我正在构建一个watchOS应用，该应用需要定期从同伴的iPhone应用中请求信息以刷新并发症。
为了实现这一点，我有一个定期运行的WKApplicationRefreshBackgroundTask。它使用sendMessage(_:replyHandler:errorHandler:)中的WatchConnectivity从iPhone应用程序请求信息，处理回复并更新并发症。
[在大多数情况下，这对于许多用户来说都是可靠的，但是，我发现Apple Watch在与sendMessage(_:replyHandler:errorHandler:)有关的Xcode中崩溃，我担心这会导致用户错过并发症的更新。一些用户一直抱怨并发症没有更新，所以我试图确定是否有超出常规限制的问题，这些问题可以在watchOS中刷新的频率。
有人对我如何解决此问题有任何建议吗？或者，您对我可以如何更好地解决导致崩溃的问题并找出预防方法的想法吗？
[我在底部提供了其中一个崩溃的完整示例，以及处理后台任务的代码以及处理从配对的iPhone发送和接收值的代码。
我永远都不会在没有ReplyHandler的情况下发送消息，因此在iPhone上使用others have seen problems because the delegate method for a message without a handler was not implemented时，我认为这不是问题所在。为了安全起见，我在iPhone上将委托方法实现为不执行任何操作的空方法。
2020年1月30日更新：一位朋友建议说，问题可能出在任务仍在进行中时，该任务被10秒计时器标记为已完成，当待处理的事情完成但未完成时，就会导致内存问题。确保可以采取什么措施。也许这是这里问题的核心？
这是我的ExtensionDelegate的后台刷新代码：
func handle(_ backgroundTasks: Set<WKRefreshBackgroundTask>) {
for task in backgroundTasks {
switch task {
case let backgroundTask as WKApplicationRefreshBackgroundTask:
// set a timer in case it doesn't complete
// the maximum allowed is 15 seconds, and then it crashes, so schedule the new task and mark complete after 10
var timeoutTimer: Timer? = Timer.scheduledTimer(withTimeInterval: 10, repeats: false) { (timer) in
self.scheduleBackgroundRefresh()
backgroundTask.setTaskCompletedWithSnapshot(false)
}
// schedule the next refresh now in case the request crashes
scheduleBackgroundRefresh()
WatchConnectivityManager.shared.requestDataFromPhone()
ComplicationManager.shared.reloadComplication()
// as long as the expiration timer is valid, cancel the timer and set the task complete
// otherwise, we'll assume the timer has fired and the task has been marked complete already
// if it's marked complete again, that's a crash
if let timerValid = timeoutTimer?.isValid, timerValid == true {
timeoutTimer?.invalidate()
timeoutTimer = nil
backgroundTask.setTaskCompletedWithSnapshot(true)
}
default:
// make sure to complete unhandled task types
task.setTaskCompletedWithSnapshot(false)
}
}
}
private func scheduleBackgroundRefresh() {
let fiveMinutesFromNow: Date = Date(timeIntervalSinceNow: 5 * 60)
WKExtension.shared().scheduleBackgroundRefresh(withPreferredDate: fiveMinutesFromNow,
userInfo: nil) { (error) in
if let error = error {
fatalError("\(error)")
}
}
}
这里是WatchConnectivityManager：
import Foundation
import WatchKit
import WatchConnectivity
class WatchConnectivityManager: NSObject {
static let shared = WatchConnectivityManager()
let session = WCSession.default
private let receivedMessageQueue: OperationQueue = {
let queue = OperationQueue()
queue.maxConcurrentOperationCount = 1
return queue
}()
private func process(messageOrUserInfo: [String : Any]) {
receivedMessageQueue.addOperation {
if let recievedValue = messageOrUserInfo["ValueFromPhone"] as? Int {
DispatchQueue.main.async {
