【发布时间】：2019-06-26 01:36:03
【问题描述】：
基本上，我有一个应用程序，它接受用户输入（在警报控制器中的 5 个文本字段中），这些输入全部连接到一个字符串中，形成一个看起来像是 csv 文件中的一行并存储到 coredata 的形式一个实体。该实体随后将显示在表格视图中。我希望能够导出 csv 文件以通过电子邮件发送到其他地方。所有这些都将在 iOS 设备本身中完成。
我已参考 (How to Export Core Data to CSV in Swift 3?) 中的代码来执行导出 coredata 条目的代码。我的应用程序能够成功构建。从 tableview 添加和删除项目都可以正常工作。直到我点击我的导出按钮，应用程序才会崩溃。
class ViewController: UITableViewController, NSFetchedResultsControllerDelegate {
let cellId = "cellId"
fileprivate lazy var fetchedResultsController: NSFetchedResultsController<AlarmItem> = {
//create fetch request
let fetchRequest: NSFetchRequest<AlarmItem> = AlarmItem.fetchRequest()
//configure fetch request
fetchRequest.sortDescriptors = [NSSortDescriptor(key: "alarmAttributes", ascending: true)]
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
let managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
fetchedResultsController.delegate = self
return fetchedResultsController
}()
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.beginUpdates()
}
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.endUpdates()
}
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
switch(type) {
case .insert:
if let indexPath = newIndexPath {
tableView.insertRows(at: [indexPath], with: .fade)
}
break;
case .delete:
if let indexPath = indexPath {
tableView.deleteRows(at: [indexPath], with: .fade)
}
break;
case .update:
if let indexPath = indexPath, let cell = tableView.cellForRow(at: indexPath) {
configureCell(cell, at: indexPath)
}
break;
case .move:
if let indexPath = indexPath {
tableView.deleteRows(at: [indexPath], with: .fade)
}
if let newIndexPath = newIndexPath {
tableView.insertRows(at: [newIndexPath], with: .fade)
}
break;
@unknown default:
print("Something odd is happening")
}
}
override func viewDidLoad() {
super.viewDidLoad()
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
do {
try fetchedResultsController.performFetch()
} catch let err as NSError {
print("Failed to fetch items", err)
}
}
@objc func addAlarmItem(_ sender: AnyObject) {
let alertController = UIAlertController(title: "Add New Item", message: "Please fill in the blanks", preferredStyle: .alert)
let saveAction = UIAlertAction(title: "Save", style: .default) { [unowned self] action in
//combined string of attributes
let myStrings: [String] = alertController.textFields!.compactMap { $0.text }
let myText = myStrings.joined(separator: ", ")
self.save(myText)
self.tableView.reloadData()
}
let cancelAction = UIAlertAction(title: "Cancel", style: .destructive, handler: nil)
alertController.addTextField { (textField) in
textField.placeholder = "Enter Name of Engineer"
}
alertController.addTextField { (textField) in
textField.placeholder = "Enter Date of Alarm in DD/MM/YYYY"
}
alertController.addTextField { (textField) in
textField.placeholder = "Enter Time of Alarm in 24h (eg: 2300)"
}
alertController.addTextField { (textField) in
textField.placeholder = "Please indicate True/False (type True or False)"
}
alertController.addTextField { (textField) in
textField.placeholder = "Insert comments (if any), or NIL"
}
func save(_ itemName: String) {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
let managedContext = appDelegate.persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "AlarmItem", in: managedContext)!
let item = NSManagedObject(entity: entity, insertInto: managedContext)
item.setValue(itemName, forKey: "alarmAttributes")
do {
try managedContext.save()
tableView.reloadData()
} catch let err as NSError {
print("Failed to save an item", err)
}
}
@objc func exportCSV(_ sender: AnyObject) {
exportDatabase()
}
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 fileHandle: FileHandle? = nil
do {
fileHandle = try FileHandle(forUpdating: exportFileUrl as URL)
} catch {
print("filehandle has error")
}
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 alarmAttributes: String?
var export: String = NSLocalizedString("Engineer Name,Date of Alarm,Time of Alarm,True or False,Engineer Comments \n", comment: "")
for (index, AlarmItem) in fetchedStatsArray.enumerated() {
if index <= fetchedStatsArray.count - 1 {
alarmAttributes = AlarmItem.value(forKey: "alarmAttributes") as! String?
