代碼下載

復雜UITableview綁定Rx實現(xiàn)

RxCocoa沒有實現(xiàn)復雜UITableview數(shù)據(jù)綁定（如多組數(shù)據(jù)、cell編輯等），需要自行實現(xiàn)，不過通過對RxCocoa中UITableview單組數(shù)據(jù)綁定的分析，其實實現(xiàn)思路是一樣的。

定義一個SectionModelType協(xié)議來規(guī)范整個組的數(shù)據(jù)：

protocol SectionModelType {
    associatedtype Section
    associatedtype Item
    
    var model: Section { get }
    var items: [Item] { get }
    
    init(model: Section, items: [Item])
}

• 定義了兩個關聯(lián)類型Section，Item表示組數(shù)據(jù)和組中的行數(shù)據(jù)
• 定義兩個屬性model，items存儲組數(shù)據(jù)和組中的行數(shù)據(jù)

定義一個SectionModelType類來存儲、關聯(lián)源數(shù)據(jù)的數(shù)據(jù)：

class SectionedDataSource<Section: NSObject, SectionModelType>: SectionedViewDataSourceType {
    
    private var _sectionModels: [Section] = []
    
    func setSections(_ sections: [Section]) {
        _sectionModels = sections
    }
    
    func sectionsCount() -> Int {
        return _sectionModels.count
    }
    func itemsCount(section: Int) -> Int {
        return _sectionModels[section].items.count
    }
    
    subscript(section: Int) -> Section {
        let sectionModel = _sectionModels[section]
        
        return Section(model: sectionModel.model, items: sectionModel.items)
    }
    
    subscript(indexPath: IndexPath) -> Section.Item {
        return _sectionModels[indexPath.section].items[indexPath.row]
    }
    
    // MARK: SectionedViewDataSourceType
    func model(at indexPath: IndexPath) throws -> Any { self[indexPath] }
}

• 該類遵守SectionedViewDataSourceType協(xié)議來規(guī)定如何獲取數(shù)據(jù)
• 該類的本質(zhì)存儲組數(shù)據(jù)數(shù)組，并且定義了一些簡便的函數(shù)來獲取數(shù)據(jù)

定義一個TableViewSectionedDataSource類繼承自SectionedDataSource，遵守UITableViewDataSource、RxTableViewDataSourceType協(xié)議：

class TableViewSectionedDataSource<Section: SectionModelType>: SectionedDataSource<Section>, UITableViewDataSource, RxTableViewDataSourceType {
    
    typealias CellForRow = (TableViewSectionedDataSource<Section>, UITableView, IndexPath) -> UITableViewCell
    typealias TitleForHeader = (TableViewSectionedDataSource<Section>, UITableView, Int) -> String?
    typealias TitleForFooter = (TableViewSectionedDataSource<Section>, UITableView, Int) -> String?
    typealias CanEditRow = (TableViewSectionedDataSource<Section>, UITableView, IndexPath) -> Bool
    typealias CanMoveRow = (TableViewSectionedDataSource<Section>, UITableView, IndexPath) -> Bool
    
    var cellForRow: CellForRow
    var titleForHeader: TitleForHeader
    var canEditRow: CanEditRow
    var canMoveRow: CanMoveRow
    
    init(cellForRow: @escaping CellForRow, titleForHeader: @escaping TitleForHeader = { _,_,_ in nil }, canEditRow: @escaping CanEditRow = { _,_,_ in false }, canMoveRow: @escaping CanMoveRow = { _,_,_ in false }) {
        self.cellForRow = cellForRow
        self.titleForHeader = titleForHeader
        self.canEditRow = canEditRow
        self.canMoveRow = canMoveRow
        
        super.init()
    }
    
    
    // MARK: UITableViewDataSource
    func numberOfSections(in tableView: UITableView) -> Int { sectionsCount() }
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { itemsCount(section: section) }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { cellForRow(self, tableView, indexPath) }
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? { titleForHeader(self, tableView, section) }
    func tableView(_ tableView: UITableView, titleForFooterInSection section: Int) -> String? { nil }
    func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool { canEditRow(self, tableView, indexPath) }
    func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool { canMoveRow(self, tableView, indexPath) }
    