ViewModel.shared.valueFromPhone = recievedValue
}
}
}
}
func requestDataFromPhone() {
if session.activationState == .activated {
let message: [String : Any] = ["Request" : true]
let replyHandler: (([String : Any]) -> Void) = { reply in
self.process(messageOrUserInfo: reply)
}
let errorHandler: ((Error) -> Void) = { error in
}
if session.isReachable {
session.sendMessage(message,
replyHandler: replyHandler,
errorHandler: errorHandler)
}
// send a request to the iPhone as a UserInfo in case the message fails
session.transferUserInfo(message)
}
}
}
extension WatchConnectivityManager: WCSessionDelegate {
func session(_ session: WCSession,
activationDidCompleteWith activationState: WCSessionActivationState,
error: Error?) {
if activationState == .activated {
requestDataFromPhone()
}
}
func session(_ session: WCSession,
didReceiveUserInfo userInfo: [String : Any])
{
process(messageOrUserInfo: userInfo)
}
}
示例崩溃：
Hardware Model: Watch3,4
AppVariant: 1:Watch3,4:6
Code Type: ARM (Native)
Role: Non UI
Parent Process: launchd [1]
OS Version: Watch OS 6.1.1 (17S449)
Release Type: User
Baseband Version: n/a
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x00000004
VM Region Info: 0x4 is not in any region. Bytes before following region: 638972
REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL
UNUSED SPACE AT START
--->
__TEXT 0009c000-000ac000 [ 64K] r-x/r-x SM=COW ...x/App Name
Termination Signal: Segmentation fault: 11
Termination Reason: Namespace SIGNAL, Code 0xb
Terminating Process: exc handler [377]
Triggered by Thread: 9
Thread 0 name:
Thread 0:
0 libsystem_kernel.dylib 0x4381f864 semaphore_wait_trap + 8
1 libdispatch.dylib 0x436dac26 _dispatch_sema4_wait + 12 (lock.c:139)
2 libdispatch.dylib 0x436db09a _dispatch_semaphore_wait_slow + 104 (semaphore.c:132)
3 FrontBoardServices 0x46de503e -[FBSSceneSnapshotRequestHandle performRequestForScene:] + 408 (FBSSceneSnapshotRequestHandle.m:67)
4 FrontBoardServices 0x46de96ac -[FBSSceneSnapshotAction snapshotRequest:performWithContext:] + 218 (FBSSceneSnapshotAction.m:168)
5 FrontBoardServices 0x46da4320 -[FBSSceneSnapshotRequest performSnapshotWithContext:] + 292 (FBSSceneSnapshotRequest.m:65)
6 UIKitCore 0x5ba6a000 __65-[UIApplication _performSnapshotsWithAction:forScene:completion:]_block_invoke_3 + 168 (UIApplication.m:7655)
7 FrontBoardServices 0x46de9568 -[FBSSceneSnapshotAction _executeNextRequest] + 244 (FBSSceneSnapshotAction.m:135)
8 FrontBoardServices 0x46de91e0 -[FBSSceneSnapshotAction executeRequestsWithHandler:completionHandler:expirationHandler:] + 244 (FBSSceneSnapshotAction.m:87)
9 UIKitCore 0x5ba69f20 __65-[UIApplication _performSnapshotsWithAction:forScene:completion:]_block_invoke_2 + 238 (UIApplication.m:7650)
10 UIKitCore 0x5ba69696 -[UIApplication _beginSnapshotSessionForScene:withSnapshotBlock:] + 772 (UIApplication.m:7582)
