使用MVP模式iOS将数据传递到另一个控制器

Question

我正在使用MVP设计模式。我有两种将数据传递到另一个视图控制器的方式，我将在下面提到。我不知道其中哪个是正确的，并且没有违反MVP模式。我知道这是一个很大的问题，但这确实非常重要。

1）下面使用init with presenter通过传递视图控制器所需的演示者来创建视图控制器。

struct HotelTemplate {
    var id: String
    var name: String
    var icon: String
}

class ListHotelPresenter: NSObject {

    private var data = [HotelTemplate]()

    func getPresenter(_ index: Int) -> HotelDetailsPresenter {
        let presenter = HotelDetailsPresenter(id: data[index].id, name: data[index].name, icon: data[index].icon)
        return presenter
    }
}

// InitialViewController
class ListHotelViewController: UIViewController {

    class func `init`(with presenter: ListHotelPresenter) -> ListHotelViewController {
        let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ListHotelViewController") as! ListHotelViewController
        vc.presenter = presenter
        return vc
    }

    var presenter: ListHotelPresenter!

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let detailPresenter = presenter.getPresenter(indexPath.row)
        let vc = HotelDetailsViewController.init(with: detailPresenter)
        self.navigationController?.pushViewController(vc, animated: true)
    }
}

// ViewController that will be push
class HotelDetailsViewController: UIViewController {

    class func `init`(with presenter: HotelDetailsPresenter) -> HotelDetailsViewController {
        let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "HotelDetailsViewController") as! HotelDetailsViewController
        return vc
    }

    var presenter: HotelDetailsPresenter!

    override func viewDidLoad() {
        super.viewDidLoad()

        presenter.loadHoteData()
    }
}

class HotelDetailsPresenter: NSObject {
    var hotelId: String
    var hotelName: String
    var hotelIcon: String

    init(id: String, name: String, icon: String) {
        self.hotelId = id
        self.hotelName = name
        self.hotelIcon = icon
    }

    func loadHoteData() {
        // Load hotel data.
        // Alamofire.request ..................
    }
}

2）通过发送id, name, icon，然后在viewDidLoad()中初始化演示者

struct HotelTemplate {
    var id: String
    var name: String
    var icon: String
}

class ListHotelPresenter: NSObject {

    private var data = [HotelTemplate]()

    func getHotelName(_ index: Int) -> String {
        return data[index].name
    }

    func getHotelIcon(_ index: Int) -> String {
        return data[index].icon
    }

    func getHotelId(_ index: Int) -> String {
        return data[index].id
    }
}

class ListHotelViewController: UIViewController {

    var presenter: ListHotelPresenter!

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "HotelDetailsViewController") as! HotelDetailsViewController
        vc.id = presenter.getHotelId(indexPath.row)
        vc.name = presenter.getHotelName(indexPath.row)
        vc.icon = presenter.getHotelIcon(indexPath.row)
        self.navigationController?.pushViewController(vc, animated: true)
    }
}

class HotelDetailsViewController: UIViewController {

    var presenter: HotelDetailsPresenter!
    var id = ""
    var name = ""
    var icon = ""

    override func viewDidLoad() {
        super.viewDidLoad()
        presenter = HotelDetailsPresenter(id: id, name: name, icon: icon)
        presenter.loadHoteData()
    }
}

class HotelDetailsPresenter: NSObject {
    var hotelId: String
    var hotelName: String
    var hotelIcon: String

    init(id: String, name: String, icon: String) {
        self.hotelId = id
        self.hotelName = name
        self.hotelIcon = icon
    }

    func loadHoteData() {
        // Load hotel data.
        // Alamofire.request ..................
    }
}

以下是我的担忧：

1）哪个是正确的？ （我觉得第一种方法确实很干净，但我的上级告诉我，这违反了MVP模式。我不知道怎么做。）

2）控制器的演示者属性应该是公共的还是私有的？

Answer 1

嘿，按照苹果公司的指导Model-View-Controller都可以，但是第二个更易读且易于理解，请先检查代码。

class ListHotelViewController: UIViewController{
private var presenter: ListHotelPresenter!

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "HotelDetailsViewController") as! HotelDetailsViewController
    vc.objHotelTemplate = presenter.getHotelTemplate(indexPath.row)
    self.navigationController?.pushViewController(vc, animated: true)
}
}
class HotelDetailsViewController: UIViewController {

private var presenter: HotelDetailsPresenter!
var objHotelTemplate:HotelTemplate!

override func viewDidLoad() {
    super.viewDidLoad()
    presenter = HotelDetailsPresenter(id: objHotelTemplate.id, name: objHotelTemplate.name, icon: objHotelTemplate.icon)
    presenter.loadHoteData()
}

}

Answer 2

在Objective-C中，您可以拥有一个可以传递模型的视图。我们可以在视图控制器的头文件中向前声明一个模型：

@class HotelTemplate;

