ios - 用图像填充 UICollectionView 返回 nil : Swift 2

Question

我有一个 UICollectionView，其中有一个带有 UIImageView 的自定义单元格，还有一个带有 socket 的自定义类

class theCell: UICollectionViewCell { 
@IBOutlet var theImage:UIImageView!
}

我有一组 UIImage(它只有一个常量图像)。该图像位于主包中。

var tempImages = [UIImage(named: "placeholder.png" )]

委托(delegate)方法

override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return tempImages.count
}

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

    let cell = self.collectionView?.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! theCell

    //Unexpectadly found nil
    cell.theImage.image = tempImages[indexPath.row]   
    return cell   
}

Answer 1

如果你添加了这一行:

self.collectionView!.registerClass(CollectionViewCell.self, forCellWithReuseIdentifier: "cell")

然后先删除它，这里是完整的工作代码:

CollectionViewController.swift

import UIKit

class CollectionViewController: UICollectionViewController {

    var tempImages = [UIImage]()

    override func viewDidLoad() {
        super.viewDidLoad()
        tempImages.append(UIImage(named: "bg.jpg")!)
    }

    // MARK: UICollectionViewDataSource

    override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        //#warning Incomplete method implementation -- Return the number of sections
        return 1
    }


    override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        //#warning Incomplete method implementation -- Return the number of items in the section
        return tempImages.count
    }

    override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! CollectionViewCell

        // Configure the cell
        cell.theImage.image = tempImages[indexPath.row]
        println(cell.theImage.image)
        return cell
    }
}

CollectionViewCell.swift

import UIKit

class CollectionViewCell: UICollectionViewCell {


    @IBOutlet var theImage:UIImageView!

}

并且不要忘记为您的单元分配标识符:

Sample了解更多信息。