11 UIKitCore 0x5ba69e16 __65-[UIApplication _performSnapshotsWithAction:forScene:completion:]_block_invoke + 112 (UIApplication.m:7648)
12 UIKitCore 0x5b2c1110 -[UIScene _enableOverrideSettingsForActions:] + 40 (UIScene.m:1206)
13 UIKitCore 0x5b2c1330 -[UIScene _performSystemSnapshotWithActions:] + 112 (UIScene.m:1230)
14 UIKitCore 0x5ba69b90 -[UIApplication _performSnapshotsWithAction:forScene:completion:] + 382 (UIApplication.m:7647)
15 UIKitCore 0x5be89586 __98-[_UISceneSnapshotBSActionsHandler _respondToActions:forFBSScene:inUIScene:fromTransitionCont... + 146 (_UISceneSnapshotBSActionsHandler.m:54)
16 UIKitCore 0x5ba68fd4 _runAfterCACommitDeferredBlocks + 274 (UIApplication.m:3038)
17 UIKitCore 0x5ba5b3da _cleanUpAfterCAFlushAndRunDeferredBlocks + 198 (UIApplication.m:3016)
18 UIKitCore 0x5ba82702 _afterCACommitHandler + 56 (UIApplication.m:3068)
19 CoreFoundation 0x43b63644 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 18 (CFRunLoop.c:1758)
20 CoreFoundation 0x43b5f43c __CFRunLoopDoObservers + 350 (CFRunLoop.c:1868)
21 CoreFoundation 0x43b5f956 __CFRunLoopRun + 1150 (CFRunLoop.c:2910)
22 CoreFoundation 0x43b5f23a CFRunLoopRunSpecific + 370 (CFRunLoop.c:3192)
23 GraphicsServices 0x46973cd0 GSEventRunModal + 96 (GSEvent.c:2246)
24 UIKitCore 0x5ba61580 UIApplicationMain + 1730 (UIApplication.m:4773)
25 libxpc.dylib 0x438fbcf0 _xpc_objc_main.cold.3 + 152
26 libxpc.dylib 0x438eca34 _xpc_objc_main + 184 (main.m:126)
27 libxpc.dylib 0x438ee934 xpc_main + 110 (init.c:1568)
28 Foundation 0x443f3156 -[NSXPCListener resume] + 172 (NSXPCListener.m:276)
29 PlugInKit 0x4b58b26c -[PKService run] + 384 (PKService.m:165)
30 WatchKit 0x52e9dafe WKExtensionMain + 62 (main.m:19)
31 libdyld.dylib 0x43715e82 start + 2
Thread 1 name:
Thread 1:
0 libsystem_kernel.dylib 0x4381f814 mach_msg_trap + 20
1 libsystem_kernel.dylib 0x4381eece mach_msg + 42 (mach_msg.c:103)
2 CoreFoundation 0x43b63946 __CFRunLoopServiceMachPort + 152 (CFRunLoop.c:2575)
3 CoreFoundation 0x43b5f9de __CFRunLoopRun + 1286 (CFRunLoop.c:2931)
4 CoreFoundation 0x43b5f23a CFRunLoopRunSpecific + 370 (CFRunLoop.c:3192)
5 Foundation 0x443bf398 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 180 (NSRunLoop.m:374)
6 Foundation 0x443bf2b4 -[NSRunLoop(NSRunLoop) runUntilDate:] + 76 (NSRunLoop.m:421)
7 UIKitCore 0x5badf012 -[UIEventFetcher threadMain] + 140 (UIEventFetcher.m:637)
8 Foundation 0x444c1b60 __NSThread__start__ + 708 (NSThread.m:724)
9 libsystem_pthread.dylib 0x438ad1ac _pthread_start + 130 (pthread.c:896)
10 libsystem_pthread.dylib 0x438b3f28 thread_start + 20
Thread 2 name:
Thread 2:
0 libsystem_kernel.dylib 0x43836d04 __psynch_cvwait + 24
1 libsystem_pthread.dylib 0x438b02c2 _pthread_cond_wait + 496 (pthread_cond.c:591)
2 libsystem_pthread.dylib 0x438aca4a pthread_cond_wait + 38 (pthread_cancelable.c:558)
