找不到错误造成的“超出允许的时间积极主张”撞车

Question

我正在以下崩溃日志，显示我的应用程序具有“超越许可的时间活跃断言”。我的应用是一个音频流应用。只有当应用程序处于后台并且不流式播放任何音频内容时才会发生崩溃。

注：

• 我保证beginBackgroundTaskWithExpirationHandler在applicationDidEnterBackground具有在applicationWillEnterForeground相应endBackgroundTask。
• 所有网络访问都在自己的线程，而不是在主线程。
• 当应用程序在后台没有尝试任何线程访问网络。
• 误差是随机的，并且不能由切换装置飞行模式或关闭无线网络被复制。

如何追踪下来有什么建议？

这里是崩溃日志（不二进制图像）：

Incident Identifier: 0467A340-1FD2-4D49-9FA4-76360889976D 
CrashReporter Key: fdae46f133d13bdc3f043301bc008bd56155588d 
Hardware Model:  iPhone3,1 
Process:   MyApp [249] 
Path:   /var/mobile/Applications/DAA6B446-07D3-4C7C-BD44-80920338CAF4/MyApp/MyApp 
Identifier:  MyApp 
Version:   ??? (???) 
Code Type:  ARM (Native) 
Parent Process: launchd [1] 

Date/Time:  2011-11-17 15:25:59.960 -0500 
OS Version:  iPhone OS 5.0.1 (9A405) 
Report Version: 104 

Exception Type: 00000020 
Exception Codes: 0x8badf00d 
Highlighted Thread: 4 

Application Specific Information: 
MyApp[249] has active assertions beyond permitted time: 
{(
    <SBProcessAssertion: 0xfed8890> identifier: UIKitBackgroundCompletionTask process: MyApp[249] permittedBackgroundDuration: 600.000000 reason: finishTask owner pid:249 preventSuspend preventIdleSleep 
)} 

Elapsed total CPU time (seconds): 10.700 (user 10.700, system 0.000), 2% CPU 
Elapsed application CPU time (seconds): 0.024, 0% CPU 

Thread 0 name: Dispatch queue: com.apple.main-thread 
Thread 0: 
0 libsystem_kernel.dylib   0x3630f010 0x3630e000 + 4112 
1 libsystem_kernel.dylib   0x3630f206 0x3630e000 + 4614 
2 CoreFoundation     0x343d841c 0x3434b000 + 578588 
3 CoreFoundation     0x343d711a 0x3434b000 + 573722 
4 CoreFoundation     0x3435a4d6 0x3434b000 + 62678 
5 CoreFoundation     0x3435a39e 0x3434b000 + 62366 
6 GraphicsServices    0x30bdefc6 0x30bdb000 + 16326 
7 UIKit       0x377db73c 0x377aa000 + 202556 
8 MyApp      0x000024de main (main.m:14) 
9 MyApp      0x0000249c start + 32 

Thread 1 name: Dispatch queue: com.apple.libdispatch-manager 
Thread 1: 
0 libsystem_kernel.dylib   0x3630f3b4 0x3630e000 + 5044 
1 libdispatch.dylib    0x37039e78 0x3702d000 + 52856 
2 libdispatch.dylib    0x37039b96 0x3702d000 + 52118 

Thread 2 name: WebThread 
Thread 2: 
0 libsystem_kernel.dylib   0x3630f010 0x3630e000 + 4112 
1 libsystem_kernel.dylib   0x3630f206 0x3630e000 + 4614 
2 CoreFoundation     0x343d841c 0x3434b000 + 578588 
3 CoreFoundation     0x343d7154 0x3434b000 + 573780 
4 CoreFoundation     0x3435a4d6 0x3434b000 + 62678 
5 CoreFoundation     0x3435a39e 0x3434b000 + 62366 
6 WebCore       0x3682e128 0x36786000 + 688424 
7 libsystem_c.dylib    0x331aac16 0x3319b000 + 64534 
8 libsystem_c.dylib    0x331aaad0 0x3319b000 + 64208 

Thread 3 name: com.apple.coremedia.player.async 
Thread 3: 
0 libsystem_kernel.dylib   0x3631f068 0x3630e000 + 69736 
1 libsystem_c.dylib    0x331aaf2e 0x3319b000 + 65326 
2 libsystem_c.dylib    0x331aacaa 0x3319b000 + 64682 
3 CoreMedia      0x32306000 0x32303000 + 12288 
4 MediaToolbox     0x35169fba 0x35166000 + 16314 
5 CoreMedia      0x32325bc6 0x32303000 + 142278 
6 libsystem_c.dylib    0x331aac16 0x3319b000 + 64534 
7 libsystem_c.dylib    0x331aaad0 0x3319b000 + 64208 

Thread 4 name: com.apple.NSURLConnectionLoader 
Thread 4: 
0 libsystem_kernel.dylib   0x3630f010 0x3630e000 + 4112 
1 libsystem_kernel.dylib   0x3630f206 0x3630e000 + 4614 
2 CoreFoundation     0x343d841c 0x3434b000 + 578588 
3 CoreFoundation     0x343d7154 0x3434b000 + 573780 
4 CoreFoundation     0x3435a4d6 0x3434b000 + 62678 
5 CoreFoundation     0x3435a39e 0x3434b000 + 62366 
6 Foundation      0x35d5abc2 0x35d4a000 + 68546 
7 Foundation      0x35d5aa8a 0x35d4a000 + 68234 
8 Foundation      0x35dee59a 0x35d4a000 + 673178 
9 libsystem_c.dylib    0x331aac16 0x3319b000 + 64534 
10 libsystem_c.dylib    0x331aaad0 0x3319b000 + 64208 

Thread 5 name: com.apple.CFSocket.private 
Thread 5: 
0 libsystem_kernel.dylib   0x3631f570 0x3630e000 + 71024 
1 CoreFoundation     0x343dc66a 0x3434b000 + 595562 
2 libsystem_c.dylib    0x331aac16 0x3319b000 + 64534 
3 libsystem_c.dylib    0x331aaad0 0x3319b000 + 64208 

Unknown thread crashed with unknown flavor: 5, state_count: 1 

Answer 1

beginBackgroundTaskWithExpirationHandler有可能会超过时间限制。您可以看到UIApplication的backgroundTimeRemaining属性重新处理了多少时间。

Answer 2

你不能依靠你的结束后台任务时，通过applicationWillEnterForeground应用程序返回到前台（）。 iOS只允许3分钟在后台执行工作。这就是后台任务开始方法有一个到期处理程序的原因。你应该清理你的任务（非常快），并结束该任务（通过endBackgroundTask）时到期处理程序被调用：

UIBackgroundTaskIdentifier bkgndTask; 
--- 
bkgndTask = [app beginBackgroundTaskWithExpirationHandler:^{ 
    if (bkgndTask != UIBackgroundTaskInvalid) { 
     [[UIApplication sharedApplication] bkgndTask]; 
     bkgndTask = UIBackgroundTaskInvalid; 
    } 
}];