RXSwift + Moya + 错误处理 + 刷新按钮

Question

我正在尝试设置一个在按下按钮后刷新用户数据的表视图。RXSwift 用于整个事件链。莫亚用于路由。

我正在尝试使用 Moya 给出的标准错误处理，即：

provider.rx.request(.userProfile("ashfurrow")).subscribe { event in
switch event {
case let .success(response):
image = UIImage(data: response.data)
case let .error(error):
print(error)
}
}

我能够使其工作的唯一方法是使用内部订阅方法。请参阅下面的代码。谁能想到一种不需要内部订阅的方法？这似乎有点笨拙。

class ViewController: UIViewController {
@IBOutlet weak var refreshBtn: UIButton!
@IBOutlet weak var tableView: UITableView!
let provider = MoyaProvider<MyAPI>()
let disposeBag = DisposeBag()
var latestUsers = Variable<[User]>([])
override func viewDidLoad() {
super.viewDidLoad()
setupObservableBtnRefreshWithDataFetch()
bindDataToTableView()
}
func setupObservableBtnRefreshWithDataFetch() {
let refreshStream = refreshBtn.rx.tap.startWith(())
let responseStream = refreshStream.flatMapLatest { _ -> SharedSequence<DriverSharingStrategy, [User]> in
let request = self.provider.rx.request(.showUsers)
// Inner Subscribe here, to be able to use the standard Moya subscribe methods for error handling
request.subscribe { event in
switch event {
case .success(let user):
print("Success")
case .error(let error):
print("Error occurred: (error.localizedDescription)")
}
}
return request
.filterSuccessfulStatusCodes()
.map([User].self)
.asDriver(onErrorJustReturn: [])
}
let nilOnRefreshTapStream: Observable<[User]> = refreshBtn.rx.tap.map { _ in return [] }
let tableDisplayStream = Observable.of(responseStream, nilOnRefreshTapStream)
.merge()
.startWith([])
tableDisplayStream
.subscribe { event in
switch event {
case .next(let users):
print("Users are:")
print(users)
self.latestUsers.value = users
break
case .completed:
break
case .error(let error):
print("Error occurred: (error.localizedDescription)")
break
}
}
.disposed(by: self.disposeBag)
}
func bindDataToTableView() {
latestUsers.asObservable()
.bind(to: tableView.rx.items(cellIdentifier: "cell", cellType: UITableViewCell.self)) { (_, model: User, cell: UITableViewCell) in
cell.textLabel?.text = model.login
}
.disposed(by: disposeBag)
}
}      
class User: Decodable {
var name: String?
var mobile: Int?
var userRequestedTime: String?
var login: String?
init(name: String, mobile: Int, login: String = "") {
self.name = name
self.mobile = mobile
self.login = login
}
}

Answer 1

我调查了Moya，了解到它是网络操作的包装器。

目前还不完全清楚内部订阅的目的是什么 - 根据我的理解，它会触发一个相同但独立的网络请求，这应该不会影响另一个请求订阅。 似乎刷新按钮点击在tableDisplayStream中发出两个元素(来自responseStream(来自refreshStream(和nilOnRefreshTapStream(。

请注意，变量已弃用。就个人而言，我也更喜欢.debug().subscribe()在订阅关闭中手动打印事件。

基于此，我将按如下方式编写代码。我还没有测试过。希望对您有所帮助！

class ViewController: UIViewController {
// ...
private let provider = MoyaProvider<MyAPI>()
private let disposeBag = DisposeBag()
/// Variable<T> is deprecated; use BehaviorRelay instead
private let users = BehaviorRelay<[User]>(value: [])
private func setupObservableBtnRefreshWithDataFetch() {
refreshBtn.rx.tap
.startWith(()) // trigger initial load
.flatMapLatest { _ in 
self.provider.rx.request(.showUsers)
.debug("moya request")
.filterSuccessfulStatusCodes()
.map([User].self)
.asDriver(onErrorJustReturn: []) // don't let the error escape
} 
.drive(users)
.disposed(by: disposeBag)
}
private func bindDataToTableView() {
users
.asDriver()
.debug("driving table view ")
.drive(tableView.rx.items /* ... */)
.disposed(by: disposeBag)
}
}