3 Foundation 0x444381f0 -[NSOperation waitUntilFinished] + 446 (NSOperation.m:737)
4 Foundation 0x444a5302 __NSOPERATIONQUEUE_IS_WAITING_ON_AN_OPERATION__ + 22 (NSOperation.m:2610)
5 Foundation 0x444222ee -[NSOperationQueue addOperations:waitUntilFinished:] + 128 (NSOperation.m:2618)
6 WatchConnectivity 0x53f9871e __47-[WCSession handleUserInfoResultWithPairingID:]_block_invoke.491 + 540 (WCSession.m:1440)
7 WatchConnectivity 0x53fa5608 -[WCFileStorage enumerateUserInfoResultsWithBlock:] + 1564 (WCFileStorage.m:505)
8 WatchConnectivity 0x53f984ca __47-[WCSession handleUserInfoResultWithPairingID:]_block_invoke_2 + 284 (WCSession.m:1430)
9 Foundation 0x444a4794 __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 10 (NSOperation.m:1541)
10 Foundation 0x443d2f7a -[NSBlockOperation main] + 74 (NSOperation.m:1560)
11 Foundation 0x444a63e2 __NSOPERATION_IS_INVOKING_MAIN__ + 22 (NSOperation.m:2184)
12 Foundation 0x443d2b96 -[NSOperation start] + 578 (NSOperation.m:2201)
13 Foundation 0x444a6b7c __NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 22 (NSOperation.m:2215)
14 Foundation 0x444a6798 __NSOQSchedule_f + 134 (NSOperation.m:2226)
15 libdispatch.dylib 0x436d9846 _dispatch_call_block_and_release + 10 (init.c:1408)
16 libdispatch.dylib 0x436da8b8 _dispatch_client_callout + 6 (object.m:495)
17 libdispatch.dylib 0x436dc6f8 _dispatch_continuation_pop + 330 (inline_internal.h:2484)
18 libdispatch.dylib 0x436dc08c _dispatch_async_redirect_invoke + 520 (queue.c:803)
19 libdispatch.dylib 0x436e6eac _dispatch_root_queue_drain + 540 (inline_internal.h:2525)
20 libdispatch.dylib 0x436e73e0 _dispatch_worker_thread2 + 98 (queue.c:6628)
21 libsystem_pthread.dylib 0x438aecd2 _pthread_wqthread + 158 (pthread.c:2364)
22 libsystem_pthread.dylib 0x438b3f10 start_wqthread + 20
Thread 3:
0 libsystem_pthread.dylib 0x438b3efc start_wqthread + 0
Thread 4:
0 libsystem_pthread.dylib 0x438b3efc start_wqthread + 0
Thread 5:
0 libsystem_pthread.dylib 0x438b3efc start_wqthread + 0
Thread 6 name:
Thread 6:
0 libsystem_kernel.dylib 0x43838c6c kevent_qos + 24
1 libdispatch.dylib 0x436f2b74 _dispatch_kq_poll + 204 (event_kevent.c:736)
2 libdispatch.dylib 0x436f280a _dispatch_kq_drain + 96 (event_kevent.c:809)
3 libdispatch.dylib 0x436f2196 _dispatch_event_loop_poke + 162 (event_kevent.c:1918)
4 libdispatch.dylib 0x436e32b8 _dispatch_mgr_queue_push + 110 (queue.c:5857)
5 WatchConnectivity 0x53f9aa26 -[WCSession createAndStartTimerOnWorkQueueWithHandler:] + 150 (WCSession.m:1803)
6 WatchConnectivity 0x53f90790 -[WCSession onqueue_sendMessageData:replyHandler:errorHandler:dictionaryMessage:] + 382 (WCSession.m:674)
7 WatchConnectivity 0x53f901da __51-[WCSession sendMessage:replyHandler:errorHandler:]_block_invoke.256 + 190 (WCSession.m:630)
