使用 RxSwift 从 UITableViewCell 发送回调到 UIViewController

Question

我有一个 UITableViewCell，其中有 customContentView，我想向 viewController 发送回调。为此，我正在使用 RxSwift。

class GISThemeFormTableCell: UITableViewCell {

    @IBOutlet weak var customContentView: UIView!

    var index = -1

    var cellSelected: Observable<(Int, Bool)>?
    private var observer: AnyObserver<(Int, Bool)>?

    override func awakeFromNib() {
        super.awakeFromNib()

        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(self.didSelectCell))
        customContentView.addGestureRecognizer(tapGesture)

        cellSelected = Observable<(Int, Bool)>.create { (observer) -> Disposable in
            self.observer = observer
            return Disposables.create()
        }
    }

    @objc private func didSelectCell() {
        let newImage = selectionImageView.image! == Images.uncheckedRound ? Images.checkedRound : Images.uncheckedRound
        selectionImageView.image = newImage
        observer?.onNext((index, selectionImageView.image! == Images.checkedRound))
    }
}

class GISFormListView: UIView {

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        switch indexPath.section {
        case 0:
            let cell = tableView.dequeueReusableCell(withIdentifier: "GISThemeFormTableCell", for: indexPath) as! GISThemeFormTableCell
            cell.index = indexPath.row
            cell.formTitle.text = presenter.getFormName(indexPath.row)

            cell.cellSelected?.subscribe { (event) in
                let index = event.element!.0
                let isSelected = event.element!.1

                print(index, isSelected)

            }.disposed(by: disposeBag)

            return cell

        case 1:
            let cell = tableView.dequeueReusableCell(withIdentifier: "LoadingTableViewCell", for: indexPath) as! LoadingTableViewCell
            return cell

        default:
            return UITableViewCell()
        }
    }
}

在上面的代码中，我在 awakeFromNib 方法中创建了 Observable，并在那里初始化了观察者。调用 didSelectCell 方法后，我将在观察者中传递单元格和 bool 的索引。

如果我不想使用闭包和委托，我只是想知道这是否是实现此目标的正确方法。

Answer 1

如果您有兴趣，这里有一个更完整的答案。我看到@Erumaru 警告过您多次打印单元格。如果您有足够多的表单项导致某些单元格被重复使用并且您没有正确处理，那么请记住这一点。

class GISThemeFormTableCell: UITableViewCell {

    @IBOutlet weak var formTitle: UILabel!
    @IBOutlet weak var selectionImageView: UIImageView!
    @IBOutlet weak var customContentView: UIView!

    var disposeBag = DisposeBag()

    private var tapGesture: UITapGestureRecognizer = UITapGestureRecognizer(target: nil, action: nil)

    override func awakeFromNib() {
        super.awakeFromNib()
        customContentView.addGestureRecognizer(tapGesture)
    }

    override func prepareForReuse() {
        super.prepareForReuse()
        disposeBag = DisposeBag()
    }

    func configure(title: String, initial: Bool = false) -> Observable<Bool> {
        // you shouldn't be inspecting your views to figure out the state of your model. The code below avoids that by making the state its own thing.
        let state = tapGesture.rx.event
            .filter { $0.state == .ended }
            .scan(false) { current, _ in !current }
            .startWith(initial)

        state
            .map { $0 ? Images.checkedRound : Images.uncheckedRound }
            .bind(to: selectionImageView.rx.image)
            .disposed(by: disposeBag)

        return state
    }
}

class GISFormListView: UIView {

    var presenter: Presenter!

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        switch indexPath.section {
        case 0:
            let cell = tableView.dequeueReusableCell(withIdentifier: "GISThemeFormTableCell", for: indexPath) as! GISThemeFormTableCell
            // the cell doesn't need to know its row, because that information is needed here, and it's already here.
            cell.configure(title: presenter.getFormName(indexPath.row))
                .map { (indexPath.row, $0) }
                .subscribe(onNext: { index, isSelected in
                    print(index, isSelected)
                })
                .disposed(by: cell.disposeBag)

            return cell

        case 1:
            let cell = tableView.dequeueReusableCell(withIdentifier: "LoadingTableViewCell", for: indexPath) as! LoadingTableViewCell
            return cell

        default:
            return UITableViewCell()
        }
    }
}

Answer 2

在您的单元格中创建disposeBag。然后，在prepareForReuse 中重置它。

cell.cellSelected?.subscribe { (event) in
    let index = event.element!.0
    let isSelected = event.element!.1
}.disposed(by: cell.disposeBag)

在您的情况下，经过一些滚动后，每个单元格将被多次订阅。这应该会带来一些魔力:)

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一般来说，您只会订阅可见的单元格，并且不会发生内存泄漏或过度计算。对我来说似乎没问题。