Singleton Dispatch 不等待其他组

Question

我正在尝试等待来自不同 classes 的所有函数完成将数据附加到数组，然后再继续。

我为 dispath 组创建了一个单例 class。当来自不同 classes 的所有组都离开时，它不会通知 result()，而是单独通知 result()。

class parralelRunner {
    let dispatchGroup = DispatchGroup()

    result(){
        dispatchGroup.notify(queue: .main) {
        print("All functions complete ")
    }
    }
}

class run1 {

    func start(){
        callAPI(){
            filterresult()
        }
    }

    callAPI(completion: (JSON)){
    Alamofire.request("url", headers: headers).responseJSON { response in
        if response.result.isSuccess{
            completion(JSON(response.result.value!))
        }else{
            print("Binance - Couldn't import Request: Please check your internet connection")
        }
    }
    }


    func filterresult(){
    parralelRunner.dispatchGroup.enter()
    for .... {

    }
    parralelRunner.dispatchGroup.leave()
    parralelRunner.result()
    }
}



class run2 {

    func start(){
        callAPI(){
            filterresult()
        }
    }

    callAPI(completion: (JSON)){
    Alamofire.request("url", headers: headers).responseJSON { response in
        if response.result.isSuccess{
            completion(JSON(response.result.value!))
        }else{
            print("Binance - Couldn't import Request: Please check your internet connection")
        }
    }
    }


    func filterresult(){
    parralelRunner.dispatchGroup.enter()
    for .... {

    }
    parralelRunner.dispatchGroup.leave()
    parralelRunner.result()
    }
}

Answer 1

对parralelRunner.result()的调用只能调用一次。并且需要在每个异步进程开始时调用 enter 并在完成时相应调用 leave。

您需要做的第一件事是将 run1 和 run2 重构为如下所示：

class run1 {
    func start(){
        parralelRunner.dispatchGroup.enter()
        callAPI(){ JSON in
            if let JSON = JSON {
                filterresult()
            }
            parralelRunner.dispatchGroup.leave()
        }
    }

    callAPI(completion: (JSON?)){
        Alamofire.request("url", headers: headers).responseJSON { response in
            if response.result.isSuccess{
                completion(JSON(response.result.value!))
            }else{
                print("Binance - Couldn't import Request: Please check your internet connection")
                completion(nil)
            }
        }
    }

    func filterresult() {
        for .... {

        }
    }
}

然后在使用 run1 和 run2 的情况下，您需要像这样的东西：

run1.start()
run2.start()
parralelRunner.result()

Singleton Dispatch 不等待其他组

Singleton Dispatch not waiting for other groups

grand-central-dispatch

swift

alamofire