我的应用程序崩溃了一些用户的问题，我不知道是什么导致它，我得到的只是来自crashlytics的这个堆栈跟踪：
Thread : Crashed: com.apple.main-thread
0 libobjc.A.dylib 0x0000000194e5016c objc_release + 12
1 learnchinese 0x00000001000a95a0 -[WGRLanguageLabel .cxx_destruct] (WGRLanguageLabel.m:34)
2 libobjc.A.dylib 0x0000000194e36b1c object_cxxDestructFromClass(objc_object*, objc_class*) + 148
3 libobjc.A.dylib 0x0000000194e43f38 objc_destructInstance + 92
4 libobjc.A.dylib 0x0000000194e43f90 object_dispose + 28
5 UIKit 0x0000000187f8771c -[UIResponder dealloc] + 116
6 UIKit 0x0000000187c3dc38 -[UIView dealloc] + 1000
7 learnchinese 0x00000001000a5460 -[WGRLanguageLabel dealloc] (WGRLanguageLabel.m:39)
8 CoreFoundation 0x00000001830a10f8 CFRelease + 524
9 CoreFoundation 0x00000001830ad6b8 -[__NSArrayM dealloc] + 152
10 libobjc.A.dylib 0x0000000194e51724 (anonymous namespace)::AutoreleasePoolPage::pop(void*) + 564
11 CoreFoundation 0x00000001830a4d14 _CFAutoreleasePoolPop + 28
12 UIKit 0x0000000187c34584 _wrapRunLoopWithAutoreleasePoolHandler + 76
13 CoreFoundation 0x000000018317bff0 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 32
14 CoreFoundation 0x0000000183178f7c __CFRunLoopDoObservers + 360
15 CoreFoundation 0x000000018317935c __CFRunLoopRun + 836
16 CoreFoundation 0x00000001830a4f74 CFRunLoopRunSpecific + 396
17 GraphicsServices 0x000000018cb076fc GSEventRunModal + 168
18 UIKit 0x0000000187ca6d94 UIApplicationMain + 1488
19 learnchinese 0x00000001001679ec main (main.m:13)
20 libdyld.dylib 0x00000001954e2a08 start + 4
当自动发布池尝试再次发布时，WGRLanguageLabel似乎已经发布。
这是WGRLanguageLabel中的dealloc方法：
@implementation WGRLanguageLabel
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
...
@end