    // MArK: RxTableViewDataSourceType
    typealias Element = [Section]
    func tableView(_ tableView: UITableView, observedEvent: Event<TableViewSectionedDataSource<Section>.Element>) {
        Binder(self) { (dataSource, element: Element) in
            dataSource.setSections(element)
            tableView.reloadData()
        }.on(observedEvent)
    }
}

• 類繼承SectionedDataSource是達到對原數(shù)據(jù)的取用
• 遵守UITableViewDataSource協(xié)議為UITableview提供數(shù)據(jù)
• 遵守RxTableViewDataSourceType協(xié)議實現(xiàn)對UITableview的datasource代理所需數(shù)據(jù)存儲，并刷新列表
• cellForRow、titleForHeader、canEditRow、canMoveRow這幾個屬性分別存儲將原數(shù)據(jù)轉(zhuǎn)化為UITableViewDataSource協(xié)議所需要數(shù)據(jù)的閉包，既是行的cell、組頭的標題、行能否編輯、行能否移動

多組數(shù)據(jù)綁定

新建控制器，構建一個UITableview作為屬性tableView。

定義SectionModel遵守SectionModelType表示組數(shù)據(jù)：

struct SectionModel<SectionType, ItemType>: SectionModelType {
    typealias Section = SectionType
    typealias Item = ItemType
    
    var model: Section
    var items: [Item]
    
    init(model: Section, items: [Item]) {
        self.model = model
        self.items = items
    }
}

構建數(shù)據(jù)序列綁定到tableView：

let observable = Observable.just([
    SectionModel(model: 1, items: Array(1...10)),
    SectionModel(model: 2, items: Array(1...10)),
    SectionModel(model: 3, items: Array(1...10)),
    SectionModel(model: 4, items: Array(1...10)),
    SectionModel(model: 5, items: Array(1...10)),
    SectionModel(model: 6, items: Array(1...10)),
    SectionModel(model: 7, items: Array(1...10)),
    SectionModel(model: 8, items: Array(1...10)),
    SectionModel(model: 9, items: Array(1...10)),
    SectionModel(model: 10, items: Array(1...10))
])
let dataSource = TableViewSectionedDataSource<SectionModel<Int, Int>>(cellForRow: { (dataSource, tableView, indexPath) -> UITableViewCell in
        let cell = CommonCell.cellFor(tableView: tableView)

        let item = dataSource[indexPath]
        cell.textLabel?.text = "我是(\(indexPath.section), \(indexPath.row)), \(item)"

        return cell
    }, titleForHeader: { "第\($2)組我是\($0[$2].model)" })
observable.bind(to: tableView.rx.items(dataSource: dataSource))
        .disposed(by: bag)

可編輯的UITableView綁定

新建一個控制器，構建一個UITableview作為屬性tableView。

在導航欄右側設置編輯item:

        self.navigationItem.rightBarButtonItem = self.editButtonItem
        self.navigationItem.rightBarButtonItem?.title = "編輯"

重寫控制器的setEditing函數(shù)來編輯UITableview：

    override func setEditing(_ editing: Bool, animated: Bool) {
        super.setEditing(editing, animated: animated)
        
        tableView.isEditing = editing
        navigationItem.rightBarButtonItem?.title = editing ? "完成" : "編輯"
    }

