UICollectionView设置列数
SNV*_*NV7 91 xcode objective-c ios uicollectionview uicollectionviewcell
我刚开始学习UICollectionViews.我想知道是否有人知道如何指定集合视图中的列数.默认设置为3(iPhone /肖像).我查看了文档,似乎无法找到简明的答案.
Ima*_*tit 121
使用Swift 4.1和iOS 11,您可以使用以下4个实现中的一个来设置UICollectionView管理插图和大小更改(包括旋转)时每行的项数.
#1.子类化UICollectionViewFlowLayout和使用UICollectionViewFlowLayout的itemSize属性
ColumnFlowLayout.swift:
import UIKit
class ColumnFlowLayout: UICollectionViewFlowLayout {
let cellsPerRow: Int
init(cellsPerRow: Int, minimumInteritemSpacing: CGFloat = 0, minimumLineSpacing: CGFloat = 0, sectionInset: UIEdgeInsets = .zero) {
self.cellsPerRow = cellsPerRow
super.init()
self.minimumInteritemSpacing = minimumInteritemSpacing
self.minimumLineSpacing = minimumLineSpacing
self.sectionInset = sectionInset
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func prepare() {
super.prepare()
guard let collectionView = collectionView else { return }
let marginsAndInsets = sectionInset.left + sectionInset.right + collectionView.safeAreaInsets.left + collectionView.safeAreaInsets.right + minimumInteritemSpacing * CGFloat(cellsPerRow - 1)
let itemWidth = ((collectionView.bounds.size.width - marginsAndInsets) / CGFloat(cellsPerRow)).rounded(.down)
itemSize = CGSize(width: itemWidth, height: itemWidth)
}
override func invalidationContext(forBoundsChange newBounds: CGRect) -> UICollectionViewLayoutInvalidationContext {
let context = super.invalidationContext(forBoundsChange: newBounds) as! UICollectionViewFlowLayoutInvalidationContext
context.invalidateFlowLayoutDelegateMetrics = newBounds.size != collectionView?.bounds.size
return context
}
}
CollectionViewController.swift:
import UIKit
class CollectionViewController: UICollectionViewController {
let columnLayout = ColumnFlowLayout(
cellsPerRow: 5,
minimumInteritemSpacing: 10,
minimumLineSpacing: 10,
sectionInset: UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
)
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.collectionViewLayout = columnLayout
collectionView?.contentInsetAdjustmentBehavior = .always
collectionView?.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 59
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
cell.backgroundColor = UIColor.orange
return cell
}
}
#2.使用UICollectionViewFlowLayout的itemSize方法
import UIKit
class CollectionViewController: UICollectionViewController {
let margin: CGFloat = 10
let cellsPerRow = 5
override func viewDidLoad() {
super.viewDidLoad()
guard let collectionView = collectionView, let flowLayout = collectionViewLayout as? UICollectionViewFlowLayout else { return }
flowLayout.minimumInteritemSpacing = margin
flowLayout.minimumLineSpacing = margin
flowLayout.sectionInset = UIEdgeInsets(top: margin, left: margin, bottom: margin, right: margin)
collectionView.contentInsetAdjustmentBehavior = .always
collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
}
override func viewWillLayoutSubviews() {
guard let collectionView = collectionView, let flowLayout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout else { return }
let marginsAndInsets = flowLayout.sectionInset.left + flowLayout.sectionInset.right + collectionView.safeAreaInsets.left + collectionView.safeAreaInsets.right + flowLayout.minimumInteritemSpacing * CGFloat(cellsPerRow - 1)
let itemWidth = ((collectionView.bounds.size.width - marginsAndInsets) / CGFloat(cellsPerRow)).rounded(.down)
flowLayout.itemSize = CGSize(width: itemWidth, height: itemWidth)
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 59
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
cell.backgroundColor = UIColor.orange
return cell
}
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
collectionView?.collectionViewLayout.invalidateLayout()
super.viewWillTransition(to: size, with: coordinator)
}
}
#3.使用UICollectionViewDelegateFlowLayout的collectionView(_:layout:sizeForItemAt:)方法
import UIKit
class CollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
let inset: CGFloat = 10
let minimumLineSpacing: CGFloat = 10
let minimumInteritemSpacing: CGFloat = 10
let cellsPerRow = 5
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.contentInsetAdjustmentBehavior = .always
