使用WatchConnectivity获取核心数据获取请求

Question

我目前正在尝试从我的ios应用程序获取CoreData数据到watchOS扩展。我正在使用WatchConnectivity Framework通过sendMessage(_ message: [String : Any], replyHandler: (([String : Any]) -> Void)?, errorHandler: ((Error) -> Void)? = nil)函数获取字典。基本连接正常。 iOS应用程序是可以访问的，如果我尝试回复示例字典，一切正常。

到目前为止一切都很好，但是当我开始在后台的iOS应用程序上执行获取请求时，Watch App从不接收数据。过了一会儿我才得到这个错误：Error while requesting data from iPhone: Error Domain=WCErrorDomain Code=7012 "Message reply took too long." UserInfo={NSLocalizedFailureReason=Reply timeout occurred., NSLocalizedDescription=Message reply took too long.}

如果我在iPhone上打开iOS应用程序并重新启动Watch App，则回复处理程序将获得结果。但是迫使用户在iPhone上主动打开iOS应用程序是没用的。

有人可以解释为什么会这样吗？什么是正确的方法呢？自WatchOS 2以来，应用程序组似乎已经过时了。我正在使用Swift 4 btw ......

在Apple Watch上：

import WatchConnectivity

class HomeInterfaceController: WKInterfaceController, WCSessionDelegate {

// (…)

func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {

    session.sendMessage(["request": "persons"],
                         replyHandler: { (response) in
                            print("response: (response)")
                         },
                         errorHandler: { (error) in
                            print("Error while requesting data from iPhone: (error)")
    })
}

在iPhone上：

import CoreData
import WatchConnectivity

class ConnectivityHandler: NSObject, WCSessionDelegate {

var personsArray:[Person] = []

// (…)

func session(_ session: WCSession, didReceiveMessage message: [String : Any], replyHandler: @escaping ([String : Any]) -> Void) {

    // only using the next line is working!
    // replyHandler(["data": "test"])

    if message["request"] as? String == "persons" {
        fetchAllPersons()

        var allPersons: [String] = []
        for person in personsArray {
            allPersons.append(person.name!)
        }

        replyHandler(["names": allPersons])
    }
}

// this seems to be never executed (doesn't matter if it's in an extra function or right in the didReceiveMessage func)
func fetchAllPersons() {

    do {
        // Create fetch request.
        let fetchRequest: NSFetchRequest<Person> = Person.fetchRequest()

        // Edit the sort key as appropriate.
        let sortDescriptor = NSSortDescriptor(key: #keyPath(Person.name), ascending: true)
        fetchRequest.sortDescriptors = [sortDescriptor]

        personsArray = try DatabaseController.getContext().fetch(fetchRequest)
    } catch {
        fatalError("Failed to fetch: (error)")
    }
}

Answer 1

另一答案