在.m文件中，请确保不要"#import HotelTemplate.h"。这样，模型仍然不透明。您可以将其传递，但​​是不能向内看。

我不知道有什么方法可以在Swift中执行。因此，让我按照您的示例并通过下一个演示者，而不是下一个模型。我们需要的是一种在viewDidLoad()中的每个演示者上设置“视图”的方法。为了防止保留周期，这将是一个较弱的属性。

首先，这是列表视图控制器。我做了一个UITableViewController。

final class ListHotelViewController: UITableViewController {
    private var presenter = ListHotelPresenter()

    override func viewDidLoad() {
        super.viewDidLoad()
        presenter.setView(self)
        presenter.loadHotelData()
    }
}

演示者将通过协议将其回调：

protocol ListHotelView: class {
    func redraw()
    func showDetails(nextPresenter: HotelDetailsPresenter)
}

extension ListHotelViewController: ListHotelView {
    func redraw() {
        tableView.reloadData()
    }

    func showDetails(nextPresenter: HotelDetailsPresenter) {
        let vc = HotelDetailsViewController.init(with: nextPresenter)
        navigationController?.pushViewController(vc, animated: true)
    }
}

这是表视图的数据源和委托：

extension ListHotelViewController /* UITableViewDataSource */ {
    public override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return presenter.hotelCount
    }

    public override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Hotel", for: indexPath) as! HotelTableViewCell
        presenter.configure(cell: cell, row: indexPath.row)
        return cell
    }
}

extension ListHotelViewController /* UITableViewDelegate */ {
    public override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        presenter.showDetails(row: indexPath.row)
    }
}

在每个步骤中，它都向主持人提出。演示者有一个薄弱的链接返回到视图，但只能通过协议。不知道View是ListHotelViewController。对于基于终端的接口，我们应该能够使用一堆print(_)语句来实现View。

final class ListHotelPresenter {
    private weak var view: ListHotelView?
    private var model: [HotelTemplate] = [] {
        didSet {
            view?.redraw()
        }
    }

    var hotelCount: Int {
        return model.count
    }

    func setView(_ view: ListHotelView) {
        self.view = view
    }

    func loadHotelData() {
        // Network request to load data into model. Let's pretend with dummy data:
        let hilton = HotelTemplate(id: "hilton", name: "Hilton", icon: "H")
        let radisson = HotelTemplate(id: "radisson", name: "Radisson", icon: "R")
        model = [hilton, radisson]
    }

    func configure(cell: HotelCell, row: Int) {
        let hotel = model[row]
        cell.show(name: hotel.name, icon: hotel.icon)
    }

    func showDetails(row: Int) {
        let nextPresenter = HotelDetailsPresenter(summaryModel: model[row])
        view?.showDetails(nextPresenter: nextPresenter)
    }
}

在configure(cell:row:)中，主持人与给定的单元格对话。请注意，单元格也是协议。借助MVP，我真的试图想象如何使用它来创建基于终端的界面。这是单元格：

protocol HotelCell: class {
    func show(name: String, icon: String)
}

final class HotelTableViewCell: UITableViewCell {}

extension HotelTableViewCell: HotelCell {
    func show(name: String, icon: String) {
        textLabel?.text = name
        // Do something to show icon
    }
}

实际上，您可以向表格视图单元格中添加更多内容。在此示例中，我只使用了一个普通单元格及其文本标签。

最后，我们来到推送视图控制器。

final class HotelDetailsViewController: UIViewController {
    private var presenter: HotelDetailsPresenter!
    @IBOutlet private var textLabel: UILabel!

    static func `init`(with presenter: HotelDetailsPresenter) -> HotelDetailsViewController {
        let vc = UIStoryboard(name: "Main", bundle: nil)
                .instantiateViewController(withIdentifier: "HotelDetailsViewController")
                as! HotelDetailsViewController
        vc.presenter = presenter
        return vc
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        presenter.setView(self)
        presenter.show()
    }
}

我假设我们将立即显示所拥有的摘要信息，但是从Web服务中可以获取更多细节。这是由这个演示者完成的。

struct HotelDetails {
    let location: String
    // more details…
}

final class HotelDetailsPresenter {
    private weak var view: HotelDetailsView?
    private let summaryModel: HotelTemplate        
    private var detailsModel: HotelDetails? {
        didSet {
            guard let detailsModel = detailsModel else { return }
            view?.showDetails(location: detailsModel.location)
        }
    }

    init(summaryModel: HotelTemplate) {
        self.summaryModel = summaryModel
    }

    func setView(_ view: HotelDetailsView) {
        self.view = view
    }

    func show() {
        view?.show(name: summaryModel.name, icon: summaryModel.icon)
        // Network request to load data into detailsModel
    }
}

与往常一样，主持人告诉View通过协议进行的操作：

protocol HotelDetailsView: class {
    func show(name: String, icon: String)
    func showDetails(location: String)
}

extension HotelDetailsViewController: HotelDetailsView {
    func show(name: String, icon: String) {
        textLabel?.text = name
        // Do something to show icon
    }

    func showDetails(location: String) {
        // Show other hotel details we loaded
    }
}

如您所见，属性是私有的。为了支持单元测试，我们可能需要使用private(set)放宽它，以便仅设置器是私有的。