collectionView?.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: inset, left: inset, bottom: inset, right: inset)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return minimumLineSpacing
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return minimumInteritemSpacing
}
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)
let itemWidth = ((collectionView.bounds.size.width - marginsAndInsets) / CGFloat(cellsPerRow)).rounded(.down)
return CGSize(width: itemWidth, height: itemWidth)
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 59
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
cell.backgroundColor = UIColor.orange
return cell
}
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
collectionView?.collectionViewLayout.invalidateLayout()
super.viewWillTransition(to: size, with: coordinator)
}
}
#4.子类化UICollectionViewFlowLayout和使用UICollectionViewFlowLayout的estimatedItemSize属性
CollectionViewController.swift:
import UIKit
class CollectionViewController: UICollectionViewController {
let items = [
"Lorem ipsum dolor sit amet, consectetur adipiscing elit.",
"Lorem ipsum dolor sit amet, consectetur.",
"Lorem ipsum dolor sit amet.",
"Lorem ipsum dolor sit amet, consectetur.",
"Lorem ipsum dolor sit amet, consectetur adipiscing.",
"Lorem ipsum.",
"Lorem ipsum dolor sit amet.",
"Lorem ipsum dolor sit.",
"Lorem ipsum dolor sit amet, consectetur adipiscing.",
"Lorem ipsum dolor sit amet, consectetur adipiscing elit.",
"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.",
"Lorem ipsum dolor sit amet, consectetur."
]
let columnLayout = FlowLayout(
cellsPerRow: 3,
minimumInteritemSpacing: 10,
minimumLineSpacing: 10,
sectionInset: UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
)
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.collectionViewLayout = columnLayout
collectionView?.contentInsetAdjustmentBehavior = .always
collectionView?.register(Cell.self, forCellWithReuseIdentifier: "Cell")
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return items.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! Cell
cell.label.text = items[indexPath.row]
return cell
}
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
collectionView?.collectionViewLayout.invalidateLayout()
super.viewWillTransition(to: size, with: coordinator)
}
}
FlowLayout.swift:
import UIKit
class FlowLayout: UICollectionViewFlowLayout {
let cellsPerRow: Int
required init(cellsPerRow: Int = 1, minimumInteritemSpacing: CGFloat = 0, minimumLineSpacing: CGFloat = 0, sectionInset: UIEdgeInsets = .zero) {
self.cellsPerRow = cellsPerRow
super.init()
self.minimumInteritemSpacing = minimumInteritemSpacing
self.minimumLineSpacing = minimumLineSpacing
self.sectionInset = sectionInset
estimatedItemSize = UICollectionViewFlowLayout.automaticSize
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
guard let layoutAttributes = super.layoutAttributesForItem(at: indexPath) else { return nil }
guard let collectionView = collectionView else { return layoutAttributes }
let marginsAndInsets = collectionView.safeAreaInsets.left + collectionView.safeAreaInsets.right + sectionInset.left + sectionInset.right + minimumInteritemSpacing * CGFloat(cellsPerRow - 1)
layoutAttributes.bounds.size.width = ((collectionView.bounds.width - marginsAndInsets) / CGFloat(cellsPerRow)).rounded(.down)
return layoutAttributes
}
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
let superLayoutAttributes = super.layoutAttributesForElements(in: rect)!.map { $0.copy() as! UICollectionViewLayoutAttributes }
guard scrollDirection == .vertical else { return superLayoutAttributes }
let layoutAttributes = superLayoutAttributes.compactMap { layoutAttribute in
return layoutAttribute.representedElementCategory == .cell ? layoutAttributesForItem(at: layoutAttribute.indexPath) : layoutAttribute
}
// (optional) Uncomment to top align cells that are on the same line
/*
let cellAttributes = layoutAttributes.filter({ $0.representedElementCategory == .cell })
for (_, attributes) in Dictionary(grouping: cellAttributes, by: { ($0.center.y / 10).rounded(.up) * 10 }) {
guard let max = attributes.max(by: { $0.size.height < $1.size.height }) else { continue }
for attribute in attributes where attribute.size.height != max.size.height {
attribute.frame.origin.y = max.frame.origin.y
}
}
*/
