删除单元格后更新 tableView 标题中的 UILabel

Question

我在 tableViewHeader 中有一个 UILabel，它显示 tableView 的行计数值。删除一行后，我想在删除一行后立即更新 tableViewHeader UILabel 中的计数值（所以不是在用户转到不同的 VC 和 returns 回到 tableView 之后然后刷新计数值）。同样，一旦从 tableView 中删除单元格，我希望 UILabel 值在同一视图中更新。感谢您的帮助！

// tableViewHeader class

class Header: UITableViewHeaderFooterView {

    var placeList = [Place]()
    var placesDictionary = [String: Place]()

    override init(reuseIdentifier: String?) {
        super.init(reuseIdentifier: reuseIdentifier)
        setupViews()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    let nameLabel: UILabel = {
        let label = UILabel()
        // display the number of tableView rows in UILabel
        label.text = "## of Places"
        label.translatesAutoresizingMaskIntoConstraints = false
        label.font = UIFont.boldSystemFont(ofSize: 14)
        return label
    }()

    func setupViews() {
        addSubview(nameLabel)
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-16-[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))
        addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))

    }
}

// headerView 方法

    override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        guard let view = tableView.dequeueReusableHeaderFooterView(withIdentifier: "headerId") as? Header else { return nil }
        view.nameLabel.text = "user has visited \(placeList.count) Places"
        return view
    }

//删除tableViewCell函数

    override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {

            if let place = placeList[indexPath.row].place {
                let uid = FIRAuth.auth()?.currentUser?.uid

                let ref = FIRDatabase.database().reference().child("users").child(uid!).child("Places")
                ref.queryOrdered(byChild: "place").queryEqual(toValue: place).observe(.childAdded, with: { (snapshot) in

                    snapshot.ref.removeValue(completionBlock: { (error, reference) in
                        if error != nil {
                            print("There has been an error:\(String(describing: error))")
                        }
                    })
                })
            }
            placeList.remove(at: indexPath.row)
            tableView.deleteRows(at: [indexPath], with: .left)
        }
    }

Answer 1

试试这个：

placeList.remove(at: indexPath.row)
tableView.beginUpdates()
tableView.deleteRows(at: [indexPath], with: .left)
tableView.reloadSections(IndexSet(integer: indexPath.section), with: .automatic)
tableView.endUpdates()

删除单元格后更新 tableView 标题中的 UILabel

update UILabel in tableViewHeader after cell is deleted

updates

uitableview

uilabel

delete-row

swift