swift – 为什么没有调用UICollectionView insetForSectionsAtIn
我正在寻找使用以下功能,但不幸的是它没有被调用.
func collectionView(collectionView: UICollectionView,layout collectionViewLayout: UICollectionViewFlowLayout,insetForSectionAtIndex section: Int) -> UIEdgeInsets { let cellCount = Double(collectionView.numberOfItems(inSection: section)) if let cell = collectionView.cellForItem(at: IndexPath(row: 0,section: section)) { let cellWidth = Double(cell.frame.size.width) let totalCellWidth = cellWidth * cellCount let cellSpacing = Double(collectionViewLayout.minimumInteritemSpacing) let totalSpacingWidth = cellSpacing * (cellCount - 1) let leftInset = (collectionView.frame.width - CGFloat(totalCellWidth + totalSpacingWidth)) / 2 let rightInset = leftInset return UIEdgeInsetsMake(0,leftInset,rightInset) } return collectionView.layoutMargins } 我收到以下控制台错误,但我的单元格小于我的collectionView,并且我将section insets和layout margin设置为0.
协议 class OverviewViewController: UIViewController,UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout { @IBOutlet weak var vipCollectionView: UICollectionView! var hostedMeetingsArray: [String]? var vipArray: [Attendee]? class OverviewViewController: UIViewController,UICollectionViewDelegateFlowLayout { @IBOutlet weak var vipCollectionView: UICollectionView! var hostedMeetingsArray: [String]? var vipArray: [Attendee]? 解决方法
好吧,没有调用insetForSectionAt的问题是你必须像这样实现它:
func collectionView(_ collectionView: UICollectionView,layout collectionViewLayout: UICollectionViewLayout,insetForSectionAt section: Int) -> UIEdgeInsets { //access to minimumInteritemSpacing by casting to UICollectionViewFlowLayout let layout = collectionViewLayout as! UICollectionViewFlowLayout let spacing = layout.minimumInteritemSpacing return UIEdgeInsetsMake(0.5,0.5,0) } 看看UICollectionViewDelegateFlowLayout协议. insetForSectionAt声明如下: @available(iOS 6.0,*) optional public func collectionView(_ collectionView: UICollectionView,insetForSectionAt section: Int) -> UIEdgeInsets 所以你需要第一个可选参数来实现这个功能. (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |