Question

我正在构建一个Collection View来从CloudKit数据库返回图像。结果缓慢回归，但他们正在回归。但是，我得到了经典的“致命错误：在展开可选值时意外发现nil”错误，我无法弄清楚为什么或我需要修复以解决错误。有没有人对如何解决这个问题有任何建议？

我的代码如下：

class CollectionViewController: UICollectionViewController  {

@IBOutlet var myCollectionView: UICollectionView!

var image = UIImage()
var matchedSelfie =  [UIImage]()
let reuseIdentifier = "MyCell"

override func viewDidLoad() {
    super.viewDidLoad()
   // self.canDisplayBannerAds = true


    println("Loading")

    var countedImages = matchedSelfie
    let publicDB = CKContainer.defaultContainer().publicCloudDatabase
    print(publicDB)

    let data = CKRecord(recordType: "theUsers")
    let pred = NSPredicate(format: "TRUEPREDICATE")
    let myQuery = CKQuery(recordType: "theUsers", predicate: pred)


    publicDB.performQuery(myQuery, inZoneWithID: nil) {
        results, error in
        println("Results from publicDB Query: \(results)")

        if error != nil {
            println(error)

        } else {
            for record in results {
                if var aselfie = record.objectForKey("selfie") as CKAsset! {
                    if var url = aselfie.fileURL {
                        var imageData = UIImage(contentsOfFile: url.path!)!
                       self.matchedSelfie.append(imageData)
                    }

                    println(self.matchedSelfie)
                    println("total selfies: \(self.matchedSelfie.count)")
                    var cellscount = self.matchedSelfie.count
                    }
                }
            }


    println("Done Loading")
     self.myCollectionView.reloadData()
        }
    }//View Did Load

 func collectionView(collectionView: UICollectionView, numberOfSectionsInCollectionView: Int) -> Int {
    self.myCollectionView.reloadData()
    return 1
}


    override func collectionView(collectionView: UICollectionView, numberOfItemsInSection: Int) -> Int {
        self.myCollectionView.reloadData()
    println("Selfies: \(self.matchedSelfie.count)")
    println(matchedSelfie.count)
     myCollectionView.reloadData()
    return self.matchedSelfie.count

    }



     override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("MyCell", forIndexPath: indexPath) as CollectionViewCell
        println("just seeing when this prints")
        cell.amatchedSelfie.image = image
        return cell
    }

}

Answer 1

你知道它失败了吗？将图像分配给cell.amatchedSelfie.image时图像的价值是多少？在分配给cell.amatchedSelfie.image

之前，你可能会检查nil

集合视图控制器崩溃而不返回图像

1 个答案: