都为我点击了，我自己写了，我为头部条目做了一个更手动的路线，但以下几行的数据仍然是自动的。
以下是新工作形式的相关函数：
// Called by the press of xcode UI button
@IBAction func ExportToCSV(_ sender: AnyObject)
{
// Make our mail composer controller and fill it with the proper information
let mailComposeViewController = configuredMailComposeViewController()
// If the composer is functioning properly ...
if MFMailComposeViewController.canSendMail()
{
// ... Present the generated mail composer controller
self.present(mailComposeViewController, animated: true, completion: nil)
}
else
{
// ... Otherwise, show why it is not working properly
self.showSendMailErrorAlert()
}
}
// Used to set up the body of the outgoing email
func configuredMailComposeViewController() -> MFMailComposeViewController
{
// Establish the controller from scratch
let mailComposerVC = MFMailComposeViewController()
mailComposerVC.mailComposeDelegate = self
// Set preset information included in the email
mailComposerVC.setSubject("Generic Subject")
mailComposerVC.setMessageBody("Generic Email Body", isHTML: false)
// Turn core data for responses into a .csv file
// Pull core data in
var CoreDataResultsList = [NSManagedObject]()
// Register the proper delegate and managed context
let appDelegate =
UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
// Pull the data from core data
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ItemResponses")
do {
let results =
try managedContext!.fetch(fetchRequest)
CoreDataResultsList = results as! [NSManagedObject]
} catch let error as NSError {
print("Could not fetch \(error), \(error.userInfo)")
}
// Take the managed object array and turn it into a .csv sring to write in the file
// In doing this, we are writing just like we would to any string
let csvString = writeCoreObjectsToCSV(objects: CoreDataResultsList)
let data = csvString.data(using: String.Encoding.utf8.rawValue, allowLossyConversion: false)
mailComposerVC.addAttachmentData(data!, mimeType: "text/csv", fileName: "GenericFilename.csv")
return mailComposerVC
}
// Takes a managed object and writes it to the .csv file ..?
func writeCoreObjectsToCSV(objects: [NSManagedObject]) -> NSMutableString
{
// Make sure we have some data to export
guard objects.count > 0 else
{
return ""
}
var mailString = NSMutableString()
mailString.append("Generic Header 1, Generic Header 2, Generic Header 3")
for object in objects
{
// Put "\n" at the beginning so you don't have an extra row at the end
mailString.append("\n\(object.value(forKey: "Generic Core Data Key 1")!),\(object.value(forKey: "Generic Core Data Key 2")!), \(object.value(forKey: "Generic Core Data Key 3")!)")
}
return mailString
}
我遇到一个问题，我的一个键是包含逗号的字符串，需要一种正确的方法来避开它们。我听说双引号是怎么做的，但是插入它们没有成功。
无论如何，这是将核心数据放入数组并将其写入字符串、保存到 .csv 文件并邮寄出去的一种当前方法。这回答了我的问题，但我的下一个任务是读回数据。我不知道如何访问文件以在 iPad 上执行此操作。如果您遇到此问题并知道该怎么做，请告诉我！如果找不到解决方案，我可能会就该主题再做一个 post，然后在这个答案下面的回复中提出一个新问题和一个 link。
谢谢！
我正在制作一个应用程序，它需要从核心数据中获取一个托管对象数组并将其导出到一个 csv 文件，我计划将该文件附加到使用 mfMailComposer 系统发送的电子邮件中。我将数据正确存储在核心数据系统中，并且邮件编辑器功能似乎可以正常工作。当我试图找到导出数据的正确过程时遇到了障碍。
我已经仔细研究了这两个 post 试图确定解决方案：
从 2012 年开始，似乎非常过时： how to export Core Data to CSV
从 2016 年开始，最近，但是 swift 3 和 Xcode 8 已经发布，我担心这也已经过时了：
我一直在尝试尝试第二个 link 中提出的解决方案，但是大部分代码在输入时都被标记为不正确，所以我相信它现在已经随着升级而过时了。
下面的代码基于第二个 post，因此可能已过时，但为了提供我正在尝试完成的过程的参考...
// Called by the press of xcode UI button
@IBAction func ExportToCSV(_ sender: AnyObject)
{
// Make our mail composer controller and fill it with the proper information
let mailComposeViewController = configuredMailComposeViewController()
// If the composer is functioning properly ...
if MFMailComposeViewController.canSendMail()
{
// ... Present the generated mail composer controller
self.present(mailComposeViewController, animated: true, completion: nil)
}
else
{
// ... Otherwise, show why it is not working properly
self.showSendMailErrorAlert()
}
}
// Used to set up the body of the outgoing email
func configuredMailComposeViewController() -> MFMailComposeViewController
{
// Establish the controller from scratch
let mailComposerVC = MFMailComposeViewController()
mailComposerVC.mailComposeDelegate = self
// Set preset information included in the email
mailComposerVC.setSubject("Generic email subject")
mailComposerVC.setMessageBody("Generic email body", isHTML: false)
// Turn core data for responses into a .csv file
// Pull core data in
var CoreDataResultsList = [NSManagedObject]()
// Register the proper delegate and managed context
let appDelegate =
UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
// Pull the data from core data
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ItemResponses")
do {
let results =
try managedContext!.fetch(fetchRequest)
CoreDataResultsList = results as! [NSManagedObject]
} catch let error as NSError {
print("Could not fetch \(error), \(error.userInfo)")
}
// Take the managed object array and turn it into a .csv sring to write in the file
let csvString = writeCoreObjectsToCSV(objects: CoreDataResultsList, named: "Generic name")
let data = csvString.dataUsingEncoding(NSUTF8StringEncoding)
mailComposerVC.addAttachmentData(data, mimeType: "text/csv", fileName: "GenericFilename.csv")
return mailComposerVC
}
// Takes a managed object and writes it to the .csv file ..?
