swift - 使用调度组时关闭丢失

Question

调度代码未调用。当我调用 reLog() 方法时，它没有执行 DispatchQueue.main.async block 中编写的代码。

       func reLog() -> Bool {
            var isVerified = false
            let group = DispatchGroup()
            group.enter()
            DispatchQueue.global(qos: .default).async {
                    self.login({ () -> Void in
                        isVerified = true
                        group.leave()
                    }, fail: { (failureDict) -> Void in
                        group.leave()
                    })
                }
            group.wait() 
            return isVerified
        }


        func login(_ success : (()-> Void), fail : (()-> Void)){
             let session = URLSession(configuration: .default, delegate: self, delegateQueue: nil)
             let task = session.dataTask(with: urlRequest){
                (data, response, error) -> Void in
                  DispatchQueue.main.async(execute: { () -> Void in
                       print("Testing")   // This closure not calling
                  })
             })
             task.resume()
        }

现在这是我的要求。我需要实现它，因为我需要服务器响应才能继续循环。

for i in strings {
     let isLogged = relog()
     if isLogged {
        print("Successful")
    }
}

Answer 1

你需要在里面login

task.resume()

---

替换

group.wait() 
return isVerified

与

group.notify(queue:.main) {
  completion(isVerified)
}

和

func reLog(completion:@escaping(Bool) -> ())

---

编辑

func reLog(completion:@escaping(Bool) -> ())
            var isVerified = false
            let group = DispatchGroup()
            group.enter()
            DispatchQueue.global(qos: .default).async {
                    self.login({ () -> Void in
                        isVerified = true
                        group.leave()
                    }, fail: { (failureDict) -> Void in
                        group.leave()
                    })
                }
        group.notify(queue:.main) {
          completion(isVerified)
        } 
 }

打电话

 reLog {  isVerified in
   print(isVerified)
 }