如何获取UICollectionView的头部视图的索引路径？

Question

如何获取UICollectionView的头部视图的索引路径？

iosuicollectionviewuicollectionviewlayout

6

使用视图的indexPathForItemAtPoint方法，可以获取单元格的索引路径，但永远不会返回UICollectionReusableView（头部/尾部视图），因为它总是返回nil。

- akaru

2个回答

1

你可以为UICollectionView添加扩展，其中传递补充视图的引用和该视图的类型（UICollectionView.elementKindSectionHeader或UICollectionView.elementKindSectionFooter）。

extension UICollectionView {
    
    func indexPathForSupplementaryElement(_ supplementaryView: UICollectionReusableView, ofKind kind: String) -> IndexPath? {
        let visibleIndexPaths = self.indexPathsForVisibleSupplementaryElements(ofKind: kind)
        return visibleIndexPaths.first(where: {
            self.supplementaryView(forElementKind: kind, at: $0) == supplementaryView
        })
    }
    
}

如果补充视图不可见，则此方法无效！

- Yurii Lysytsia

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- jovanpreet · Accepted Answer

override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    switch kind {
    case UICollectionElementKindSectionHeader:
        let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "header", for: indexPath) as! HeaderCollectionReusableView
        let gestureRecognizer: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(didSelectSection(gesture:)))
        headerView.addGestureRecognizer(gestureRecognizer)
        return headerView
    }
}

现在在didSelectSection中：

func didSelectSection(gesture: UITapGestureRecognizer) {
    let indexPaths = self.collectionView?.indexPathsForVisibleSupplementaryElements(ofKind: UICollectionElementKindSectionHeader)
    for indexPath in indexPaths! {
        if (gesture.view as! HeaderCollectionReusableView) == collectionView?.supplementaryView(forElementKind: UICollectionElementKindSectionHeader, at: indexPath){
            print("found at : \(indexPath)")
            break
        }
    }
}