func writeCoreObjectsToCSV(objects: [NSManagedObject], named: String) -> String
{
// Make sure we have some data to export
guard objects.count > 0 else
{
return ""
}
let firstObject = objects[0]
let attribs = Array(firstObject.entity.attributesByName.keys)
// The attires.reduce function is throwing an error about originally using combine as in the second post, used auto fix, but noteworthy.
//Now gives an error that says "No '+' candidates produce the expected contextual result type NSString"
let csvHeaderString = (attribs.reduce("", {([=12=] as String) + "," + }) as NSString).substringFromIndex(1) + "\n"
// This function says that substring from index has been renamed as well as a few other lines within it
let csvArray = objects.map({object in
(attribs.map({((object.valueForKey([=12=]) ?? "NIL") as AnyObject).description}).reduce("",combine: {[=12=] + "," + }) as NSString).substringFromIndex(1) + "\n"
})
// Again with the reduce issue
let csvString = csvArray.reduce("", combine: +)
return csvHeaderString + csvString
}
新代码的底部我在第二个 post 的建议代码中评论的多个错误以及使用 xCode 的自动修复功能后的相关问题。
在此先感谢您帮助我解决这个问题。我只是在寻找将核心数据导出为 .csv 文件并将其发送出去的最新方法。谢谢！
我最终解决了这个问题。起初我不明白 .csv 文件是怎么写的，直到我看到 "comma-separated values" 的缩写。然后一切都为我点击了，我自己写了，我为头部条目做了一个更手动的路线，但以下几行的数据仍然是自动的。
以下是新工作形式的相关函数：
// Called by the press of xcode UI button
@IBAction func ExportToCSV(_ sender: AnyObject)
{
// Make our mail composer controller and fill it with the proper information
let mailComposeViewController = configuredMailComposeViewController()
// If the composer is functioning properly ...
if MFMailComposeViewController.canSendMail()
{
// ... Present the generated mail composer controller
self.present(mailComposeViewController, animated: true, completion: nil)
}
else
{
// ... Otherwise, show why it is not working properly
self.showSendMailErrorAlert()
}
}
// Used to set up the body of the outgoing email
func configuredMailComposeViewController() -> MFMailComposeViewController
{
// Establish the controller from scratch
let mailComposerVC = MFMailComposeViewController()
mailComposerVC.mailComposeDelegate = self
// Set preset information included in the email
mailComposerVC.setSubject("Generic Subject")
mailComposerVC.setMessageBody("Generic Email Body", isHTML: false)
// Turn core data for responses into a .csv file
// Pull core data in
var CoreDataResultsList = [NSManagedObject]()
// Register the proper delegate and managed context
let appDelegate =
UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
// Pull the data from core data
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ItemResponses")
do {
let results =
try managedContext!.fetch(fetchRequest)
CoreDataResultsList = results as! [NSManagedObject]
} catch let error as NSError {
print("Could not fetch \(error), \(error.userInfo)")
}
// Take the managed object array and turn it into a .csv sring to write in the file
// In doing this, we are writing just like we would to any string
let csvString = writeCoreObjectsToCSV(objects: CoreDataResultsList)
let data = csvString.data(using: String.Encoding.utf8.rawValue, allowLossyConversion: false)
mailComposerVC.addAttachmentData(data!, mimeType: "text/csv", fileName: "GenericFilename.csv")
return mailComposerVC
}
// Takes a managed object and writes it to the .csv file ..?
func writeCoreObjectsToCSV(objects: [NSManagedObject]) -> NSMutableString
{
// Make sure we have some data to export
guard objects.count > 0 else
{
return ""
}
var mailString = NSMutableString()
mailString.append("Generic Header 1, Generic Header 2, Generic Header 3")
for object in objects
{
// Put "\n" at the beginning so you don't have an extra row at the end
mailString.append("\n\(object.value(forKey: "Generic Core Data Key 1")!),\(object.value(forKey: "Generic Core Data Key 2")!), \(object.value(forKey: "Generic Core Data Key 3")!)")
}
return mailString
}
我遇到一个问题，我的一个键是包含逗号的字符串，需要一种正确的方法来避开它们。我听说双引号是怎么做的，但是插入它们没有成功。
无论如何，这是将核心数据放入数组并将其写入字符串、保存到 .csv 文件并邮寄出去的一种当前方法。这回答了我的问题，但我的下一个任务是读回数据。我不知道如何访问文件以在 iPad 上执行此操作。如果您遇到此问题并知道该怎么做，请告诉我！如果找不到解决方案，我可能会就该主题再做一个 post，然后在这个答案下面的回复中提出一个新问题和一个 link。
谢谢！