swift 3隐含使用＆＃39; self＆＃39;关闭;使用＆＃39; self。＆＃39;使捕获语义显式化

Question

我试图使用func我扩展了UIViewController。我将自我添加到不同的func的论点中，但是func没有给我＆＃34;隐含地使用＆＃39; self＆＃39;关闭;使用＆＃39; self。＆＃39;使捕获语义明确＆＃34;错误。甚至尝试应用弱自引用。 func似乎永远不会运行

宣布

数组

var managedComicsArray = [NSManagedObject]()

在viewDidLoad中：

guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {return}
    managedContext = appDelegate.persistentContainer.viewContext

按钮

@IBAction func addComicButtonTapped(_ sender: UIBarButtonItem) {

    print("add button tapped")

    weak var weakSelf = self // ADD THIS LINE AS WELL


    let alert = UIAlertController(title: "Some Title", message: "Enter a text", preferredStyle: .alert)

    alert.addTextField { (textField) in
        textField.placeholder = "Some default text"
        textField.keyboardType = .numberPad
    }

    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { [weak alert] (_) in
//            let textField = alert.textFields![0] // Force unwrapping because we know it exists.
        let textField = alert!.textFields![0]
        print("Text from textField: \(textField.text)")


        guard let grabbedNumber = Int16(textField.description) else {return}
//the func below gives the error
        weakSelf?.addRecordIfnotPresent(newIssueNumber: grabbedNumber, theManagedContext: self.managedContext, theEntityName: self.kComicEntityName, managedArray: &self.managedComicsArray)


        self.myTableView.reloadData()
    }))

    alert.addAction(UIAlertAction(title: "cancel", style: .cancel, handler: nil))

    // 4. Present the alert.
    self.present(alert, animated: true, completion: nil)


   //end of button
}

扩展方法：

func addRecordIfnotPresent(newIssueNumber: Int16, theManagedContext: NSManagedObjectContext, theEntityName: String, managedArray: inout [NSManagedObject]) {

    print("adding func started")

    let comicFetch: NSFetchRequest<Comic> = Comic.fetchRequest()
    var isPresent = true

    do {
        managedArray = try theManagedContext.fetch(comicFetch)


        if !managedArray.isEmpty {

        //*****************************************************************
        for comic in managedArray {

            var comicToCheck = Comic()
            comicToCheck = comic as! Comic

            if comicToCheck.wholeSeriesNumber == newIssueNumber {
                print("number \(newIssueNumber) is alredy present")
                return
            } else {
                isPresent = false
                print("number not present, keep on!")
            }

        }


        guard isPresent == false else {return}
        saveSingleComicWithNumber(withIssueNumber: Int(newIssueNumber), theEntityName: theEntityName, theManagedContext: theManagedContext)
        print("created Comic!")
        try theManagedContext.save()
        print("saved context!")
        //*****************************************************************

        } else {
            saveSingleComicWithNumber(withIssueNumber: Int(newIssueNumber), theEntityName: theEntityName, theManagedContext: theManagedContext)

        }










    } catch let error as NSError {
        print("Fetch error: \(error) description: \(error.userInfo)")
    }


}






func saveSingleComicWithNumber(withIssueNumber: Int, theEntityName: String, theManagedContext: NSManagedObjectContext) {
    let entity = NSEntityDescription.entity(forEntityName: theEntityName, in: theManagedContext)!

    let comicToAdd = Comic(entity: entity, insertInto: theManagedContext)


    comicToAdd.wholeSeriesNumber = Int16(withIssueNumber)
    comicToAdd.issueInCollection = false
    comicToAdd.titleOfItalianSerie = "title"

    if comicToAdd.wholeSeriesNumber == 2 {
        comicToAdd.issueInCollection = false
    }


    do {
        try theManagedContext.save()
    } catch let error as NSError {
        print("could not save. \(error), \(error.userInfo)")
    }
}