這個示例稍微復雜，數(shù)據(jù)是從網(wǎng)絡獲得，首先定義數(shù)據(jù)模型與網(wǎng)絡請求工具：

struct User: CustomStringConvertible {
    var firstName: String
    var lastName: String
    var imageURL: String
    
    var description: String {
        return "\(firstName) \(lastName)"
    }
}
class UserAPI {
    class func getUsers(count: Int) -> Observable<[User]> {
        let url = URL(string: "http://api.randomuser.me/?results=\(count)")!
        return URLSession.shared.rx.json(url: url).map { (json) -> [User] in
            guard let json = json as? [String: AnyObject] else {
                fatalError()
            }
            
            guard let results = json["results"] as? [[String: AnyObject]] else {
                fatalError()
            }
            
            return results.map { (info) -> User in
                let name = info["name"] as? [String: String]
                let picture = info["picture"] as? [String: String]
                
                guard let firstName = name?["first"], let lastName = name?["last"], let imageURL = picture?["large"] else {
                    fatalError()
                }
                return User(firstName: firstName, lastName: lastName, imageURL: imageURL)
            }
        }.share(replay: 1)
    }
}

定義枚舉EditingTableViewCommand表示對UITableView的操作：

enum EditingTableViewCommand {
    case addUsers(users: [User], to: IndexPath)
    case moveUser(from: IndexPath, to: IndexPath)
    case deleteUser(indexPath: IndexPath)
}

定義EditingTabelViewViewModel處理UI邏輯：

struct EditingTabelViewViewModel {
    static let initalSections: [SectionModel<String, User>] = [
        SectionModel<String, User>(model: "Favorite Users", items: [
            User(firstName: "Super", lastName: "Man", imageURL: "http://nerdreactor.com/wp-content/uploads/2015/02/Superman1.jpg"),
            User(firstName: "Wat", lastName: "Man", imageURL: "http://www.iri.upc.edu/files/project/98/main.GIF")]),
        SectionModel<String, User>(model: "Normal Users", items: [User]())
    ]
    private let activity = ActivityIndicator()
    
    let sections: Driver<[SectionModel<String, User>]>
    let loading: Driver<Bool>
    
    static func excuteCommand(sections: [SectionModel<String, User>], command: EditingTableViewCommand) -> [SectionModel<String, User>] {
        var result = sections
        switch command {
        case let .addUsers(users, to):
            result[to.section].items.insert(contentsOf: users, at: to.row)
        case let .moveUser(from, to):
            let user = sections[from.section].items[from.row]
            result[from.section].items.remove(at: from.row)
            result[to.section].items.insert(user, at: to.row)
        case let .deleteUser(indexPath):
            result[indexPath.section].items.remove(at: indexPath.row)
        }
        return result
    }
    
    init(itemDelete: RxCocoa.ControlEvent<IndexPath>, itemMoved: RxCocoa.ControlEvent<RxCocoa.ItemMovedEvent>) {
        self.loading = activity.asDriver(onErrorJustReturn: false)
        let add = UserAPI.getUsers(count: 30)
            .map { EditingTableViewCommand.addUsers(users: $0, to: IndexPath(row: 0, section: 1)) }
            .trackActivity(activity)
        
        sections = Observable.deferred {
            let delete = itemDelete.map { EditingTableViewCommand.deleteUser(indexPath: $0) }
            let move = itemMoved.map(EditingTableViewCommand.moveUser)
            return Observable.merge(add, delete, move)
                .scan(EditingTabelViewViewModel.initalSections, accumulator: EditingTabelViewViewModel.excuteCommand(sections:command:))
        }.startWith(EditingTabelViewViewModel.initalSections)
        .asDriver(onErrorJustReturn: EditingTabelViewViewModel.initalSections)
    }
}

