swift：CollectionView单元格大小

Question

我有一个带有约束的collectionView到superview。 我想为iPhone X获得此结果：

但我明白了：

怎么解决？

码：

func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 4
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }

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


        cellOffset = 10

        cellWidth = (667 / 3)  - (cellOffset * 4)
        cellHeight =  (cellWidth / 2 * 3) + (cellWidth / 2 * 0.65)

        return CGSize(width: cellWidth, height: cellHeight)
    }

更新

更新

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

        let sectionInset = collectionView.frame.width / 3.0
        let margins = CGFloat(10.0 * 2.0)
        let width = (collectionView.frame.width - sectionInset - margins) / 3.0
        let height = collectionView.frame.height - 40.0

        let collectionViewLayout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout
        collectionViewLayout?.sectionInset = UIEdgeInsets(top: 0, left: 6.0, bottom: 0, right: 6.0)
        collectionViewLayout?.minimumInteritemSpacing = 10
        collectionViewLayout?.invalidateLayout()

        return CGSize(width: width, height: height)
    }

结果：

Answer 1

如果你想在景观中有3个细胞

let cellWidth = ( self.collectionView.frame.width - 2 * cellOffset ) / 3

Answer 2

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



    return CGSize(width: collectionView.frame.size.width/4 - 1, height: collectionView.frame.size.width/4 - 1)
}

Answer 3

我的建议是考虑重构您的布局，使每个部分左右嵌入您正在寻找的边距。 然后，您可以按以下方式描述单元格大小：

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let sectionInset = collectionView.frame.width / 3.0
    let margins = CGFloat(10.0 * 2.0)
    let width = (collectionView.frame.width - sectionInset - margins) / 3.0
    let height = collectionView.frame.height - 40.0

    return CGSize(width: width, height: height)
}

接下来，您需要在适当的委托方法中返回此部分的插入值。 假设您要保留此边距的集合视图的第一个和最后六个，这大致与图像相同。

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    return UIEdgeInsets(top: 0,
                        left: collectionView.frame.width / 6.0,
                        bottom: 0,
                        right: collectionView.frame.width / 6.0)
}

总而言之，我们最终得到了这个修订：

func numberOfSections(in collectionView: UICollectionView) -> Int {
    return 4
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 3
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let sectionInset = collectionView.frame.width / 3.0
    let margins = CGFloat(10.0 * 2.0)
    let width = (collectionView.frame.width - sectionInset - margins) / 3.0
    let height = collectionView.frame.height - 40.0

    return CGSize(width: width, height: height)
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return 10.0
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    return UIEdgeInsets(top: 0,
                        left: collectionView.frame.width / 6.0,
                        bottom: 0,
                        right: collectionView.frame.width / 6.0)
}

Answer 4

您需要通过此设置集合视图的布局。

// setup collection view
let numberItemPerRow = 4
let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
layout.sectionInset = UIEdgeInsets(top: 1, left: 0, bottom: 1, right: 0)
layout.itemSize = CGSize(width: ScreenSize.width/numberItemPerRow-1, 
                         height: ScreenSize.width/numberItemPerRow)
layout.minimumInteritemSpacing = 1
layout.minimumLineSpacing = 1
your_collection.collectionViewLayout = layout

我保证这段代码会被解决。 ！

Answer 5

你让它有点太复杂了。 它只是与插图和大小一起玩。 这是示例代码：

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    return UIEdgeInsetsMake(0, 145, 0, 145)
}

func numberOfSections(in collectionView: UICollectionView) -> Int {
    return 4
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 3
}

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

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    return CGSize(width: self.view.frame.width / 3 - 100 , height: collectionView.frame.size.height - 100)
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return 5
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return 5
}

这是它给出的图像：

更新

import UIKit

class ViewController: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource, UICollectionViewDelegate {

    lazy var collectionView : UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.backgroundColor = .green
        cv.isPagingEnabled = true
        cv.delegate = self
        cv.dataSource = self
        return cv
    }()


    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.addSubview(collectionView)
        collectionView.register(Cell.self, forCellWithReuseIdentifier: "cell")
        collectionView.frame = self.view.frame
        collectionView.contentInset = UIEdgeInsetsMake(0, -45, 0, -45)
    }


    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsetsMake(0, 145, 0, 145)
    }

    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 4
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }

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

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: self.view.frame.width / 3 - 100 , height: collectionView.frame.size.height - 100)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 5
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 5
    }

}

class Cell : UICollectionViewCell {


    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func setupViews() {
        self.backgroundColor = .red
    }

}