更新UICollectionView中的标签
Posted
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了更新UICollectionView中的标签相关的知识,希望对你有一定的参考价值。
我使用UICollectionView创建了这个当我单击Add(+)
或Remove(-)
按钮然后我想更新标签。我怎样才能做到这一点?
MainViewController.swift
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if(collectionView == ProductCollectionView){
let Productcell = self.ProductCollectionView.dequeueReusableCell(withReuseIdentifier:"ProductCollectionViewCell", for: indexPath) as! ProductCollectionViewCell
Productcell.AddOrMinusLabel.text = "(bestOfferProductCount[indexPath.row])"
Productcell.ProdName.text = bestOfferProductName[indexPath.row]
Productcell.ProdPrice.text = bestOfferProductPrice[indexPath.row]
Productcell.ProdtOrgPrice.text = bestOfferProductOriginalPrice[indexPath.row]
Productcell.ProdWeight.text = bestOfferProductWeight[indexPath.row]+" "+bestOfferProductUnit[indexPath.row]
Productcell.ProductImage.setImageFromURl(stringImageUrl: bestOfferProductImage[indexPath.row])
return Productcell
}
}
ProductCollectionViewCell.swift
import UIKit
class ProductCollectionViewCell: UICollectionViewCell {
@IBOutlet weak var ProdPrice: UILabel!
@IBOutlet weak var ProdtOrgPrice: UILabel!
@IBOutlet weak var ProductImage: UIImageView!
@IBOutlet weak var ProdName: UILabel!
@IBOutlet weak var ProdWeight: UILabel!
}
我会使用协议,将其添加到您的单元格类并将IBAction添加到UIButton。
class ProductCollectionViewCell: UICollectionViewCell {
@IBOutlet weak var ProdPrice: UILabel!
@IBOutlet weak var ProdtOrgPrice: UILabel!
@IBOutlet weak var ProductImage: UIImageView!
@IBOutlet weak var ProdName: UILabel!
@IBOutlet weak var ProdWeight: UILabel!
weak open var delegate: ProductCollectionViewCellDelegate?
@IBAction func btnIncrement(_ sender: UIButton)
{
if let d = self.delegate {
d.didTapOnIncrement(cell: self)
}
}
@IBAction func btnDecrement(_ sender: UIButton)
{
if let d = self.delegate {
d.didTapOnDecrement(cell: self)
}
}
}
protocol ProductCollectionViewCellDelegate: NSObjectProtocol {
func didTapOnIncrement(cell: ProductCollectionViewCell)
func didTapOnDecrement(cell: ProductCollectionViewCell)
}
现在在你的cellForItemAt方法中,添加这一行 -
cell.delegate = self
现在确认代理确认协议。在这个例子中,我想它是你的viewController。
extension ViewController: ProductCollectionViewCellDelegate {
func didTapOnIncrement(cell: ProductCollectionViewCell) {
//let indexPath = self.tableView.indexPath(for: cell)
//You have the cell's instance here. You can also get the indexPath by delegate method.
//You can add the increment-decrement logic here.
}
func didTapOnDecrement(cell: ProductCollectionViewCell) {
//let indexPath = self.tableView.indexPath(for: cell)
//You have the cell's instance here. You can also get the indexPath by delegate method.
//You can add the increment-decrement logic here.
}
}
我说,总是在单元格类中配置您的单元格数据
import UIKit
class ProductCollectionViewCell: UICollectionViewCell {
@IBOutlet weak var addOrMinusLabel: UILabel!
@IBOutlet weak var ProdPrice: UILabel!
@IBOutlet weak var ProdtOrgPrice: UILabel!
@IBOutlet weak var ProductImage: UIImageView!
@IBOutlet weak var ProdName: UILabel!
