Ios 为什么会出现错误：致命错误：在展开可选值时意外发现nil？

我在下面有一个TableViewController，我正试图用来自Parse的查询请求填充它。这个想法是调用（我已经检查并返回了必要的信息）然后填充数组，然后我使用数组填充TableViewCells。这些单元格还有一个自定义类（“TableViewCell”）

出于某种原因，“self.tableView.reloadData（）”肯定是导致崩溃的原因。当我删除它时，它不会崩溃，但是tableviewcells不会用解析信息更新。有什么想法吗

 import UIKit
 import Parse

 class AuctionViewController: UITableViewController {

override func viewDidLoad() {
    super.viewDidLoad()

    self.tableView.registerClass(TableViewCell.self, forCellReuseIdentifier: "Cell")


} 

var capArray = [String]()
var imageDic = [String: [PFFile]]()
var priceArray = [Int]()


override func viewDidAppear(animated: Bool) {

    capArray.removeAll(keepCapacity: true)
    imageDic.removeAll(keepCapacity: true)
    priceArray.removeAll(keepCapacity: true)

    let query = PFQuery(className: "SellerObject")
    query.findObjectsInBackgroundWithBlock { (objects, error) -> Void in

        if let objects = objects {
            for o in objects {
                if o.objectForKey("caption") != nil && o.objectForKey("imageFile") != nil && o.objectForKey("price") != nil {
                let cap = o.objectForKey("caption") as? String
                    self.capArray.append(cap!)
                let imdic = o.objectForKey("imageFile") as? [PFFile]
                self.imageDic[cap!] = imdic
                let price = o.objectForKey("price") as? String
                let priceInt = Int(price!)
                self.priceArray.append(priceInt!)
                print(self.capArray)
                print(self.imageDic)
                print(self.priceArray)

            }
                self.tableView.reloadData()
            }

        }

    }


}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

// MARK: - Table view data source

override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete implementation, return the number of rows
    return capArray.count
}


override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! TableViewCell

    cell.captionLabel.text = self.capArray[indexPath.row]
    return cell
}

---

首先，您没有按类型检查cap、imdic、价格。并在循环中多次重新加载tableView。替换

for o in objects {
            if o.objectForKey("caption") != nil && o.objectForKey("imageFile") != nil && o.objectForKey("price") != nil {
            let cap = o.objectForKey("caption") as? String
                self.capArray.append(cap!)
            let imdic = o.objectForKey("imageFile") as? [PFFile]
            self.imageDic[cap!] = imdic
            let price = o.objectForKey("price") as? String
            let priceInt = Int(price!)
            self.priceArray.append(priceInt!)
            print(self.capArray)
            print(self.imageDic)
            print(self.priceArray)

        }
            self.tableView.reloadData()
        }

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
      let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! TableViewCell

      cell.captionLabel.text = self.capArray[indexPath.row]
      return cell
}

与

另外，不要以这种方式将单元格出列。替换

for o in objects {
            if o.objectForKey("caption") != nil && o.objectForKey("imageFile") != nil && o.objectForKey("price") != nil {
            let cap = o.objectForKey("caption") as? String
                self.capArray.append(cap!)
            let imdic = o.objectForKey("imageFile") as? [PFFile]
            self.imageDic[cap!] = imdic
            let price = o.objectForKey("price") as? String
            let priceInt = Int(price!)
            self.priceArray.append(priceInt!)
            print(self.capArray)
            print(self.imageDic)
            print(self.priceArray)

        }
            self.tableView.reloadData()
        }

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
      let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! TableViewCell

      cell.captionLabel.text = self.capArray[indexPath.row]
      return cell
}

与

---

但我认为问题可能总是在TableViewCell类中考虑使用自定义结构或类，而不是三个单独的数组。是否设置了self.tableView.datasource？哪个变量为零？查看调试器。是否保证价格为整数值？