let alarmAttributeStrings = alarmAttributes
export += "\(alarmAttributeStrings ?? "0") \n"
}
}
print("the app will now print: \(export) ")
return export
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
let sectionInfo = fetchedResultsController.sections![section]
return sectionInfo.numberOfObjects
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath)
let alarmItem = fetchedResultsController.object(at: indexPath) as NSManagedObject
cell.textLabel?.text = alarmItem.value(forKeyPath: "alarmAttributes") as? String
return cell
}
func tableView(_ tableView: UITableView!, canEditRowAtIndexPath indexPath: NSIndexPath!) -> Bool {
return true
}
overr ide func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
}
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
guard editingStyle == .delete else { return }
//fetch
let toBeDeleted = fetchedResultsController.object(at: indexPath)
//delete
fetchedResultsController.managedObjectContext.delete(toBeDeleted)
do {
try fetchedResultsController.managedObjectContext.save()
} catch let err as NSError {
print("failed to save item", err)
}
}
func tableView(_tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "AlarmItem", for: indexPath)
configureCell(cell, at: indexPath)
return cell
}
func configureCell(_ cell: UITableViewCell, at indexPath: IndexPath) {
let alarmItem = fetchedResultsController.object(at: indexPath)
//configure cell
cell.textLabel?.text = alarmItem.value(forKeyPath: "alarmAttributes") as? String
}
}
这会导致“线程 1：信号 SIGABRT”错误，但我在代码中找不到任何拼写错误。
完整的错误代码：
2019-06-26 10:04:33.843955+0800 TrueFalseAlarmV3[913:13287] libMobileGestalt MobileGestalt.c:890：此平台不支持 MGIsDeviceOneOfType。 该应用程序现在将打印：工程师姓名、报警日期、报警时间、真或假、工程师评论 2019-06-26 10:31:56.087370+0800 TrueFalseAlarmV3[913:13287] [MC] systemgroup.com.apple.configurationprofiles 路径的系统组容器是 /Users/danialaqil/Library/Developer/CoreSimulator/Devices/BF0A3A59-A660 -4F1D-B0FE-F0D226479D8D/data/Containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles 2019-06-26 10:31:56.087928+0800 TrueFalseAlarmV3[913:13287] [MC] 从私人有效用户设置中读取。 2019-06-26 10:31:56.088526+0800 TrueFalseAlarmV3[913:18176] [MC] 过滤捆绑 ID 的邮件表帐户：imdadsl.TrueFalseAlarmV3，源帐户管理：1 2019-06-26 10:31:56.100398+0800 TrueFalseAlarmV3[913:18176] [MC] 过滤捆绑 ID 的邮件表帐户：imdadsl.TrueFalseAlarmV3，源帐户管理：2 2019-06-26 10:31:56.445312+0800 TrueFalseAlarmV3[913:13287] *** 由于未捕获的异常“NSGenericException”而终止应用程序，原因：“您的应用程序已呈现 UIActivityViewController ()。在其当前的 trait 环境中，具有此样式的 UIActivityViewController 的 modalPresentationStyle 是 UIModalPresentationPopover。您必须通过视图控制器的 popoverPresentationController 提供此弹出框的位置信息。您必须提供 sourceView 和 sourceRect 或 barButtonItem。如果在呈现视图控制器时不知道此信息，则可以在 UIPopoverPresentationControllerDelegate 方法 -prepareForPopoverPresentation 中提供它。 *** 首先抛出调用堆栈： (throw 调用栈在上图中
【问题讨论】：
-
您的错误是在呈现视图控制器时。鉴于堆栈跟踪，应该有更多的错误消息，它可能是关于未设置 barButtonItem 或 sourceVIew。
-
对不起，这是什么意思？我的按钮代码是这样的：navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Export CSV", style: .plain, target: self, action: #selector(exportCSV))
-
您需要显示出现在堆栈跟踪之前的完整错误消息。请将错误粘贴为文本，而不是图片。
-
我已经添加了错误。非常感谢您的帮助
标签： ios swift uiactivityviewcontroller