ios - 如何使用swift 4显示像facebook上传图片这样的collectionView？

Question

您好，我想完全按照上图显示 collectionView。我知道它负责 UICollectionViewFlowLayout，但无法做到。非常感谢您的帮助。这是我的代码

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
     let yourWidth = (collectionView.bounds.width - 4) / 3.0
     let yourHeight = yourWidth
     return CGSize(width: yourWidth, height: yourHeight)
}

Answer 1

您的答案在您的问题中，兄弟缺少一些条件

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        switch indexPath.item {
        case 0,1:
            return CGSize(width: (UIScreen.main.bounds.width - 16) / 2, height: (UIScreen.main.bounds.width - 16) / 2)
        default:
            return CGSize(width: (UIScreen.main.bounds.width - 32) / 3, height:  (UIScreen.main.bounds.width) / 3)
        }
    }

Answer 2

如果这是您正在寻找的东西，那么它很容易做到UICollectionViewFlowLayout

我使用单元格的比例为 1:1，因此宽度和高度相同，您可以使用填充和项目间距等来获得所需的效果。

您的控制器必须符合UICollectionViewDelegateFlowLayout协议

在我的测试应用程序中，我执行了以下操作：

override func viewDidLoad() {
    let layout = UICollectionViewFlowLayout()
    layout.minimumLineSpacing = 5
    layout.minimumInteritemSpacing = 5
    let collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: layout)
    collectionView.delegate = self
    collectionView.dataSource = self
    collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "ident")

    view.addSubview(collectionView)
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let item = indexPath.item
    let width = collectionView.bounds.size.width
    let padding:CGFloat = 5
    if item < 2 {
        let itemWidth:CGFloat = (width - padding) / 2.0
        return CGSize(width: itemWidth, height: itemWidth)
    } else {
        let itemWidth:CGFloat = (width - 2 * padding) / 3.0
        return CGSize(width: itemWidth, height: itemWidth)
    }
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 5
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ident", for: indexPath)
    cell.backgroundColor = .red
    return cell
}