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我正在尝试使用 UICollectionViewController 创建一个类似 iCalendar 的方法。现在我正在尝试添加可重用的视图作为每天的列标题。

我制作了一个故事板并添加了一个链接到此类的 UICollectionViewController：

import UIKit

class WeekViewController: UICollectionViewController, UICollectionViewDelegate
{
    let dataSource = WeekViewDataSource()
    let weekLayout = WeekViewLayout()

    override func awakeFromNib() {
        var columnHeaderViewNIB = UINib(nibName: "ColumnHeaderView", bundle: nil)
        self.collectionView?.registerNib(columnHeaderViewNIB, forSupplementaryViewOfKind: columnHeaderViewIdentifier, withReuseIdentifier: columnHeaderViewIdentifier)

        self.collectionView?.collectionViewLayout = weekLayout
        self.collectionView?.dataSource = dataSource

        super.awakeFromNib()
    }
}

ColumnHeaderView nib 实际上是一个 xib 文件，其视图包含单个标签。此视图链接到此类：

import UIKit

class ColumnHeaderView: UICollectionReusableView
{
    @IBOutlet weak var label: UILabel!
}

数据源和布局：

import UIKit

class WeekViewDataSource: NSObject, UICollectionViewDataSource {

    var events = Array<String>()

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
    {
        return 0
    }

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

    func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {
        var view: UICollectionReusableView = collectionView.dequeueReusableSupplementaryViewOfKind(UICollectionElementKindSectionHeader, withReuseIdentifier: kind, forIndexPath: indexPath) as UICollectionReusableView

        configureHeader(view, kind: kind, indexPath: indexPath)

        return view
    }

    func configureHeader(view: UICollectionReusableView, kind: String, indexPath: NSIndexPath)
    {
        if kind == columnHeaderViewIdentifier
        {
            let interval = NSTimeInterval(indexPath.item * 24 * 60 * 60)
            let now = NSDate().dateByAddingTimeInterval(interval)
            let format = NSDateFormatter()
            format.dateStyle = NSDateFormatterStyle.MediumStyle
            format.timeStyle = NSDateFormatterStyle.MediumStyle
            format.locale = NSLocale()
            format.dateFormat = "EE\ndd. MMMM"

            let headerView: ColumnHeaderView = view as ColumnHeaderView

            headerView.label.text = format.stringFromDate(now)
        }
    }
}




class WeekViewLayout: UICollectionViewLayout
{
    var DaysPerWeek = 7
    var HoursPerDay = 24
    var HeightPerHour: CGFloat = 60.0
    var DayHeaderHeight: CGFloat = 100.0
    var DayHeaderWidth: CGFloat = 120.0
    var HourHeaderWidth: CGFloat = 50.0

    override func collectionViewContentSize() -> CGSize {
        var contentWidth = HourHeaderWidth + DayHeaderHeight * CGFloat(DaysPerWeek)
        var contentHeight = DayHeaderHeight + HeightPerHour * CGFloat(HoursPerDay)

        return CGSizeMake(contentWidth, contentHeight)
    }

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

        // Column Header - Days
        var dayHeaderViewIndexPaths = indexPathsOfDayHeaderViewsInRect(rect)
        for indexPath in dayHeaderViewIndexPaths
        {
            var attributes = layoutAttributesForSupplementaryViewOfKind(columnHeaderViewIdentifier, atIndexPath: indexPath)
            layoutAttributes.append(attributes)
        }

        return layoutAttributes
    }

    override func layoutAttributesForSupplementaryViewOfKind(elementKind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! {
        var attributes = UICollectionViewLayoutAttributes(forDecorationViewOfKind: elementKind, withIndexPath: indexPath)

        if elementKind == columnHeaderViewIdentifier
        {
            attributes.frame = CGRectMake(
                HourHeaderWidth + DayHeaderWidth * CGFloat(indexPath.length),
                self.collectionView!.contentOffset.y,
                DayHeaderWidth,
                DayHeaderHeight)
        }

        return attributes
    }


    func indexPathsOfDayHeaderViewsInRect(frame: CGRect) -> [NSIndexPath]
    {
        var minDayIndex = dayIndexFromXCoord(CGRectGetMinX(frame))
        var maxDayIndex = dayIndexFromXCoord(CGRectGetMaxX(frame))

        var indexPaths = Array<NSIndexPath>()
        for i in (minDayIndex...maxDayIndex)
        {
            indexPaths.append(NSIndexPath(index: i))
        }

        return indexPaths
    }


    /*
        Helper methods
    */

    func dayIndexFromXCoord(positionX: CGFloat) -> Int
    {
        var contentWidth = collectionViewContentSize().width - HourHeaderWidth
        var widthPerDay = contentWidth / CGFloat(DaysPerWeek)
        return Int(max(0.0, (positionX - HourHeaderWidth) / widthPerDay))
    }
}

