爲什麼我得到錯誤：致命錯誤：意外地發現零，而解包可選值？

Question

我有一個TableViewController下面，我試圖填充來自Parse的查詢請求。這個想法是，調用（我已經檢查並返回必要的信息）然後填充數組，然後使用它填充TableViewCells。這些單元格還有一個自定義類（'TableViewCell'）。

出於某種原因，'self.tableView.reloadData（）'肯定會導致崩潰。當我刪除它時，它不會崩潰，但tableviewcells不會更新解析信息。有任何想法嗎？

所有的

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 
} 

Answer 1

首先，你是不是檢查帽，imdic，價格的類型。並重復加載tableView多次循環。更換

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() 
     } 

與

for o in objects { 
      if let cap = o.objectForKey("caption") as? String, 
      let imdic = o.objectForKey("imageFile") as? [PFFile], 
      let priceInt = (o.objectForKey("price") as? String).flatMap({ Int($0))}) { 
       self.capArray.append(cap) 
       self.imageDic[cap] = imdic 
       self.priceArray.append(priceInt) 
       print(self.capArray) 
       print(self.imageDic) 
       print(self.priceArray) 
      } 
     } 
self.tableView.reloadData() 

另外，不要出列單元格的方式。更換

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 
} 

與

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell { 
    guard let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as? TableViewCell else { 
     assertionFailure("cell for index-path:\(indexPath) not found") 
     return UITableViewCell() 
    } 

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

但我認爲，問題總是可以在裏面TableViewCell類例如，captionLabel可能是零。