我想通过点击登录按钮开始登录任务,完成后,获取用户订单列表、送货地址、愿望 list 和其他信息。
startTask 是一个按钮,用户点击它,我将开始这些任务,但是现在如果登录任务失败,用户再次点击 startTask 按钮,我不能再次开始这些任务,为什么?
示例代码
private func test() {
let data = ["fetch order list", "fetch shipping addresses", "fetch wishlist", "fetch other info"]
let fetchInfoTasks = data.map{ asyncTask($0) }.toObservable()
let someTasks = fetchInfoTasks.merge().toArray()
let result = login().flatMapLatest{ _ in someTasks }
startTask
.rx_tap
.flatMapLatest{ result }
.catchError{ error in
.....error......
return Observable.empty()
}
.subscribeNext{ tasks in
.....all completed....
}
.addDisposableTo(disposeBag)
}
private func login()-> Observable<String> {
return Observable.create{ observer in
performClosure(afterDealy: 1, onMainQueue: false) {
if arc4random() % 4 == 0 {
observer.onNext("login finished")
observer.onCompleted()
} else {
observer.onError(NSError(domain: "", code: -1, userInfo: [NSLocalizedDescriptionKey: "some error"]))
}
}
return AnonymousDisposable{}
}
}
private func asyncTask(name: String)-> Observable<String> {
return Observable.create{ observer in
let delay = Double(arc4random() % 6 + 1)
performClosure(afterDealy: delay, onMainQueue: false) {
observer.onNext(name)
observer.onCompleted()
}
return AnonymousDisposable{}
}
}
func performClosure(afterDealy delay: Double, onMainQueue mainQueueOrNot: Bool, action: dispatch_block_t) {
let delayIntervals = Double(NSEC_PER_SEC) * delay
let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delayIntervals))
let queue = mainQueueOrNot ? dispatch_get_main_queue() : dispatch_get_global_queue(QOS_CLASS_UTILITY, 0)
dispatch_after(time, queue, action)
}
最佳答案
一旦发生错误,流就会终止。您不希望这种情况发生在您的按钮级别,因此您必须在更深层次上捕获错误。
例如:
startTask
.rx_tap
.flatMapLatest{
result
.catchError{ error in
.....error......
return Observable.empty()
}
}
.subscribeNext{ tasks in
.....all completed....
}
.addDisposableTo(disposeBag)
通过这种方式,您可以防止实际的 Rx 错误通过 flatMap 冒泡。
如果您需要在出错时执行某些操作,您可能希望将结果包装在某种结果枚举中(推荐 https://github.com/antitypical/Result)。
这方面的一个例子是:
startTask
.rx_tap
.flatMapLatest{
result
.map { Result.Success(result: $0)
.catchError{ error in return Result.Error(error: $0) }
}
.subscribeNext{ result in
switch(result) {
case .Success(let result):
//display happy case
case .Error(let error):
//display sad case
}
.addDisposableTo(disposeBag)
关于swift - RxSwift 异步任务,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37475122/