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使用 UITextField 重用单元格的问题

分类：编程问答

如何解决使用 UITextField 重用单元格的问题

问题 1) 是：UITextFields 在提示后以随意的方式显示/隐藏文本。例如，您在名称字段中输入“john”，向上/向下滚动，您将在其他字段中看到“john”

问题 2) 滚动数据时提示消失，因此填充字段是有意义的。

细胞协议

protocol TableViewCellProtocol /*UpperDelegate*/ {

    var identity: String { get set }
    var cellClass: UITableViewCell.Type { get set }
    func config(cell: UITableViewCell)
}


extension UIView {
//    static var identifier: String { //usa questa nel mondo reale

    static var identifier_GivenByExtension: String {
        return String(describing: self)
    }
}

我的手机

protocol ValidationSimpleCell_Delegate: class {
    func getDataFromCell(fromCell: String,data: String)
    func canEnableButton(fromField: String,statusForEnableIs: Bool)
}

import UIKit

class ValidationSimpleCell: UITableViewCell {
    
    @IBOutlet weak var cellTextfield: UITextField!
    
    weak var delegate: ValidationSimpleCell_Delegate?
    private var model: ValidationSimpleCell_RowObject?
    
    
    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }
    
    override func setSelected(_ selected: Bool,animated: Bool) {
        super.setSelected(selected,animated: animated)
    }
    
    func configCell(_ model: ValidationSimpleCell_RowObject) {
        
        self.model = model
        delegate = model.delegate
        
        styleUI(model)
        
        cellTextfield.delegate = self
        
    }
    
    
    
    private func styleUI(_ model: ValidationSimpleCell_RowObject ) {
 
        self.backgroundColor = model.background

        self.cellTextfield.clearButtonMode = .whileEditing
        self.cellTextfield.placeholder = model.identity

        
        switch model.identity {
        case ProfileSections.firstSection.rawValue,ProfileSections.secondSection.rawValue:
            self.cellTextfield.isHidden = true
        default:
            self.cellTextfield.isHidden = false
        }

    }
    
    
}


//MARK: - object for tableView
class ValidationSimpleCell_RowObject: TableViewCellProtocol {
    
    var identity: String
    var cellClass: UITableViewCell.Type = ValidationSimpleCell.self
    var delegate: ValidationSimpleCell_Delegate?
    
    var background: UIColor
    
    init(
        delegate: ValidationSimpleCell_Delegate? = nil,identity: String,background: UIColor = .systemBackground
    ) {
        
        self.delegate = delegate
        self.identity = identity
        
        self.background = background
    }
    
    func config(cell: UITableViewCell) {
        (cell as? ValidationSimpleCell)?.configCell(self)
    }
}






extension ValidationSimpleCell: UITextFieldDelegate {
    
    //per la validazione sembra più affidabile
    func textFieldDidChangeSelection(_ textField: UITextField) {
        cell_CheckFieldsEmptiness(checkValidity: true)
        delegate?.getDataFromCell(fromCell: model?.identity ?? "N/A",data: textField.text ?? "N/aoA")
//        SC_cell_CheckFieldsEmptiness(cellTextfield: cellTextfield,model: self.model)
    }
 
    
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        
        
        if textField == cellTextfield {
            let _ = cellTextfield.resignFirstResponder()
        }
        
        return true
    }
    
    func textFieldShouldClear(_ textField: UITextField) -> Bool {
        cell_CheckFieldsEmptiness(checkValidity: true)
//        SC_cell_CheckFieldsEmptiness(cellTextfield: cellTextfield,model: self.model)

        return true
    }
    
   
    
    
}




protocol CellCanCheckDelegate {
    func cell_CheckFieldsEmptiness(checkValidity: Bool) //putt default = true
}

extension ValidationSimpleCell : CellCanCheckDelegate {

    func cell_CheckFieldsEmptiness(checkValidity: Bool = true) {

        let textFromTextfield = cellTextfield.text ?? ""
        var isLongEough = true
        var isMailValid = true
        if checkValidity {

            let isFieldEmpty = textFromTextfield.isEmpty

            if self.model?.identity == Fields.name.rawValue {
            }

            switch self.model?.identity {
            case Fields.name.rawValue:
//                isLongEough = isMinimumLong(text: testo,limit: 4)
                isLongEough = textFromTextfield.isMinimumLong(limit: 4)
                isLongEough = !textFromTextfield.isNumber()
            case Fields.mailAddress.rawValue:
                isMailValid = textFromTextfield.isValidEmail()
            default:
                break
            }

            if !isFieldEmpty && isLongEough && isMailValid {
                self.model?.delegate?.canEnableButton(fromField: self.model?.identity ?? "N/A",statusForEnableIs: true)
            } else {
                self.model?.delegate?.canEnableButton(fromField: self.model?.identity ?? "N/A",statusForEnableIs: false)
            }

