UICollectionView -动态细胞高度？
UICollectionView -动态细胞高度？
提问于 2015-01-27 01:38:04
我需要显示一堆具有不同高度的collectionViewCells。视图太复杂了，我不想手动计算期望的高度。我想执行自动布局来计算单元格高度。
在dequeueReusableCellWithReuseIdentifier之外调用cellForItemAtIndexPath会破坏collectionView并导致其崩溃
另一个问题是单元格不在单独的xib中，所以我不能手动实例化一个临时的单元格并使用它来计算高度。
有什么解决办法吗？
public func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
var cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellIdentifier, forIndexPath: indexPath) as UICollectionViewCell
configureCell(cell, item: items[indexPath.row])
cell.contentView.setNeedsLayout()
cell.contentView.layoutIfNeeded()
return cell.contentView.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize)
}编辑：
一旦调用dequeueReusableCellWithReuseIdentifier，就会发生崩溃。如果我不调用该方法，而是返回一个大小，那么一切都很好，单元格的出现没有计算出的大小。
在流布局中不支持负或零大小。
2015-01-26 18:24:34.231 [13383:9752256] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 1 beyond bounds [0 .. 0]'
*** First throw call stack:
(
0 CoreFoundation 0x00000001095aef35 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x0000000109243bb7 objc_exception_throw + 45
2 CoreFoundation 0x0000000109499f33 -[__NSArrayM objectAtIndex:] + 227
3 UIKit 0x0000000107419d9c -[UICollectionViewFlowLayout _getSizingInfos] + 842
4 UIKit 0x000000010741aca9 -[UICollectionViewFlowLayout _fetchItemsInfoForRect:] + 526
5 UIKit 0x000000010741651f -[UICollectionViewFlowLayout prepareLayout] + 257
6 UIKit 0x000000010742da10 -[UICollectionViewData _prepareToLoadData] + 67
7 UIKit 0x00000001074301c6 -[UICollectionViewData layoutAttributesForItemAtIndexPath:] + 44
8 UIKit 0x00000001073fddb1 -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:viewCategory:] + 248
9 0x00000001042b824c _TFC1228BasePaginatingViewController14collectionViewfS0_FTCSo16UICollectionView6layoutCSo22UICollectionViewLayout22sizeForItemAtIndexPathCSo11NSIndexPath_VSC6CGSize + 700
10 0x00000001042b83d4 _TToFC1228BasePaginatingViewController14collectionViewfS0_FTCSo16UICollectionView6layoutCSo22UICollectionViewLayout22sizeForItemAtIndexPathCSo11NSIndexPath_VSC6CGSize + 100
11 UIKit 0x0000000107419e2e -[UICollectionViewFlowLayout _getSizingInfos] + 988
12 UIKit 0x000000010741aca9 -[UICollectionViewFlowLayout _fetchItemsInfoForRect:] + 526
13 UIKit 0x000000010741651f -[UICollectionViewFlowLayout prepareLayout] + 257
14 UIKit 0x000000010742da10 -[UICollectionViewData _prepareToLoadData] + 67
15 UIKit 0x000000010742e0e9 -[UICollectionViewData validateLayoutInRect:] + 54
16 UIKit 0x00000001073f67b8 -[UICollectionView layoutSubviews] + 170
17 UIKit 0x0000000106e3c973 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 521
18 QuartzCore 0x0000000106b0fde8 -[CALayer layoutSublayers] + 150
19 QuartzCore 0x0000000106b04a0e _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
20 QuartzCore 0x0000000106b0487e _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
21 QuartzCore 0x0000000106a7263e _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 242
22 QuartzCore 0x0000000106a7374a _ZN2CA11Transaction6commitEv + 390
23 QuartzCore 0x0000000106a73db5 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 89
24 CoreFoundation 0x00000001094e3dc7 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
25 CoreFoundation 0x00000001094e3d20 __CFRunLoopDoObservers + 368
26 CoreFoundation 0x00000001094d9b53 __CFRunLoopRun + 1123
27 CoreFoundation 0x00000001094d9486 CFRunLoopRunSpecific + 470
28 GraphicsServices 0x000000010be869f0 GSEventRunModal + 161
29 UIKit 0x0000000106dc3420 UIApplicationMain + 1282
30 0x000000010435c709 main + 169
31 libdyld.dylib 0x000000010a0f2145 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSExceptionStack Overflow用户
发布于 2017-04-21 16:38:09
按照bolnad 回答到第4步。
然后将所有其他步骤替换为：
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
// Configure your cell
sizingNibNew.configureCell(data as! CustomCellData, delegate: self)
// We use the full width minus insets
let width = collectionView.frame.size.width - collectionView.sectionInset.left - collectionView.sectionInset.right
// Constrain our cell to this width
let height = sizingNibNew.systemLayoutSizeFitting(CGSize(width: width, height: .infinity), withHorizontalFittingPriority: UILayoutPriorityRequired, verticalFittingPriority: UILayoutPriorityFittingSizeLevel).height
return CGSize(width: width, height: height)
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/28161839
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