ReloadData 后 UIScrollView 崩溃

Question

我在 tableView 的每一行都有 ScrollView。我正在为其分配不同的标签。 它第一次完美运行。当更改数组中的数据并使 ReloadData App 崩溃时。

错误是这样的

致命错误：在展开可选值时意外发现 nil

一段代码

 cell = tableView.dequeueReusableCell(withIdentifier: "ContentCell", for: indexPath)
                let lblName = (cell.viewWithTag(31)! as! UILabel)
                let lblSubmited = (cell.viewWithTag(32)! as! UILabel)
                let lblFrom = (cell.viewWithTag(33)! as! UILabel)
                let lblTo = (cell.viewWithTag(34)! as! UILabel)
                let lblTotalHours = (cell.viewWithTag(35)! as! UILabel)
                let lblapprove = (cell.viewWithTag(36)! as! UILabel)

                lblName.text = dict.object(forKey: "name") as? String
                lblSubmited.text = dict.object(forKey: "submitted") as? String
                lblFrom.text = dict.object(forKey: "from") as? String
                lblTo.text = dict.object(forKey: "to") as? String
                lblTotalHours.text = dict.object(forKey: "tot") as? String
                lblapprove.text = "Pending"

                let scrollView:UIScrollView!
                if(flag.object(at: indexPath.row) as! String == "0"){
                        scrollView = (cell.viewWithTag(3)! as! UIScrollView)
                        scrollView.tag = ((100 * indexPath.row)+1)
                        flag.replaceObject(at: indexPath.row, with: "1")
                }
                else{
                    scrollView = (cell.viewWithTag(((100 * indexPath.row)+1))! as! UIScrollView)
                }

            scrollView.delegate = self
            scrollView.showsHorizontalScrollIndicator = false

            let viewContent = (cell.viewWithTag(1000)!)
            let btApprove = UIButton(frame: CGRect(x: 704.0, y: 10.0, width: 40.0, height: 40.0))
            let btReject = UIButton(frame: CGRect(x: 788.0, y: 10.0, width: 40.0, height: 40.0))
            let btDetail = UIButton(frame: CGRect(x: 860.0, y: 10.0, width: 40.0, height: 40.0))

            btApprove.addTarget(self, action: #selector(self.approvePressedAction), for: .touchUpInside)
            btReject.addTarget(self, action: #selector(self.rejectPressedAction), for: .touchUpInside)
            btDetail.addTarget(self, action: #selector(self.detailPressedAction), for: .touchUpInside)

            viewContent.addSubview(btApprove)
            viewContent.addSubview(btReject)
            viewContent.addSubview(btDetail)

  return cell

错误来了

scrollView = (cell.viewWithTag(3)!as!UIScrollView)

重新加载数据后线路和崩溃。有什么解决办法吗？

Answer 1

似乎您正在强制解开很多选项，也许在尝试使用它们之前先检查它们。

我不知道您的逻辑在做什么，但是要对崩溃的特定行进行一些检查，请尝试这样的操作。

var scrollView:UIScrollView!
if(flag.object(at: indexPath.row) as! String == "0"){
    if let view = cell.viewWithTag(3) {
        if let sv = view as? UIScrollView {
            scrollView = sv
            scrollView.tag = ((100 * indexPath.row)+1)
            flag.replaceObject(at: indexPath.row, with: "1")
        } else {
            print("view found with tag 3 but it's not a scrollview")
        }
    } else {
        print("no view found with tag 3")
    }
} else {
    scrollView = (cell.viewWithTag(((100 * indexPath.row)+1))! as! UIScrollView)
}