不同对象的UITableViewDiffableDataSource和NSDiffableDataSourceSnapshot仅显示一行 [英] UITableViewDiffableDataSource and NSDiffableDataSourceSnapshot for different objects shows only one row

问题描述

我已经使用 UITableViewDiffableDataSource 和 NSDiffableDataSourceSnapshot 这样的

    private typealias ListDataSource = UITableViewDiffableDataSource<Section, Wrapper> 
    private typealias ListSnapshot = NSDiffableDataSourceSnapshot<Section, Wrapper>


 enum Wrapper: Hashable {
    case one([Company])
    case two([Member])
}

private enum Section: CaseIterable {
    case main
}

private func configureDataSource() {

        dataSource = ListDataSource(tableView: listTableView,
                                    cellProvider: { [weak self] (_, indexPath, wrapper) -> UITableViewCell? in

                                        guard let `self` = self else {
                                            return UITableViewCell()
                                        }
                                        switch wrapper {

                                        case .one(let company):
                                            let cell = self.listTableView.dequeueReusableCell(withIdentifier: "Cell",
                                                                                              for: indexPath)
                                            cell.textLabel?.text = company[indexPath.row].name
                                            return cell
                                        case .two(let member):

                                            let cell = self.listTableView.dequeueReusableCell(withIdentifier: "Cell",
                                                                                              for: indexPath)
                                            cell.textLabel?.text = member[indexPath.row].name.first
                                            return cell
                                        }
        })

    }

func updateData(_ wrapper: Wrapper) {
        var snapshot = ListSnapshot()
        snapshot.appendSections([.main])

        switch  wrapper {
        case .one(let comp):
            snapshot.appendItems([.one(comp)])
            dataSource.apply(snapshot, animatingDifferences: true)
        case .two(let member):
            snapshot.appendItems([.two(member)])
            dataSource.apply(snapshot, animatingDifferences: true)
        }
    }

有关段更改的信息，更新包装器类型的数据.但是问题只是每次只显示一条记录.

func handleSegmentChanged(_ sender: UISegmentedControl) {

   

 let member = Member(name: Name(first: "Harshal", last: "Wani"),
                        memberId: "123", age: 30, email: "[e-mail]", phone: "123456789")
    let member2 = Member(name: Name(first: "David", last: "John"),
                        memberId: "123", age: 30, email: "[e-mail]", phone: "123456789")

    let comp = Company(name: "Comp 1", companyId: "", website: "", logo: "", about: "", members: [member, member2])
    let comp2 = Company(name: "Comp 2", companyId: "", website: "", logo: "", about: "", members: [member, member2])

    if sender.selectedSegmentIndex == 0 {
        updateData(.one([comp, comp2]))
    } else {
        updateData(.two(comp.members))
    }
}

感谢您的帮助，谢谢

推荐答案

每个部分仅应用一项，则必须声明包装器

You are applying only one item per section, you have to declare the wrapper

enum Wrapper: Hashable {
    case one(Company)
    case two(Member)
}

在 handleSegmentChanged 中创建由 Wrapper 项目组成的 array 而不是由 one Wrapper 带有相关类型的数组.

In handleSegmentChanged create an array of Wrapper items instead of one Wrapper with an array of associated types.

@IBAction func handleSegmentChanged(_ sender: UISegmentedControl) {
    
    let member = Member(name: Name(first: "Harshal", last: "Wani"), memberId: "123", age: 30, email: "[e-mail]", phone: "123456789")
    let member2 = Member(name: Name(first: "David", last: "John"), memberId: "123", age: 30, email: "[e-mail]", phone: "123456789")
    
    let comp = Company(name: "Comp 1", companyId: "", website: "", logo: "", about: "", members: [member, member2])
    let comp2 = Company(name: "Comp 2", companyId: "", website: "", logo: "", about: "", members: [member, member2])
    
    if sender.selectedSegmentIndex == 0 {
        updateData([.one(comp), .one(comp2)])
    } else {
        updateData(comp.members.map{.two($0)})
    }
}

并将 updateData 替换为

func updateData(_ wrapper: [Wrapper]) {
    var snapshot = ListSnapshot()
    snapshot.appendSections([.main])
    snapshot.appendItems(wrapper)
    dataSource.apply(snapshot, animatingDifferences: true)
}

[弱自我]-> configureDataSource 中的self 跳舞是胡说八道.闭包的第一个参数是表格视图.使用此实例可避免发生 self 的任何情况，并将 configureDataSource 替换为

The [weak self] -> self dance in configureDataSource is nonsense. The first parameter of the closure is the table view. Use this instance to avoid any occurrence of self and replace configureDataSource with

 private func configureDataSource() {
    
    dataSource = ListDataSource(tableView: listTableView,
                                cellProvider: { (tableView, indexPath, wrapper) -> UITableViewCell? in
                                    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell",
                                                                                        for: indexPath)
                                    switch wrapper {
                                        case .one(let company):
                                            cell.textLabel?.text = company.name
                                        case .two(let member):
                                            cell.textLabel?.text = member.name.first
                                    }
                                    return cell
    })
}

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