        }
    }


}

视图控制器

enum ProfileSections: String,CaseIterable {
    case firstSection = "First Section"
    case secondSection = "Second Section"
}

enum Fields: String,CaseIterable {
    case name = "Type Your Name"
    case surname = "type Your Surname"
    case mailAddress = "type Your Email"
    case dato1
    case dato2
    case dato3
    case dato4
    case dato5
    case dato6
    case dato7
    case dato8
    case dato9
    case dato10


}

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var myTableView: UITableView!
    
    var rows: [TableViewCellProtocol] = []

    //usati per validazione
    @IBOutlet weak var footerButtonOut: UIButton!
    
    private var TEMP_Name = false
    private var theName = ""
    
    private var TEMP_surname = false
    private var theSurname = ""
    
    private var TEMP_mail = false
    private var theMail = ""
    
    private var goingForwards = false
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        setUpTableView()
    
        fillRowsWithObjects()
        self.footerButtonOut.isEnabled = false
     
    }
    
    

    private func setUpTableView() {
        
        myTableView.delegate = self
        myTableView.dataSource = self
        myTableView.tableFooterView = UIView() //hides unwanted rows
    }
    
    
    private func fillRowsWithObjects() {
        self.rows = []
        
        for section in ProfileSections.allCases {
      
            self.rows.append(ValidationSimpleCell_RowObject(delegate: nil,identity: section.rawValue,background: .lightGray))

            switch section {
            case .firstSection:
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.name.rawValue))
            case .secondSection:
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.surname.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.mailAddress.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato1.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato2.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato3.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato4.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato5.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato6.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato7.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato8.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato9.rawValue))
                self.rows.append(ValidationSimpleCell_RowObject(delegate: self,identity: Fields.dato10.rawValue))
                break
            }
            
        }
        
        self.myTableView.reloadData()
    }
    
    
    @IBAction func footerButtonTapped(_ sender: Any) {
        print("tapped")
    }
    
}




//MARK: - tableView section
extension ViewController: UITableViewDelegate {
    
    func tableView(_ tableView: UITableView,didSelectRowAt indexPath: IndexPath) {
        
        let selected = self.rows[indexPath.row]
        
//        switch selected.identity {
//        case Fields.name.rawValue:
//            print("go to name")
//        case Fields.surname.rawValue:
//            print("go to surname")
//        case Fields.mailAddress.rawValue:
//            print("got o mail")
//        default:
//            break
//        }
        
        self.myTableView.deselectRow(at: indexPath,animated: true)
    }
    
}

extension ViewController: UITableViewDataSource {
    
    func tableView(_ tableView: UITableView,numberOfRowsInSection section: Int) -> Int {
        return self.rows.count
    }
    
    func tableView(_ tableView: UITableView,cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let model = rows[indexPath.row]
        
        let cell = self.myTableView.dequeueReusableCell(withIdentifier: model.cellClass.identifier_GivenByExtension,for: indexPath)
        model.config(cell: cell)
        
        return cell
        
    }
    
}


extension ViewController: ValidationSimpleCell_Delegate {
     
    func canEnableButton(fromField: String,statusForEnableIs: Bool) {
        
        switch fromField {
        case Fields.name.rawValue:
            self.TEMP_Name = statusForEnableIs
        case Fields.surname.rawValue:
            self.TEMP_surname = statusForEnableIs
        case Fields.mailAddress.rawValue:
            self.TEMP_mail = statusForEnableIs
        default:
            break
        }
        
        let requiredFields = TEMP_Name && TEMP_surname && TEMP_mail
        if requiredFields {
            self.footerButtonOut.isEnabled = true
        } else {
            self.footerButtonOut.isEnabled = false
        }
        
    }
    
    func getDataFromCell(fromCell: String,data: String) {
        
        switch fromCell {
        case Fields.name.rawValue:
            self.theName = data
        print("SAVE ON USEDEF \(data)")
        case Fields.surname.rawValue:
            self.theSurname = data
        print("SAVE ON USEDEF \(data)")
        case Fields.mailAddress.rawValue:
        print("SAVE ON USEDEF \(data)")
        default:
            break
        }
        
    }
}

解决方法

  • 您需要阅读有关可重用单元格的内容；)
  • 将值存储在控制器中并在 cellForRowAt 的单元格中显示它们...
  • 当您更改单元格中的某些值时，您还应该将它们存储（闭包，委托...）在控制器中

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