// (optional) Uncomment to bottom align cells that are on the same line
/*
let cellAttributes = layoutAttributes.filter({ $0.representedElementCategory == .cell })
for (_, attributes) in Dictionary(grouping: cellAttributes, by: { ($0.center.y / 10).rounded(.up) * 10 }) {
guard let max = attributes.max(by: { $0.size.height < $1.size.height }) else { continue }
for attribute in attributes where attribute.size.height != max.size.height {
attribute.frame.origin.y += max.frame.maxY - attribute.frame.maxY
}
}
*/
return layoutAttributes
}
}
Cell.swift:
import UIKit
class Cell: UICollectionViewCell {
let label = UILabel()
override init(frame: CGRect) {
super.init(frame: frame)
label.numberOfLines = 0
backgroundColor = .orange
contentView.addSubview(label)
label.translatesAutoresizingMaskIntoConstraints = false
label.topAnchor.constraint(equalTo: contentView.layoutMarginsGuide.topAnchor).isActive = true
label.leadingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.leadingAnchor).isActive = true
label.trailingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.trailingAnchor).isActive = true
label.bottomAnchor.constraint(equalTo: contentView.layoutMarginsGuide.bottomAnchor).isActive = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
layoutIfNeeded()
label.preferredMaxLayoutWidth = label.bounds.size.width
layoutAttributes.bounds.size.height = contentView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize).height
return layoutAttributes
}
// Alternative implementation
/*
override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
label.preferredMaxLayoutWidth = layoutAttributes.size.width - contentView.layoutMargins.left - contentView.layoutMargins.right
layoutAttributes.bounds.size.height = contentView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize).height
return layoutAttributes
}
*/
}
- 使用“ viewWillTransition（to size ...”）的解决方案无法正确处理设备旋转。由于是在设置框架之前调用的，因此collectionView的旧尺寸用于计算像元大小。（尚未尝试其他解决方案呢） (2认同)
- 我使用了解决方案#1,你是我的新英雄. (2认同)
- 我使用了您的解决方案#1。它的精湛。 (2认同)
- 用清晰的例子给出了精彩的答案。我也很欣赏它如何为您指出不同的选择。它值得更多的赞成。 (2认同)
jhi*_*t00 79
CollectionViews非常强大,而且价格合理.很多,有很多选择.正如omz所说:
您可以通过多种方式更改列数
我建议实现<UICollectionViewDelegateFlowLayout>协议,让您可以访问以下方法,在这些方法中您可以更好地控制您的布局UICollectionView,而无需对其进行子类化:
collectionView:layout:insetForSectionAtIndex:collectionView:layout:minimumInteritemSpacingForSectionAtIndex:collectionView:layout:minimumLineSpacingForSectionAtIndex:collectionView:layout:referenceSizeForFooterInSection:collectionView:layout:referenceSizeForHeaderInSection:collectionView:layout:sizeForItemAtIndexPath:
此外,实现以下方法将强制您的UICollectionView在方向更改时更新它的布局:(假设您要为景观重新调整单元格的大小并使其延伸)
-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
duration:(NSTimeInterval)duration{
[self.myCollectionView.collectionViewLayout invalidateLayout];
}
另外,这里有2个非常好的教程UICollectionViews:
http://www.raywenderlich.com/22324/beginning-uicollectionview-in-ios-6-part-12
http://skeuo.com/uicollectionview-custom-layout-tutorial
noo*_*oob 61
我UICollectionViewDelegateFlowLayout在我的实现上UICollectionViewController覆盖了负责确定Cell大小的方法.然后我拿出屏幕宽度并按照我的列要求进行划分.例如,我想在每个屏幕尺寸上有3列.所以这就是我的代码 -
- (CGSize)collectionView:(UICollectionView *)collectionView
layout:(UICollectionViewLayout *)collectionViewLayout
sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
CGRect screenRect = [[UIScreen mainScreen] bounds];
CGFloat screenWidth = screenRect.size.width;
float cellWidth = screenWidth / 3.0; //Replace the divisor with the column count requirement. Make sure to have it in float.
CGSize size = CGSizeMake(cellWidth, cellWidth);
return size;
}
- 简单得多，感谢您的理智和更少的代码 (2认同)
- 您应确保将项目间距设置为0,以避免每行具有n-1个高度间隔的项目. (2认同)
sgi*_*gib 39
扩大noob的答案:
func collectionView(collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
let flowLayout = collectionViewLayout as! UICollectionViewFlowLayout
let totalSpace = flowLayout.sectionInset.left
+ flowLayout.sectionInset.right
+ (flowLayout.minimumInteritemSpacing * CGFloat(numberOfItemsPerRow - 1))
let size = Int((collectionView.bounds.width - totalSpace) / CGFloat(numberOfItemsPerRow))
return CGSize(width: size, height: size)
}
这允许细胞之间的任何间隔.它假设一个Int成员变量被调用numberOfItemsPerRow,并且所有单元格都是正方形且大小相同.正如jhilgert00的回答所述,我们还必须对方向变化作出反应,但现在使用viewWillTransitionToSizeas willRotateToInterfaceOrientation折旧.
