如何知道多个网络通话何时结束，才能完成通话

我建议使用调度组：

func resetDevice(completion: () -> ()) {    let dispatchGroup = DispatchGroup()    for device in devices {        dispatchGroup.enter()        device.isValid = 0        DeviceManager.instance.updateDevice(device).call { response in print("device reset") dispatchGroup.leave()        }    }    dispatchGroup.notify(queue: DispatchQueue.main) {        // Some pre to execute when all devices have been reset    }}

每个设备都立即进入该组，但直到收到响应后才离开该组。在所有对象都离开组之前，不会调用最后的notify块。