如何设置单元格间距和 UICollectionView - UICollectionViewFlowLayout 大小比例？

Question

我正在尝试将 UICollectionView 添加到 ViewController，我需要有 3 个单元格 'per row'，单元格之间没有空白 space（它应该看起来像网格）。单元格宽度应为屏幕尺寸的三分之一，所以我认为 layout.item 宽度应该相同。但后来我明白了：

如果我减小该尺寸（例如 7 或 8 像素 ），效果会更好，但行中的第三个单元格不是完全可见，我仍然有空白 space（顶部和底部，左侧和右侧）。

class ViewController: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
    var collectionView: UICollectionView?
    var screenSize: CGRect!
    var screenWidth: CGFloat!
    var screenHeight: CGFloat!

    override func viewDidLoad() {
        super.viewDidLoad()

        screenSize = UIScreen.mainScreen().bounds
        screenWidth = screenSize.width
        screenHeight = screenSize.height

        // Do any additional setup after loading the view, typically from a nib
        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 20, left: 0, bottom: 10, right: 0)
        layout.itemSize = CGSize(width: screenWidth / 3, height: screenWidth / 3)
        collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        collectionView!.dataSource = self
        collectionView!.delegate = self
        collectionView!.registerClass(CollectionViewCell.self, forCellWithReuseIdentifier: "CollectionViewCell")
        collectionView!.backgroundColor = UIColor.greenColor()
        self.view.addSubview(collectionView!)
    }

    func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return 1
    }

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 20
    }

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell", forIndexPath: indexPath) as CollectionViewCell
        cell.backgroundColor = UIColor.whiteColor()
        cell.layer.borderColor = UIColor.blackColor().CGColor
        cell.layer.borderWidth = 0.5
        cell.frame.size.width = screenWidth / 3
        cell.frame.size.height = screenWidth / 3

        cell.textLabel?.text = "\(indexPath.section):\(indexPath.row)"
        return cell
    }
}

Answer 1

添加这两行

layout.minimumInteritemSpacing = 0
layout.minimumLineSpacing = 0

所以你有：

   // Do any additional setup after loading the view, typically from a nib.
        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 20, left: 0, bottom: 10, right: 0)
        layout.itemSize = CGSize(width: screenWidth/3, height: screenWidth/3)
        layout.minimumInteritemSpacing = 0
        layout.minimumLineSpacing = 0
        collectionView!.collectionViewLayout = layout

这将删除所有空格并为您提供网格布局：

如果您希望第一列的宽度等于屏幕宽度，请添加以下函数：

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
    if indexPath.row == 0
    {
        return CGSize(width: screenWidth, height: screenWidth/3)
    }
    return CGSize(width: screenWidth/3, height: screenWidth/3);

}

网格布局现在看起来像（我还为第一个单元格添加了蓝色背景）：

Answer 2

对于 Swift 3 和 XCode 8，这有效。请按照以下步骤实现此目的：-

{
    let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
    let width = UIScreen.main.bounds.width
    layout.sectionInset = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
    layout.itemSize = CGSize(width: width / 2, height: width / 2)
    layout.minimumInteritemSpacing = 0
    layout.minimumLineSpacing = 0
    collectionView!.collectionViewLayout = layout
}

将此代码放入 viewDidLoad() 函数中。

Answer 3

对于 Swift 3 和 XCode 8， 这有效。请按照以下步骤实现此目的：-

viewDidLoad()
    {
        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        var width = UIScreen.main.bounds.width
        layout.sectionInset = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
    width = width - 10
    layout.itemSize = CGSize(width: width / 2, height: width / 2)
        layout.minimumInteritemSpacing = 0
        layout.minimumLineSpacing = 0
        collectionView!.collectionViewLayout = layout
    }

Answer 4

如果您正在寻找Swift 3，请按照以下步骤实现：

func viewDidLoad() {

    //Define Layout here
    let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()

    //Get device width
    let width = UIScreen.main.bounds.width

    //set section inset as per your requirement.
    layout.sectionInset = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)

    //set cell item size here 
    layout.itemSize = CGSize(width: width / 2, height: width / 2)

    //set Minimum spacing between 2 items
    layout.minimumInteritemSpacing = 0

    //set minimum vertical line spacing here between two lines in collectionview
    layout.minimumLineSpacing = 0

    //apply defined layout to collectionview
    collectionView!.collectionViewLayout = layout

}

这已在 Xcode 8.0 和 Swift 3.