fra*_*ool 12
这是Swift 3的工作代码,具有两列布局:
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
let nbCol = 2
let flowLayout = collectionViewLayout as! UICollectionViewFlowLayout
let totalSpace = flowLayout.sectionInset.left
+ flowLayout.sectionInset.right
+ (flowLayout.minimumInteritemSpacing * CGFloat(nbCol - 1))
let size = Int((collectionView.bounds.width - totalSpace) / CGFloat(nbCol))
return CGSize(width: size, height: size)
}
您可以随意将"nbCol"更改为所需的列数.
San*_*rya 10
更新至 Swift 5+ iOS 13
集合视图估计大小必须为无
声明单元格的边距
let margin: CGFloat = 10
在 viewDidLoad 配置minimumInteritemSpacing, minimumLineSpacing,sectionInset
guard let collectionView = docsColl, let flowLayout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout else { return }
flowLayout.minimumInteritemSpacing = margin
flowLayout.minimumLineSpacing = margin
flowLayout.sectionInset = UIEdgeInsets(top: margin, left: margin, bottom: margin, right: margin)
UICollectionViewDataSource方法sizeForItemAt
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let noOfCellsInRow = 2 //number of column you want
let flowLayout = collectionViewLayout as! UICollectionViewFlowLayout
let totalSpace = flowLayout.sectionInset.left
+ flowLayout.sectionInset.right
+ (flowLayout.minimumInteritemSpacing * CGFloat(noOfCellsInRow - 1))
let size = Int((collectionView.bounds.width - totalSpace) / CGFloat(noOfCellsInRow))
return CGSize(width: size, height: size)
}
更新到Swift 3:
我更喜欢使用特定列号和行号的自定义布局,而不是流布局.因为:
- 如果列数非常大,可以水平拖动它.
- 由于使用了列和行,因此在逻辑上更容易接受.
正常单元格和标题单元格:(将UILabel作为IBOutlet添加到xib中):
class CollectionViewCell: UICollectionViewCell {
@IBOutlet weak var label: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
self.backgroundColor = UIColor.black
label.textColor = UIColor.white
}
}
class CollectionViewHeadCell: UICollectionViewCell {
@IBOutlet weak var label: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
self.backgroundColor = UIColor.darkGray
label.textColor = UIColor.white
}
}
自定义布局:
let cellHeight: CGFloat = 100
let cellWidth: CGFloat = 100
class CustomCollectionViewLayout: UICollectionViewLayout {
private var numberOfColumns: Int!
private var numberOfRows: Int!
// It is two dimension array of itemAttributes
private var itemAttributes = [[UICollectionViewLayoutAttributes]]()
// It is one dimension of itemAttributes
private var cache = [UICollectionViewLayoutAttributes]()
override func prepare() {
if self.cache.isEmpty {
self.numberOfColumns = self.collectionView?.numberOfItems(inSection: 0)
self.numberOfRows = self.collectionView?.numberOfSections
// Dynamically change cellWidth if total cell width is smaller than whole bounds
/* if (self.collectionView?.bounds.size.width)!/CGFloat(self.numberOfColumns) > cellWidth {
self.cellWidth = (self.collectionView?.bounds.size.width)!/CGFloat(self.numberOfColumns)
}
*/
for row in 0..<self.numberOfRows {
var row_temp = [UICollectionViewLayoutAttributes]()
for column in 0..<self.numberOfColumns {
let indexPath = NSIndexPath(item: column, section: row)
let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath as IndexPath)
attributes.frame = CGRect(x: cellWidth*CGFloat(column), y: cellHeight*CGFloat(row), width: cellWidth, height: cellHeight)
row_temp.append(attributes)
self.cache.append(attributes)
}
self.itemAttributes.append(row_temp)
}
}
}
override var collectionViewContentSize: CGSize {
return CGSize(width: CGFloat(self.numberOfColumns)*cellWidth, height: CGFloat(self.numberOfRows)*cellHeight)
}
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
var layoutAttributes = [UICollectionViewLayoutAttributes]()
for attributes in cache {
if attributes.frame.intersects(rect) {
layoutAttributes.append(attributes)
}
}
return layoutAttributes
}
}
的CollectionView:
let CellIdentifier = "CellIdentifier"
let HeadCellIdentifier = "HeadCellIdentifier"
class CollectionView: UICollectionView, UICollectionViewDelegate, UICollectionViewDataSource {
init() {
