问题描述
我正面临一个问题，没有任何解决方案(尚未).用户按下主页"按钮后，我正在使用后台任务处理程序来开始某些数据提取.代码类似于:
I'm facing a problem, without any solution (yet). I'm using a background task handler to start some data fetching, after the user press the Home button. The code is something like:
-(void)startRequest {
UIApplication *app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
});
}];
//..
//Fetch data with NSURLRequest / delegate method
//..
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
if ([delegate respondsToSelector:delegateErrorMethod])
[delegate performSelector:delegateErrorMethod];
UIApplication *app = [UIApplication sharedApplication];
if (bgTask != UIBackgroundTaskInvalid) {
dispatch_async(dispatch_get_main_queue(), ^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
});
}
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
if([delegate respondsToSelector:delegateMethod])
[delegate performSelector:delegateMethod withObject:self];
UIApplication *app = [UIApplication sharedApplication];
if (bgTask != UIBackgroundTaskInvalid) {
dispatch_async(dispatch_get_main_queue(), ^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
});
}
}
它很好用，但是有时(没有任何问题或原因，所以这真的是不可预测的)，应用程序崩溃并显示以下崩溃日志:
It works great, but sometimes (without any issue or reason, so it's really unpredictable) the application crash with the following crash log:
Application Specific Information:
MyBackgroundTest[7745] has active assertions beyond permitted time:
{(
<SBProcessAssertion: 0x90e65e0> identifier: UIKitBackgroundCompletionTask process: MyBackgroundTest[7745] permittedBackgroundDuration: 600.000000 reason: finishTask owner pid:7745 preventSuspend preventIdleSleep
)}
Elapsed total CPU time (seconds): 0.010 (user 0.010, system 0.000), 100% CPU
Elapsed application CPU time (seconds): 0.000, 0% CPU
Thread 0:
0 libSystem.B.dylib 0x33b5d268 mach_msg_trap + 20
1 libSystem.B.dylib 0x33b5f354 mach_msg + 44
2 CoreFoundation 0x33a48648 __CFRunLoopServiceMachPort + 88
3 CoreFoundation 0x33a47ed2 __CFRunLoopRun + 350
4 CoreFoundation 0x33a47c80 CFRunLoopRunSpecific + 224
5 CoreFoundation 0x33a47b88 CFRunLoopRunInMode + 52
6 GraphicsServices 0x33b0e4a4 GSEventRunModal + 108
7 GraphicsServices 0x33b0e550 GSEventRun + 56
8 UIKit 0x32099322 -[UIApplication _run] + 406
9 UIKit 0x32096e8c UIApplicationMain + 664
10 MyBackgroundTest 0x00002d64 0x1000 + 7524
11 MyBackgroundTest 0x00002d18 0x1000 + 7448
Thread 1:
0 libSystem.B.dylib 0x33b89974 kevent + 24
1 libSystem.B.dylib 0x33c33704 _dispatch_mgr_invoke + 88
2 libSystem.B.dylib 0x33c33174 _dispatch_queue_invoke + 96
3 libSystem.B.dylib 0x33c32b98 _dispatch_worker_thread2 + 120
4 libSystem.B.dylib 0x33bd724a _pthread_wqthread + 258
5 libSystem.B.dylib 0x33bcf970 start_wqthread + 0
Thread 2:
0 libSystem.B.dylib 0x33b5d268 mach_msg_trap + 20
1 libSystem.B.dylib 0x33b5f354 mach_msg + 44
2 CoreFoundation 0x33a48648 __CFRunLoopServiceMachPort + 88
3 CoreFoundation 0x33a47ed2 __CFRunLoopRun + 350
4 CoreFoundation 0x33a47c80 CFRunLoopRunSpecific + 224
5 CoreFoundation 0x33a47b88 CFRunLoopRunInMode + 52
6 WebCore 0x304df124 RunWebThread(void*) + 332
7 libSystem.B.dylib 0x33bd6886 _pthread_start + 242
8 libSystem.B.dylib 0x33bcba88 thread_start + 0
Thread 3:
0 libSystem.B.dylib 0x33b5d268 mach_msg_trap + 20
1 libSystem.B.dylib 0x33b5f354 mach_msg + 44
2 CoreFoundation 0x33a48648 __CFRunLoopServiceMachPort + 88
3 CoreFoundation 0x33a47ed2 __CFRunLoopRun + 350
4 CoreFoundation 0x33a47c80 CFRunLoopRunSpecific + 224
5 CoreFoundation 0x33a47b88 CFRunLoopRunInMode + 52
6 Foundation 0x336465f6 +[NSURLConnection(NSURLConnectionReallyInternal) _resourceLoadLoop:] + 206
7 Foundation 0x33624192 -[NSThread main] + 38
8 Foundation 0x3361d242 __NSThread__main__ + 966
9 libSystem.B.dylib 0x33bd6886 _pthread_start + 242
10 libSystem.B.dylib 0x33bcba88 thread_start + 0
Thread 4:
0 libSystem.B.dylib 0x33b8168c select$DARWIN_EXTSN + 20
1 CoreFoundation 0x33a7f662 __CFSocketManager + 582
2 libSystem.B.dylib 0x33bd6886 _pthread_start + 242
3 libSystem.B.dylib 0x33bcba88 thread_start + 0
Thread 5:
0 libSystem.B.dylib 0x33bd79e0 __workq_kernreturn + 8
1 libSystem.B.dylib 0x33bd7364 _pthread_wqthread + 540
2 libSystem.B.dylib 0x33bcf970 start_wqthread + 0
Thread 6:
0 libSystem.B.dylib 0x33bd79e0 __workq_kernreturn + 8
1 libSystem.B.dylib 0x33bd7364 _pthread_wqthread + 540
2 libSystem.B.dylib 0x33bcf970 start_wqthread + 0
Unknown thread crashed with unknown flavor: 5, state_count: 1
更新:似乎与此问题相关的更紧密的线程已打开.该错误与重定向HTTP连接(异步和同步NRURL操作)有关.也许，因为NSURLConnection是从基础框架继承的，那么该错误也存在于iPhone上吗?
UPDATE: Seems that a closer thread related to this issue is open here.The bug is related to redirect http connections, both async and sync NRURL operations. Perhaps, since NSURLConnection inherits from the foundation framework, then the bug is present on iPhone too?
openradar，网址为: 1062401
openradar at: 1062401
推荐答案
我的调查显示，无论是什么原因，您都会在下面看到异常:
My investigation shows that, whatever reason really is, you get the exception below:
TMS[13544] has active assertions beyond permitted time:
{(
<SBProcessAssertion: 0x8cb6040> identifier: UIKitBackgroundCompletionTask process: TMS[13544] permittedBackgroundDuration: 600.000000 reason: finishTask owner pid:13544 preventSuspend preventIdleSleep
)}
如果代码不执行`endBackgroundTask:'方法.
if the code doesn't execute`endBackgroundTask:' method.
这意味着使用beginBackgroundTaskWithExpirationHandler:' call MUST be ended with endBackgroundTask:'创建的每个后台任务.仔细检查是否使用正确的任务ID调用了"endBackgroundTask:".
This means that EVERY background task created with beginBackgroundTaskWithExpirationHandler:' call MUST be ended withendBackgroundTask:'.Double check that `endBackgroundTask:' is invoked with the correct task id.
这篇关于UIKitBackgroundCompletionTask-iPhone应用程序崩溃的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！