在我的 View Controller 中,我正在加载带有子类的自定义 CollectionViewCell。根据单元格索引路径的位置,我想以不同的方式设置文本标签的格式。 IE。第一行只有一个文本较大的单元格,而第二行有两个文本较小的单元格。
如何从 UICollectionViewCell 子类中的 UICollectionView 访问索引路径?我尝试了委托(delegate)协议(protocol),但这总是返回 nil。
下面的代码,非常感谢!
马库斯
UICollectionViewController:
import UIKit
protocol WorkoutDataViewControllerCVDataSource: AnyObject {
func workoutType(for workoutDataViewControllerCV: WorkoutDataViewControllerCV) -> WorkoutType
func workoutDistance(for workoutDataViewControllerCV: WorkoutDataViewControllerCV) -> Double
func workoutDuration(for workoutDataViewControllerCV: WorkoutDataViewControllerCV) -> Double
func workoutInstantVelocity(for workoutDataViewControllerCV: WorkoutDataViewControllerCV) -> Double
}
final class WorkoutDataViewControllerCV: UIViewController {
@IBOutlet weak var collectionView: UICollectionView!
weak var dataSource: WorkoutDataViewControllerCVDataSource!
private lazy var velocityFormatter = VelocityFormatter(dataSource: self, delegate: self)
private lazy var averageVelocityFormatter = VelocityFormatter(dataSource: self, delegate: self)
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView.register(MeasurementCollectionViewCell.preferredNib, forCellWithReuseIdentifier: MeasurementCollectionViewCell.preferredReuseIdentifier)
}
}
// MARK: - Managing UICollectionView
extension WorkoutDataViewControllerCV: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 4
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Measurement Cell", for: indexPath)
return cell
}
}
extension WorkoutDataViewControllerCV: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
let availableWidth = self.view.frame.width
switch indexPath.row {
case 0: return CGSize(width: availableWidth, height: 150)
case 1: return CGSize(width: availableWidth/2.1, height: 150)
case 2: return CGSize(width: availableWidth/2.1, height: 150)
case 3: return CGSize(width: availableWidth, height: 150)
default:
return CGSize(width: availableWidth/2.1, height: 150)
}
}
}
// MARK: - Managing VelocityFormatter
extension WorkoutDataViewControllerCV: VelocityFormatterDataSource {
func duration(for velocityFormatter: VelocityFormatter) -> Double {
return dataSource.workoutDuration(for: self)
}
func distance(for velocityFormatter: VelocityFormatter) -> Double {
return dataSource.workoutDistance(for: self)
}
func instantVelocity(for velocityFormatter: VelocityFormatter) -> Double {
return dataSource.workoutInstantVelocity(for: self)
}
}
UICollectionViewCell.swift
import UIKit
final class MeasurementCollectionViewCell: UICollectionViewCell {
@IBOutlet private var measurementPropertyLabel: UILabel!
@IBOutlet private var measurementValueLabel: UILabel!
@IBOutlet private var measurementUnitLabel: UILabel!
static let preferredReuseIdentifier = "Measurement Cell"
static let preferredNib = UINib(nibName: "MeasurementCollectionViewCell", bundle: nil)
override func awakeFromNib() {
super.awakeFromNib()
updateMeasurement(property: "Speed", value: "100", unit: "km/h")
//measurementValueLabel.font = measurementValueLabel.font.monospacedDigitFont
}
func updateMeasurement(property: String, value: String, unit: String?) {
measurementPropertyLabel.text = property
measurementValueLabel.text = value
measurementUnitLabel.text = unit
}
}
最佳答案
在UICollectionView delegate
方法collectionView(_, didSelectItemAt _)
中获取cell的实例。
extension WorkoutDataViewControllerCV: UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if let cell = collectionView.cellForItem(at: indexPath) as? MeasurementCollectionViewCell {
cell.selectedIndexPath(indexPath)
}
}
}
indexPath
将作为方法 selectedIndexPath
中的参数从上述方法传递到 MeasurementCollectionViewCell
。
class MeasurementCollectionViewCell: UICollectionViewCell {
......
func selectedIndexPath(_ indexPath: IndexPath) {
//Do your business here.
}
}
关于ios - 获取从 UICollectionViewController 到 UICollectionViewCell 子类的 indexPath,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/53193812/