@IBOutlet weak var ProdWeight: UILabel!
var count = 1 {
didSet{
self.addOrMinusLabel.text = "(count)"
}
}
func configureData(count: Int) {
self.count = count
}
@IBAction func subtract(_ sender: UIButton) {
self.count -= 1
}
@IBAction func add(_ sender: UIButton) {
self.count += 1
}
}
并在您的视图控制器中
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if(collectionView == ProductCollectionView){
let Productcell = self.ProductCollectionView.dequeueReusableCell(withReuseIdentifier:"ProductCollectionViewCell", for: indexPath) as! ProductCollectionViewCell
Productcell.configureData(count: (bestOfferProductCount[indexPath.row]))
// do try to configure these below labels also within cell class
Productcell.ProdName.text = bestOfferProductName[indexPath.row]
Productcell.ProdPrice.text = bestOfferProductPrice[indexPath.row]
Productcell.ProdtOrgPrice.text = bestOfferProductOriginalPrice[indexPath.row]
Productcell.ProdWeight.text = bestOfferProductWeight[indexPath.row]+" "+bestOfferProductUnit[indexPath.row]
Productcell.ProductImage.setImageFromURl(stringImageUrl: bestOfferProductImage[indexPath.row])
return Productcell
}
}
有多种方法可以解决这个问题。
1.旧代表机制
当你将一个Cell出列时,你必须删除AllObservers,然后从单元格中将AddTarget移动到你的ViewController,以获得带有发送者的加号和减号的tap事件。在你的callee方法中,你必须获取它的superView(直到你到达collectionViewCell视图),然后从UICollectoinView询问该单元格的itemIndex,并相应地更新你的视图和单元格和模型。
2.使用闭包
您可以在Cell中定义两个闭包,一个用于加号,一个用于减去,而不是将Target添加到viewController,向您的单元格添加目标并调用相应的闭包,每次尝试返回一个Cell时,设置这些闭包并执行相应地。
class CustomCell: UICollectionCell {
var plusAction: (() -> Void)?
var minusAction: (() -> Void)?
@IBOutlet var counterLabel: UILabel!
@IBAction plusTapped() {
plusAction?()
}
@IBAction minusTapped() {
minusAction?()
}
}
在你的cellDequeue方法中:
cellForItemAtIndexPath(/*...other parameters...*/) -> UICollectionCell {
let cell = collectionView.dequeueCell(/*...other parameters...*/) as! CustomCell
// other customizations
// weak allocation in closure might not be needed here since closure reference is nullable on the other end, but i wrote it just in-case.
cell.plusAction = { [weak weakCell = cell] in
let counter = 0 // i said 0 for ex, You actually have to have them stored somewhere (even initial zeros) and fetch the actual value for this indexPath
let newCounter = counter + 1
// update your Model with newCounter
weakCell?.counterLabel.text = "(newCounter)"
}
cell.minusAction = { [weak weakCell = cell] in
let counter = 0 // i said 0 for ex, You actually have to have them stored somewhere (even initial zeros) and fetch the actual value for this indexPath
let newCounter = counter - 1
// update your Model with newCounter
weakCell?.counterLabel.text = "(newCounter)"
}
}
试试这个简单的清醒
在viewcontroller
中添加此代码
@IBAction func onBtnPlusClick(_ sender : UIButton) {
if let cell = sender.superview?.superview as? ProductCollectionViewCell {
let indexPath = yourCollectionViewOutlet.indexPath(for: cell)
//Do whatever you want or update your data model values
yourCollectionViewOutlet.reloadData()
}
}
@IBAction func onBtnMinusClick(_ sender : UIButton) {
if let cell = sender.superview?.superview as? ProductCollectionViewCell {
let indexPath = yourCollectionViewOutlet.indexPath(for: cell)
//Do whatever you want or update your data model values
yourCollectionViewOutlet.reloadData()
}
}
在你的cellForItemAt
中添加目标到按钮
btnPlus.addTarget(self, action: #selector(self. onBtnPlusClick(_:)), for: .touchUpInside)
btnMinus.addTarget(self, action: #selector(self. onBtnPlusClick(_:)), for: .touchUpInside)
在ProductCollectionViewCell
类中添加两个按钮插座
@IBOutlet var btnPlus : UIButton!
@IBOutlet var btnMinus : UIButton!
就是这样,希望这有帮助
以上是关于更新UICollectionView中的标签的主要内容,如果未能解决你的问题,请参考以下文章
如何根据 UICollectionView 的部分以编程方式更新标签
Swift UICollectionView 在单击时更新单元格标签而不是实时更新
Swift - UICollectionView:如何在标题中自动布局标签间距
UICollectionView reloadData() 不会更新集合视图中的单元格