ios – UICollectionView中带有自定义UICollectionViewLayout的部分标题

我正在使用具有自定义布局的UICollectionView.在两天内我不明白如何添加头到UICollectionView.我有非常简单的视图控制器(在具有自定义布局的故事板中创建)：

class ACollectionViewController: UICollectionViewController {

    enum Identifiers: String {
        case CellIdentifier = "Cell"
        case HeaderIdentifier = "Header"
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        self.collectionView.registerClass(UICollectionReusableView.self,forSupplementaryViewOfKind: UICollectionElementKindSectionHeader,withReuseIdentifier: Identifiers.HeaderIdentifier.rawValue)
    }

    // MARK: UICollectionViewDataSource
    override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return 1
    }

    override func collectionView(collectionView: UICollectionView,numberOfItemsInSection section: Int) -> Int {
        return 10
    }

    override func collectionView(collectionView: UICollectionView,cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(Identifiers.CellIdentifier.rawValue,forIndexPath: indexPath) as Cell
        cell.backgroundColor = UIColor.redColor()
        return cell
    }

    override func collectionView(collectionView: UICollectionView,viewForSupplementaryElementOfKind kind: String,atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {
        println("ip = \(indexPath.item)")
        var supplementaryView = collectionView.dequeueReusableCellWithReuseIdentifier(Identifiers.HeaderIdentifier.rawValue,forIndexPath: indexPath) as UICollectionReusableView
        supplementaryView.backgroundColor = UIColor.blueColor()
        return supplementaryView
    }

这里是我的自定义布局：

class ALayout: UICollectionViewLayout {

    override func prepareLayout() {
        super.prepareLayout()
    }

    override func collectionViewContentSize() -> CGSize {
        return self.collectionView!.bounds.size
    }

    let itemWidth = 40
    override func layoutAttributesForItemAtIndexPath(indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! {
        var attributes = UICollectionViewLayoutAttributes(forCellWithIndexPath: indexPath)

        let x: Float = Float(10) * Float(indexPath.item)
        let y: Float = Float(indexPath.item * itemWidth)
        attributes.frame = CGRect(x: CGFloat(x),y: CGFloat(y),width: CGFloat(itemWidth),height: CGFloat(itemWidth))

        return attributes
    }

    override func layoutAttributesForElementsInRect(rect: CGRect) -> [AnyObject]? {
        var attributes = [UICollectionViewLayoutAttributes]()

        let sectionsCount = self.collectionView!.dataSource!.numberOfSectionsInCollectionView!(self.collectionView!)
        for section in 0..<sectionsCount {
            /// add header
            attributes.append(self.layoutAttributesForSupplementaryViewOfKind(UICollectionElementKindSectionHeader,atIndexPath: NSIndexPath(forItem: 0,inSection: section)))

            let itemsCount = self.collectionView!.numberOfItemsInSection(section)
            for item in 0..<itemsCount {
                let indexPath = NSIndexPath(forItem: item,inSection: section)
                attributes.append(self.layoutAttributesForItemAtIndexPath(indexPath))
            }
        }

        return attributes
    }

    override func layoutAttributesForSupplementaryViewOfKind(elementKind: String,atIndexPath indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! {
        var attributes = UICollectionViewLayoutAttributes(forSupplementaryViewOfKind: elementKind,withIndexPath: indexPath)
        attributes.frame = CGRect(x: 0,y: 0,width: 320,height: 50)

        return attributes
    }
}

问题是我不明白如何正确添加section头,这个header的indexPath应该是什么.在代码中有添加标题的注释.应用程序从错误开始崩溃

2014-10-21 13:06:22.793 UICollectionViewLayout-Demo[3805:95924] *** Terminating app due to 
uncaught exception 'NSInternalInconsistencyException',reason: 'could not dequeue a view of 
kind: UICollectionElementKindCell with identifier Header - must register a nib or a class for 
the identifier or connect a prototype cell in a storyboard'

我明白,这是因为单元格具有与我要添加的section header相同的indexPath,但是标题的indexPath应该是多少？或者也许我这样做完全错了？

先谢谢你.

解决方法

您的崩溃是因为您正在使用

var supplementaryView = collectionView.dequeueReusableCellWithReuseIdentifier(Identifiers.HeaderIdentifier.rawValue,forIndexPath: indexPath) as UICollectionReusableView

尝试将标题和页脚排列(在collectionView：viewForSupplementaryElementOfKind中).改为

var supplementaryView = collectionView.dequeueReusableSupplementaryViewOfKind(kind,withReuseIdentifier:Identifiers.HeaderIdentifier.rawValue,forIndexPath: indexPath) as UICollectionReusableView

应该摆脱崩溃,所以你可以调查indexPath.但是在我的测试中,indexPath总是只是“0”.