我正在为iOS 8编码.
我有一个UICollectionReusableView,它被用作UICollectionView的头
class UserHeader: UICollectionReusableView { ... }
我的视图集合做了一些事情:
在viewDidLoad中加载NIB
override func viewDidLoad() { super.viewDidLoad() resultsCollectionView.registerNib(UINib(nibName: "UserHeader",bundle: nil),forSupplementaryViewOfKind: UICollectionElementKindSectionHeader,withReuseIdentifier: "UserHeader") }
在referenceSizeforHeaderInSection中设置标题高度.
func collectionView(collectionView: UICollectionView,layout collectionViewLayout: UICollectionViewLayout,referenceSizeforHeaderInSection section: Int) -> CGSize { return CGSizeMake(0,500) }
但是,我的UserHeader视图包含许多在运行时高度变化的UILabel,UIViews,如何为referenceSizeforHeaderInSection指定动态的高度?或者,如果我不想在iOS 8中使用referenceSizeforHeaderInSection进行自动调整大小,请告诉我应该使用的内容.提前致谢.
为了完整起见,这是我加载视图的方式,但我不确定这是否与此讨论相关:
func collectionView(collectionView: UICollectionView!,viewForSupplementaryElementOfKind kind: String!,atIndexPath indexPath: NSIndexPath!) -> UICollectionReusableView! { var reusableview:UICollectionReusableView = UICollectionReusableView() if (kind == UICollectionElementKindSectionHeader) { let userHeaderView = collectionView.dequeueReusableSupplementaryViewOfKind(UICollectionElementKindSectionHeader,withReuseIdentifier: "UserHeader",forIndexPath: indexPath) as! UserHeader ... extra code to modify UserHeader reusableview = userHeaderView } return reusableview }
解决方法
我遇到了类似的问题并通过在视图中使用NSLayoutConstraints来修复它,以指定标题视图的高度.在视图控制器中,我然后配置集合视图的标题:
fileprivate var expectedSectionHeaderFrame = CGRect.zero let headerIdentifier = "HeaderView" func calculateHeaderFrame() -> CGRect { headerView.setNeedsLayout() headerView.layoutIfNeeded() let expectedHeaderSize = CGSize(width: view.bounds.width,height: headerView.systemLayoutSizefitting(UILayoutFittingCompressedSize).height) return CGRect(origin: .zero,size: expectedHeaderSize) } func collectionView(_ collectionView: UICollectionView,referenceSizeforHeaderInSection section: Int) -> CGSize { expectedSectionHeaderFrame = calculateHeaderFrame() return expectedSectionHeaderFrame.size } func collectionView(_ collectionView: UICollectionView,viewForSupplementaryElementOfKind kind: String,at indexPath: IndexPath) -> UICollectionReusableView { guard kind == UICollectionElementKindSectionHeader else { fatalError("Unexpected kind of supplementary view in (type(of: self))") } let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind,withReuseIdentifier: headerIdentifier,for: indexPath) headerView.frame = expectedSectionHeaderFrame return headerView }