swift - 更新 xcode fatal error : unexpectedly found nil while unwrapping an Optional value 后

Question

更新后程序停止工作。

import UIKit
import CoreData

class ViewController: UIViewController, UITableViewDataSource, UINavigationControllerDelegate, UITableViewDelegate {

    var interstring = [LogItem]()

    let managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext

    var logTableView = UITableView()

    let photoVC = PhotoViewController()

    @IBOutlet weak var tableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad()
        title = "\"LogItem\""
        tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "Cell")
    }

    func tableView(tableView: UITableView,
        numberOfRowsInSection section: Int) -> Int {
            return interstring.count
    }

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

            ***let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! UITableViewCell*** - This emphasizes this part of the code

            let logItem = interstring[indexPath.row]
            cell.textLabel!.text = logItem.valueForKey("title") as? String

            return cell
    }
    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)

        let appDelegate =
        UIApplication.sharedApplication().delegate as! AppDelegate

        let managedContext = appDelegate.managedObjectContext!

        let fetchRequest = NSFetchRequest(entityName:"LogItem")

        var error: NSError?

        let fetchedResults =
        managedContext.executeFetchRequest(fetchRequest,
            error: &error) as? [LogItem]
        println("\(interstring)")

        if let results = fetchedResults {
            interstring = results
            //self.tableView.reloadData()
        } else {
            println("Could not fetch \(error), \(error!.userInfo)")
        }
    }

所有项目都是 here

Answer 1

我在更新到 swift 2 和 xcode 7 时也遇到了同样的问题。

我认为问题在于您正在尝试调用一个不存在的单元格。我通过使用自定义单元格创建 Nib 然后将标识符设置为“单元格”以及初始化 Nib 来解决问题

let identifier = "cell"
var cell: customCell! = tableView.dequeueReusableCellWithIdentifier(identifier) as? customCell

if cell == nil {

   tableView.registerNib(UINib(nibName: "customCell", bundle: nil), forCellReuseIdentifier: identifier)
   cell = tableView.dequeueReusableCellWithIdentifier(identifier) as? customCell

}

希望对你有帮助