我还没有那么远，因为我陷入了一个非常基本的问题。

The ViewController doesn't register the nib and I always get this error:
2014-09-22 22:49:52.242 WeekView[4973:304060] *** Assertion failure in -[WeekView.WeekViewLayout _decorationViewForLayoutAttributes:], /SourceCache/UIKit_Sim/UIKit-3318/UICollectionViewLayout.m:1292
2014-09-22 22:49:52.244 WeekView[4973:304060] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'could not dequeue a decoration view of kind: ColumnHeaderView - must register as a class or nib or connect a prototype in a storyboard'
*** First throw call stack:
(
    0   CoreFoundation                      0x0000000100aa13f5 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x0000000102812bb7 objc_exception_throw + 45
    2   CoreFoundation                      0x0000000100aa125a +[NSException raise:format:arguments:] + 106
    3   Foundation                          0x000000010117b28f -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
    4   UIKit                               0x0000000101bb699a -[UICollectionViewLayout _decorationViewForLayoutAttributes:] + 872
    5   UIKit                               0x0000000101b982e6 -[UICollectionView _createPreparedSupplementaryViewForElementOfKind:atIndexPath:withLayoutAttributes:applyAttributes:] + 413
    6   UIKit                               0x0000000101b994da -[UICollectionView _updateVisibleCellsNow:] + 3483
    7   UIKit                               0x0000000101b9d161 -[UICollectionView layoutSubviews] + 243
    8   UIKit                               0x00000001015e7199 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 521
    9   QuartzCore                          0x0000000105f6cf98 -[CALayer layoutSublayers] + 150
    10  QuartzCore                          0x0000000105f61bbe _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
    11  QuartzCore                          0x0000000105f61a2e _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
    12  QuartzCore                          0x0000000105ecfade _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 242
    13  QuartzCore                          0x0000000105ed0bea _ZN2CA11Transaction6commitEv + 390
    14  UIKit                               0x000000010156c67d -[UIApplication _reportMainSceneUpdateFinished:] + 44
    15  UIKit                               0x000000010156d368 -[UIApplication _runWithMainScene:transitionContext:completion:] + 2642
    16  UIKit                               0x000000010156bd22 -[UIApplication workspaceDidEndTransaction:] + 179
    17  FrontBoardServices                  0x000000010507d2a3 __31-[FBSSerialQueue performAsync:]_block_invoke + 16
    18  CoreFoundation                      0x00000001009d6abc __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    19  CoreFoundation                      0x00000001009cc805 __CFRunLoopDoBlocks + 341
    20  CoreFoundation                      0x00000001009cbfc3 __CFRunLoopRun + 851
    21  CoreFoundation                      0x00000001009cba06 CFRunLoopRunSpecific + 470
    22  UIKit                               0x000000010156b799 -[UIApplication _run] + 413
    23  UIKit                               0x000000010156e550 UIApplicationMain + 1282
    24  WeekView                            0x00000001008afc0e top_level_code + 78
    25  WeekView                            0x00000001008afc4a main + 42
    26  libdyld.dylib                       0x0000000102fdd145 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

为什么会这样？我错过了什么吗？

任何帮助都会得到帮助:) 提前谢谢你

编辑：我发现了问题！这一行是错误的：

UICollectionViewLayoutAttributes(forDecorationViewOfKind: elementKind, withIndexPath: indexPath)

我试图获取装饰视图的 ViewLayoutAttributes，但它被注册为可重用视图。我改变了这条线，它又可以工作了。

4

2 回答 2

4

这样做的原因是您的布局正在请求装饰视图的布局属性，但您正在为补充视图注册 NIB。这可能有点令人困惑，因为UICollectionViewLayout在创建装饰视图时对象不与其代表对应，它只是在知道它们的物理外观不受集合内容通知的情况下创建它们。

出于这个原因，装饰视图是使用UICollectionViewLayout函数registerNib: forDecorationViewOfKind:而不是UICollectionView自身注册的。

于 2016-08-24T10:17:55.100 回答
1

那是因为在您调用 registerNib 方法时未设置您的插座。将您的代码移动到 viewDidLoad。由于 self.collectionView 是可选类型，因此 swift 编译器无法捕捉到这一点。

于 2014-09-22T21:11:43.260 回答