swift - 如何: Center UICollectionViewCells

Question

我有一个 Collection View 数据源正在经历 View 更新/并在此过程中多次重新加载其数据。有人可以告诉我如何在完成所有操作后将单元格居中吗？

数据源方法:

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return self.testSlice.count
    }

当前方法处理单元格样式并做一些其他事情:

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! MyCollectionViewCell

        cell.profilePicture.layer.masksToBounds = true

        print("DEV: testSlice value: \(testSlice)")
        print("DEV: limitedNames value: \(limitedNames)")

        if testSlice != [] {
            cell.profilePicture.playPortalProfilePic(forImageId: testSlice[indexPath.item], { error in
                if let error = error {
                    print("Error requesting profile pic: \(String(describing: error))")

                    if let index = self.testSlice.index(of: "") {
                        self.testSlice.remove(at: index)
                        collectionView.reloadData()


                    }

                }
            }
            )
        } else {
            print("items array was empty, value: \(items)")
        }



        cell.backgroundColor = UIColor.cyan
        cell.layer.borderColor = UIColor.black.cgColor
        cell.layer.borderWidth = 1
        cell.layer.cornerRadius = 8

        return cell
    }

我相信我正在寻找一个善于约束的人，​​除非可以通过其他方式做到这一点。

我正在尝试将显示的标签下的单元格居中

Answer 1

您可以通过调整该部分的插图来使单元格居中(如果您只有一个部分)

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {

    let widthOfCell = 50 // What ever the width of the cell is 
    let spacingBetweenCells = 10 

    let totalCellWidth = widthOfCell * self.data.count
    let totalSpacingWidth = spacingBetweenCells * (self.data.count - 1)

    let leftInset = (collectionView.frame.width - CGFloat(totalCellWidth + totalSpacingWidth)) / 2

    if leftInset < 0 {
        return UIEdgeInsets.zero
    }

    let rightInset = leftInset

    return UIEdgeInsets(top: 0, left: leftInset, bottom: 0, right: rightInset)
}