第18月第10天 iOS11 uicollectionview

1.

- (void)collectionView:(UICollectionView *)collectionView willDisplaySupplementaryView:(UICollectionReusableView *)view forElementKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath {
    view.layer.zPosition = 0.0;
}

https://stackoverflow.com/questions/45871149/ios-11-uicollectionview-when-appearing-scrolling-happens