8 Foundation 0x444a4794 __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 10 (NSOperation.m:1541)
9 Foundation 0x443d2f7a -[NSBlockOperation main] + 74 (NSOperation.m:1560)
10 Foundation 0x444a63e2 __NSOPERATION_IS_INVOKING_MAIN__ + 22 (NSOperation.m:2184)
11 Foundation 0x443d2b96 -[NSOperation start] + 578 (NSOperation.m:2201)
12 Foundation 0x444a6b7c __NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 22 (NSOperation.m:2215)
13 Foundation 0x444a6798 __NSOQSchedule_f + 134 (NSOperation.m:2226)
14 libdispatch.dylib 0x436e4c02 _dispatch_block_async_invoke2 + 80 (queue.c:525)
15 libdispatch.dylib 0x436da8b8 _dispatch_client_callout + 6 (object.m:495)
16 libdispatch.dylib 0x436dc6f8 _dispatch_continuation_pop + 330 (inline_internal.h:2484)
17 libdispatch.dylib 0x436dc08c _dispatch_async_redirect_invoke + 520 (queue.c:803)
18 libdispatch.dylib 0x436e6eac _dispatch_root_queue_drain + 540 (inline_internal.h:2525)
19 libdispatch.dylib 0x436e73e0 _dispatch_worker_thread2 + 98 (queue.c:6628)
20 libsystem_pthread.dylib 0x438aecd2 _pthread_wqthread + 158 (pthread.c:2364)
21 libsystem_pthread.dylib 0x438b3f10 start_wqthread + 20
Thread 7:
0 libsystem_pthread.dylib 0x438b3efc start_wqthread + 0
Thread 8:
0 libsystem_pthread.dylib 0x438b3efc start_wqthread + 0
Thread 9 name:
Thread 9 Crashed:
0 libdispatch.dylib 0x436eacec dispatch_channel_cancel + 6 (source.c:1020)
1 WatchConnectivity 0x53f909c6 __81-[WCSession onqueue_sendMessageData:replyHandler:errorHandler:dictionaryMessage:]_block_invoke + 42 (WCSession.m:675)
2 libdispatch.dylib 0x436da8b8 _dispatch_client_callout + 6 (object.m:495)
3 libdispatch.dylib 0x436dc6f8 _dispatch_continuation_pop + 330 (inline_internal.h:2484)
4 libdispatch.dylib 0x436ea81e _dispatch_source_invoke + 1758 (source.c:568)
5 libdispatch.dylib 0x436e6eac _dispatch_root_queue_drain + 540 (inline_internal.h:2525)
6 libdispatch.dylib 0x436e73e0 _dispatch_worker_thread2 + 98 (queue.c:6628)
7 libsystem_pthread.dylib 0x438aecd2 _pthread_wqthread + 158 (pthread.c:2364)
8 libsystem_pthread.dylib 0x438b3f10 start_wqthread + 20
Thread 10:
0 libsystem_pthread.dylib 0x438b3efc start_wqthread + 0
Thread 11:
0 libsystem_pthread.dylib 0x438b3efc start_wqthread + 0
Thread 9 crashed with ARM Thread State (32-bit):
r0: 0x00000000 r1: 0x80000000 r2: 0x00000001 r3: 0x7fffffff
r4: 0x16548f40 r5: 0x00000000 r6: 0x00000110 r7: 0x3f057e58
r8: 0x00000000 r9: 0x00000000 r10: 0x00000000 r11: 0x00401600
ip: 0x66e39628 sp: 0x3f057e30 lr: 0x53f909c7 pc: 0x436eacec
cpsr: 0x80000030
我认为您的朋友是对的：当您将后台任务设置为完成时，系统将挂起您的应用程序，请参见here。并且系统可以清除挂起的应用程序而不会发出警告，请参阅here。因此，如果发生这种情况，则无法调用replyHandler或errorHandler，并且应用程序崩溃。因此，您不能依靠sendMessage来唤醒iOS应用程序并及时调用replyHandler。我建议您在iOS上初始化并发症数据的传输。要定期执行此操作，可以使用silent push notifications来唤醒您的iOS应用，然后使用transferCurrentComplicationUserInfo(_:)发送新的并发症数据，请参阅here。即使您的手表应用未运行，也会收到此userInfo，并且可以根据需要更新并发症数据。