swift - 使用未解析的标识符“self”(CoreData)
问题描述
我在下面使用这一行:
self.present(activityViewController, animated: true, completion: nil)
我收到一个错误 - 使用未解析的标识符“self”。关于如何解决这个问题的任何想法?对我来说,它看起来像是从属于班级,但显然做错了什么。任何帮助,将不胜感激。
import UIKit
import CoreData
class CoreDataViewController: UIViewController {
@IBOutlet weak var CoreDataView: UITableView!
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
var items:[Checkins]?
var btnnames = [""]
override func viewDidLoad() {
super.viewDidLoad()
// CoreDataView.dataSource = self
// CoreDataView.delegate = self
storeTranscription()
// Loads the current data
getTranscriptions()
// fetchCheckins()
let btn1name = btnnames[0]
let btn2name = btnnames[1]
let btn3name = btnnames[2]
let btn4name = btnnames[3]
let btn5name = btnnames[4]
let btn6name = btnnames[5]
// print(btnnames)
print(btn1name, btn2name, btn3name, btn4name, btn5name, btn6name)
}
@IBAction func export(_ sender: Any) {
exportDatabase()
}
@IBOutlet weak var Table_label: UILabel!
}
var CheckinDate: Date? = Date()
var fetchedStatsArray: [NSManagedObject] = []
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
func storeTranscription() {
//retrieve the entity that we just created
let entity = NSEntityDescription.entity(forEntityName: "Checkins", in: context)
let transc = NSManagedObject(entity: entity!, insertInto: context) as! Checkins
//set the entity values
transc.who = "Who"
transc.reason = "Reason for visit"
transc.date = CheckinDate
//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<Checkins> = Checkins.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: "who")!)")
let mdate = trans.value(forKey: "CheckinDate") 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() + "Checkins.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 checkinwho: String?
var checkinreason: String?
var export: String = NSLocalizedString("who, reason, date \n", comment: "")
for (index, itemList) in fetchedStatsArray.enumerated() {
if index <= fetchedStatsArray.count - 1 {
checkinwho = Checkins.value(forKey: "who") as! String?
checkinreason = itemList.value(forKey: "reason") as! String?
let Datevar = Checkins.value(forKey: "date") as! Date
let whostring = checkinwho
let reasonstring = checkinreason
let DateSting = "\(Datevar)"
export += "\(whostring!),\(reasonstring!),\(DateSting) \n"
}
}
print("This is what the app will export: \(export)")
return export
}
解决方案
删除此行上的 }
@IBOutlet weak var Table_label: UILabel!
}
并在此文件末尾添加另一个 }。
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