let layout = CustomCollectionViewLayout()
super.init(frame: CGRect.zero, collectionViewLayout: layout)
self.register(UINib(nibName: "CollectionViewCell", bundle: nil), forCellWithReuseIdentifier: CellIdentifier)
self.register(UINib(nibName: "CollectionViewHeadCell", bundle: nil), forCellWithReuseIdentifier: HeadCellIdentifier)
self.isDirectionalLockEnabled = true
self.dataSource = self
self.delegate = self
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func updateCollectionView() {
DispatchQueue.main.async {
self.reloadData()
}
}
// MARK: CollectionView datasource
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 20
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 20
}
override func numberOfItems(inSection section: Int) -> Int {
return 20
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let column = (indexPath as NSIndexPath).row
let row = (indexPath as NSIndexPath).section
if column == 0 {
let cell : CollectionViewHeadCell = collectionView.dequeueReusableCell(withReuseIdentifier: HeadCellIdentifier, for: indexPath) as! CollectionViewHeadCell
cell.label.text = "\(row)"
return cell
}
else if row == 0 {
let cell : CollectionViewHeadCell = collectionView.dequeueReusableCell(withReuseIdentifier: HeadCellIdentifier, for: indexPath) as! CollectionViewHeadCell
cell.label.text = "\(column)"
return cell
}
else {
let cell : CollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: CellIdentifier, for: indexPath) as! CollectionViewCell
cell.label.text = String(format: "%d", arguments: [indexPath.section*indexPath.row])
return cell
}
}
// MARK: CollectionView delegate
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let column = (indexPath as NSIndexPath).row
let row = (indexPath as NSIndexPath).section
print("\(column) \(row)")
}
}
使用ViewController中的CollectionView:
class ViewController: UIViewController {
let collectionView = CollectionView()
override func viewDidLoad() {
collectionView.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(collectionView)
self.view.backgroundColor = UIColor.red
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[collectionView]|", options: [], metrics: nil, views: ["collectionView": collectionView]))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[collectionView]|", options: [], metrics: nil, views: ["collectionView": collectionView]))
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
collectionView.updateCollectionView()
}
}
最后你可以拥有精美的CollectionView!
- @rd_Custom布局意味着你可以做你想做的事!我的代码只显示最简单的情况...... (2认同)
由于UICollectionView非常灵活,您可以通过多种方式更改列数,具体取决于您使用的布局类型.
的UICollectionViewFlowLayout(这可能是你正在使用什么)不直接指定的列数(因为它取决于视图大小/方向).更改它的最简单方法是设置itemSize属性和/或minimumInteritemSpacing/ minimumLineSpacing.
如果你懒惰使用委托.
extension UICollectionView {
func setItemsInRow(items: Int) {
if let layout = self.collectionViewLayout as? UICollectionViewFlowLayout {
let contentInset = self.contentInset
let itemsInRow: CGFloat = CGFloat(items);
let innerSpace = layout.minimumInteritemSpacing * (itemsInRow - 1.0)
let insetSpace = contentInset.left + contentInset.right + layout.sectionInset.left + layout.sectionInset.right
let width = floor((CGRectGetWidth(frame) - insetSpace - innerSpace) / itemsInRow);
layout.itemSize = CGSizeMake(width, width)
}
}
}
PS:旋转后也应调用
- 它也适用于 Swift 4.0... 更改最后两行后： let width = floor((frame.width - insetSpace -innerSpace) / itemsInRow) layout.itemSize = CGSize(width: width, height: width) (2认同)
斯威夫特 3.0。适用于水平和垂直滚动方向和可变间距
指定列数
let numberOfColumns: CGFloat = 3
配置flowLayout渲染指定numberOfColumns
if let flowLayout = collectionView?.collectionViewLayout as? UICollectionViewFlowLayout {
let horizontalSpacing = flowLayout.scrollDirection == .vertical ? flowLayout.minimumInteritemSpacing : flowLayout.minimumLineSpacing
let cellWidth = (collectionView.frame.width - max(0, numberOfColumns - 1)*horizontalSpacing)/numberOfColumns
flowLayout.itemSize = CGSize(width: cellWidth, height: cellWidth)
}