• 類型屬性initalSections存儲初始數(shù)據(jù)，私有屬性activity用來記錄網(wǎng)絡活動狀態(tài)序列，屬性sections為UITableView數(shù)據(jù)序列，屬性loading為網(wǎng)絡加載狀態(tài)序列
• 類函數(shù)excuteCommand根據(jù)對UITableview的操作EditingTableViewCommand處理數(shù)據(jù)
• 初始化時用私有屬性activity轉(zhuǎn)化為Driver作為loading屬性
• 初始化時使用UserAPI類的getUsers類型函數(shù)得到一個獲取數(shù)據(jù)的序列，然后使用map操作符轉(zhuǎn)化為EditingTableViewCommand操作的序列記為add
• 初始化時將參數(shù)刪除和移動UITableView行的序列轉(zhuǎn)化為EditingTableViewCommand操作的序列分別記為delete、move
• 初始化時將add、delete、move這三個序列使用merge操作符合并為一個序列，然后使用scan操作符掃描序列將類型屬性initalSections作為初始數(shù)據(jù)、類型函數(shù)excuteCommand作為轉(zhuǎn)換函數(shù)處理成一個元素為[SectionModel<String, User>]類型的序列，最后再使用startWith和asDriver操作符設置初始元素并轉(zhuǎn)換為Driver類型的序列

UITableVIew數(shù)據(jù)復雜綁定實現(xiàn)方式并沒有變化跟簡單綁定是一樣的，無非就是在對UITableview進行操作時相應處理需要綁定到UITableview上的原數(shù)據(jù)如EditingTabelViewViewModel中的excuteCommand函數(shù)，并且在構建TableViewSectionedDataSource時多提供一些canEditRow，canMoveRow等閉包為UITableViewDataSource協(xié)議中定義的函數(shù)提供數(shù)據(jù)支持。

在控制器中構建一個懶加載屬性dataSource提供Cell生成、組頭部標題、是否可以編輯、是否可以移動等閉包：

    lazy var dataSource: TableViewSectionedDataSource<SectionModel<String, User>> = { TableViewSectionedDataSource<SectionModel<String, User>>(cellForRow: { ds, tv, indexPath in
        let cell = CommonCell.cellFor(tableView: tv)
        cell.accessoryType = UITableViewCell.AccessoryType.disclosureIndicator
        cell.textLabel?.text = ds[indexPath].firstName + " " + ds[indexPath].lastName
        
        return cell
    }, titleForHeader: { "\($0[$2].model)>\($0[$2].items)" }, canEditRow: { _,_,_ in true }, canMoveRow: { _,_,_ in true }) }()

擴展Reactive用來綁定加載動畫：

extension Reactive where Base: UIViewController & NVActivityIndicatorViewable {
    var animating: Binder<Bool> {
        return Binder(base) { (t, v) in
            if v != t.isAnimating {
                if v {
                    t.startAnimating()
                } else {
                    t.stopAnimating()
                }
            }
            
            UIApplication.shared.isNetworkActivityIndicatorVisible = v
        }
    }
}

最后構建EditingTabelViewViewModel，進行數(shù)據(jù)綁定：

let viewModel: EditingTabelViewViewModel = EditingTabelViewViewModel(itemDelete: tableView.rx.itemDeleted, itemMoved: tableView.rx.itemMoved)

viewModel.loading
    .drive(self.rx.animating)
    .disposed(by: bag)

viewModel.sections
    .drive(tableView.rx.items(dataSource: dataSource))
    .disposed(by: bag)

tableView.rx
    .modelSelected(User.self)
    .subscribe(onNext: { [weak self] (user) in
        let viewController = UIStoryboard(name: "EditingTableView", bundle: Bundle.main).instantiateViewController(withIdentifier: "DetailViewController") as! DetailViewController
        viewController.user = user
        self?.navigationController?.pushViewController(viewController, animated: true)
    }).disposed(by: bag)

tableView.rx
    .itemSelected
    .subscribe(onNext: { [weak self] in self!.tableView.deselectRow(at: $0, animated: true) })
    .disposed(by: bag)

擴展

參考UIPickerView的Rx實現(xiàn)，其實還可以定義TableViewSectionedDataSource的子類，讓其遵守UITableviewDelegate協(xié)議，進而可以實現(xiàn)對UITableview的行高、組頭部高等進行綁定。