如何在UICollectionViewDelegateFlowLayout中设置无间距?

Question

我正在尝试做一个UICollectionViewDelegateFlowLayout，其中有3个项目，在屏幕宽度的三分之一处排一行。由于某种原因，它增加了间距并且不符合方形布局。

下面是 UICollectionViewDelegateFlowLayout 函数。

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let yourWidth = (collectionView.bounds.width/3.0) - 2
let yourHeight = yourWidth

return CGSize(width: yourWidth, height: yourHeight)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
//return UIEdgeInsets.zero
return UIEdgeInsets(top: 0,left: 0,bottom: 0,right: 0);
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 1
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 1
}

请不要建议在 viewDidLoad 方法中向集合视图添加布局。我试过了，但它不起作用，因为它删除了我的标题。

Answer 1

class VC : UICollectionViewDelegateFlowLayout, UICollectionViewDelegate {

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let yourWidth = (collectionView.frame.width - 4)/3
// your minimumInteritemSpacing is 1, hence 4
let yourHeight = yourWidth
return CGSize(width: yourWidth, height: yourHeight)
}

}

您也可以尝试：

override func viewDidLoad() {
super.viewDidLoad()
let layout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout
layout?.estimatedItemSize = .init()
layout?.headerReferenceSize = .init()
}

Answer 2

您可以尝试使用以下代码：

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let marginsAndInsets = inset * 2 + collectionView.safeAreaInsets.left + collectionView.safeAreaInsets.right + minimumInteritemSpacing * CGFloat(cellsPerRow - 1)
//set inset, minimumInteritemSpacing and cellsPerRow globally
let itemSize = ((collectionView.bounds.size.width - marginsAndInsets) / CGFloat(cellsPerRow)).rounded(.down)
return CGSize(width: itemSize, height: itemSize)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
//return UIEdgeInsets.zero
return UIEdgeInsets(top: 0,left: 0,bottom: 0,right: 0);
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 1
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 1
}