上得到验证

Answer 5

在某些情况下，在 viewDidLoad 或 ViewWillAppear 中设置 UICollectionViewFlowLayout 可能不会影响 collectionView。

在viewDidAppear中设置UICollectionViewFlowLayout可能会导致在运行时看到单元格大小的变化。

另一个解决方案，在 Swift 3 :

extension YourViewController : UICollectionViewDelegateFlowLayout{

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: 20, left: 0, bottom: 10, right: 0)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let collectionViewWidth = collectionView.bounds.width
        return CGSize(width: collectionViewWidth/3, height: collectionViewWidth/3)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 20
    }
}

Answer 6

let layout = myCollectionView.collectionViewLayout as? UICollectionViewFlowLayout
layout?.minimumLineSpacing = 8

Answer 7

Swift 4

let collectionViewLayout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout
collectionViewLayout?.sectionInset = UIEdgeInsetsMake(0, 20, 0, 40) 
collectionViewLayout?.invalidateLayout()

Answer 8

对于 Swift 3+ 和 Xcode 9+ 尝试使用此

extension ViewController: UICollectionViewDelegateFlowLayout {

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

    let collectionWidth = collectionView.bounds.width
    return CGSize(width: collectionWidth/3, height: collectionWidth/3)

}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return 0
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return 0

}

Answer 9

Swift 5 : 对于具有动态单元格宽度的单元格之间均匀分布 spaces 以充分利用容器 space 你可以通过提供 minimumCellWidth 值使用下面的代码片段。

private func collectionViewLayout() -> UICollectionViewLayout {
    
    let layout = UICollectionViewFlowLayout()
    layout.sectionHeadersPinToVisibleBounds = true
    // Important: if direction is horizontal use minimumItemSpacing instead. 
    layout.scrollDirection = .vertical
    
    let itemHeight: CGFloat = 240
    let minCellWidth :CGFloat = 130.0
    let minItemSpacing: CGFloat = 10
    let containerWidth: CGFloat = self.view.bounds.width
    let maxCellCountPerRow: CGFloat =  floor((containerWidth - minItemSpacing) / (minCellWidth+minItemSpacing ))
    
    let itemWidth: CGFloat = floor( ((containerWidth - (2 * minItemSpacing) - (maxCellCountPerRow-1) * minItemSpacing) / maxCellCountPerRow  ) )
    // Calculate the remaining space after substracting calculating cellWidth (Divide by 2 because of left and right insets)
    let inset = max(minItemSpacing, floor( (containerWidth - (maxCellCountPerRow*itemWidth) - (maxCellCountPerRow-1)*minItemSpacing) / 2 ) )

    
    layout.itemSize = CGSize(width: itemWidth, height: itemHeight)
    layout.minimumInteritemSpacing = min(minItemSpacing,inset)
    layout.minimumLineSpacing = minItemSpacing
    layout.sectionInset = UIEdgeInsets(top: minItemSpacing, left: inset, bottom: minItemSpacing, right: inset)

    
    return layout
}

Answer 10

Swift 4，Swift 5，最简单的方法！

无需创建 UICollectionViewFlowLayout() 实例，只需在您的 Class.

上实施 UICollectionViewDelegateFlowLayout

extension MyCollectionView: UICollectionViewDelegateFlowLayout {

    // Distance Between Item Cells
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 20
    }
    
    // Cell Margin
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: 16, left: 16, bottom: 16, right: 16)
    }

}

Answer 11

不用写一行代码，我们在 XCode、select CollectionView 中有一个选项，然后转到导航器并更改 "Min Spacing "

如何设置单元格间距和 UICollectionView - UICollectionViewFlowLayout 大小比例？

How to set cell spacing and UICollectionView - UICollectionViewFlowLayout size ratio?

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