我正在尝试设计我自己的 UITableViewCell,以便在 AccessoryView 中包含一个 Stepper。因此,我想添加选择器,以便 ViewController 能够处理被更改的值的行为。 (UITableViewCell 应该只负责在其标签中显示结果)
目前,我可以通过对 UITableViewCell 类使用 addTarget 来修改标签的文本,但是当我将目标添加到 UITableViewController 类时,出现以下错误:
2018-10-08 20:04:39.157912-0400 MyProject[1003:45273] -[MyProject expansionSelectionValueDidChange:]: unrecognized selector sent to instance 0x7fa88700fc00
2018-10-08 20:04:39.167219-0400 MyProject[1003:45273] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[MyProject.PlayerSelectionCell expansionSelectionValueDidChange:]: unrecognized selector sent to instance 0x7fa88700fc00'
我正在使用 X-Code 10 和 Swift 4 开发 iOS 12 应用程序。
这是 UITableViewCell 的代码:
class PlayerSelectionCell: UITableViewCell {
@objc func stepperValueDidChange(_ sender: UIStepper) {
textLabel?.text = "\(newValue) Players"
}
override func awakeFromNib() {
let stepper = UIStepper()
stepper.addTarget(self, action: #selector(stepperValueDidChange(_:)), for: .valueChanged)
stepper.addTarget(self, action: #selector(SetupViewController.expansionSelectionValueDidChange(_:)), for: .valueChanged)
self.accessoryView = stepper
}
}
这是我的 UITableViewController 的代码
class SetupViewController: UITableViewController {
@IBOutlet var setupTableView: UITableView!
override func numberOfSections(in tableView: UITableView) -> Int {
return 2
}
override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
switch section {
case 0:
return "Expansions"
case 1:
return "Players"
default:
return nil
}
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
switch section {
case 0:
return Expansions.allCases.count
case 1:
return 3
default:
return 0
}
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 0 {
let cell = tableView.dequeueReusableCell(withIdentifier: "Expansion Selection", for: indexPath) as? ExpansionCell ?? ExpansionCell()
cell.textLabel?.text = Expansions.allCases[indexPath.row].rawValue
return cell
} else if indexPath.section == 1 && indexPath.row == 0 {
let cell = tableView.dequeueReusableCell(withIdentifier: "Player Selection", for: indexPath) as? PlayerSelectionCell ?? PlayerSelectionCell()
return cell
} else {
let cell = tableView.dequeueReusableCell(withIdentifier: "Player Detail", for: indexPath) as? PlayerCell ?? PlayerCell()
cell.textLabel?.text = "Player \(indexPath.row)"
return cell
}
}
@objc func playerCountValueDidChange(_ sender: UIStepper) {
print("Value : \(sender.value)")
}
@objc func expansionSelectionValueDidChange(_ sender: UISwitch) {
print("Value : \(sender.isOn)")
}
override func viewDidLoad() {
super.viewDidLoad()
}
}
最佳答案
替代公认的解决方案:
根据情况,您可以尝试使用委托(delegate)代替操作/目标
//Declare a delegate for the cell
protocol PlayerSelectionCellDelegate : class {
func playerSelectionCell(_ cell:PlayerSelectionCell, didChangeValue:Double)
func playerSelectionCell(_ cell:PlayerSelectionCell, expansionSelectionValueDidChange:Bool)
}
class PlayerSelectionCell: UITableViewCell {
weak var delegate : PlayerSelectionCellDelegate? //Set a weak var to allocate the delegate
@objc func stepperValueDidChange(_ sender: UIStepper) {
delegate?.playerSelectionCell(self, didChangeValue: sender.value)
}
@objc func expansionSelectionValueDidChange(_ sender: UISwitch) {
delegate?.playerSelectionCell(self, expansionSelectionValueDidChange: sender.isOn)
}
override func awakeFromNib() {
let stepper = UIStepper()
stepper.addTarget(self, action: #selector(stepperValueDidChange), for: .valueChanged)
//This line should be reference to the UISwitch Action
selectionSwitch.addTarget(self, action: #selector(expansionSelectionValueDidChange), for: .valueChanged)
self.accessoryView = stepper
}
}
在 ViewController 中,您更改代码以符合委托(delegate)并将 ViewController 设置为委托(delegate)给单元格
class SetupViewController: UITableViewController {
@IBOutlet var setupTableView: UITableView!
override func numberOfSections(in tableView: UITableView) -> Int {
return 2
}
override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
switch section {
case 0:
return "Expansions"
case 1:
return "Players"
default:
return nil
}
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
switch section {
case 0:
return Expansions.allCases.count
case 1:
return 3
default:
return 0
}
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 0 {
let cell = tableView.dequeueReusableCell(withIdentifier: "Expansion Selection", for: indexPath) as? ExpansionCell ?? ExpansionCell()
cell.textLabel?.text = Expansions.allCases[indexPath.row].rawValue
return cell
} else if indexPath.section == 1 && indexPath.row == 0 {
let cell = tableView.dequeueReusableCell(withIdentifier: "Player Selection", for: indexPath) as? PlayerSelectionCell ?? PlayerSelectionCell()
cell.delegate = self //Set the ViewController to be delegated by cell
return cell
} else {
let cell = tableView.dequeueReusableCell(withIdentifier: "Player Detail", for: indexPath) as? PlayerCell ?? PlayerCell()
cell.textLabel?.text = "Player \(indexPath.row)"
return cell
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
//Remove the actions and implements the delegate methods
func playerSelectionCell(_ cell: PlayerSelectionCell, didChangeValue players: Double) {
print("Value Players: \(players)")
}
func playerSelectionCell(_ cell: PlayerSelectionCell, expansionSelectionValueDidChange selected: Bool) {
print("Value Selected: \(selected)")
}
}
关于ios - 将 UITableViewCell 类中的选择器添加到 UITableViewController 类,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/52711733/