ios - UITableView - 在滚动时它会丢失与选定单元格关联的属性。如何保存这些属性？ - swift

Question

我有一个带有自定义弹出窗口的应用程序，其中包含一个表格 View (见下文)。当我点击一个复选框(UIButton)时，我换掉了背景图像并在选中和未选中之间切换。当我有一个选中的框时，当我向上或向下滚动时，选中的框默认恢复为未选中。请有人建议如何在滚动时保持每个单元格的选中状态？

 class CustomHashTagPopup: UIViewController, UITableViewDelegate, UITableViewDataSource{


// CREATE TABLEVIEW CELLS
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell = self.tableViewPicker.dequeueReusableCell(withIdentifier: "pickerCell") as! PreviewTableViewCustomPickerCell

    if(indexPath == [0,0]){
        let image = UIImage.init(named: "add")
        cell.checkBoxOutlet.setBackgroundImage(image!, for: .normal)
        cell.pickerLabel.text = "Create New HashTag"
        cell.isCreateTagCell = true

    }else{
        let image = UIImage.init(named: "uncheck")
        cell.checkBoxOutlet.setBackgroundImage(image!, for: .normal)
        cell.pickerLabel.text = arrayHashTags[indexPath.row]
        cell.isCreateTagCell = false
    }
    return cell

}


 }


 class PreviewTableViewCustomPickerCell: UITableViewCell {

 var isSelect: Bool = false
var isCreateTagCell: Bool = false // TO DISTINGUISH 'CEATE NEW HASHTAG OPTION'



/*** OUTLETS ***/

@IBOutlet weak var checkBoxOutlet: UIButton!
@IBOutlet weak var pickerLabel: UILabel!


 // TAP ON CHECK BOX
@IBAction func checkBoxBtn(_ sender: Any) {


    if(isSelect == false && isCreateTagCell == false){
        isSelect = true
        // SHOW GREEN SELECTED CHECK BOX
        let image = UIImage.init(named: "tick")
        self.checkBoxOutlet.setBackgroundImage(image!, for: .normal)

    }else if(isSelect == true && isCreateTagCell == false){
        isSelect = false
        // SHOW UNCHECKED BOX
        let image = UIImage.init(named: "uncheck")
        self.checkBoxOutlet.setBackgroundImage(image!, for: .normal)
    }
}

Answer 1

你错过的是 cell-reusing ，你必须将每个 Action 存储在模型数组中并检查当前值并在 cellForRowAt 中设置适当的设置，你可以设置 Action 的委托(delegate)到 cellForRowAt 内按钮的 vc，以便在用户单击特定 indexPath 处的按钮时轻松访问模型数组以对其进行操作，因此请考虑像这样声明数组

let arr = [false,true,false,false,false] first index is dummy as it will be skipped in Create New HashTag

//

@objc func btnClicked(_ sender:UIButton) {
   arr[sender.tag] = !arr[sender.tag]
    // reload indexPath of row = sender.tag , section = 0
}

//

在 cellForRowAt 内部

if (indexPath == [0,0]) {
    let image = UIImage(named: "add")
    cell.checkBoxOutlet.setBackgroundImage(image!, for: .normal)
    cell.pickerLabel.text = "Create New HashTag"
    cell.isCreateTagCell = true

}else{
    let image = UIImage(named: arr[indexPath.row] ? "tick" : "uncheck") // edited here 
    cell.checkBoxOutlet.setBackgroundImage(image!, for: .normal)
    cell.pickerLabel.text = arrayHashTags[indexPath.row]
    cell.isCreateTagCell = false
}

cell.button.addTarget(self, action: #selector(btnClicked(_:)), for: .touchUpInside)
cell.button.tag = indexPath.row